diff options
Diffstat (limited to 'doc/sphinx')
40 files changed, 8388 insertions, 3615 deletions
diff --git a/doc/sphinx/MIGRATING b/doc/sphinx/MIGRATING deleted file mode 100644 index fa6fe15379..0000000000 --- a/doc/sphinx/MIGRATING +++ /dev/null @@ -1,238 +0,0 @@ -How to migrate the Coq Reference Manual to Sphinx -================================================= - -# Install Python3 packages (requires Python 3, python3-pip, python3-setuptools) - - * pip3 install bs4 sphinx sphinx_rtd_theme pexpect antlr4-python3-runtime sphinxcontrib-bibtex - -# You may want to do this under a virtualenv, particularly if you end up with issues finding sphinxcontrib.bibtex. http://docs.python-guide.org/en/latest/dev/virtualenvs/ - - * pip3 install virtualenv - * virtualenv coqsphinxing # you may want to use -p to specify the python version - * source coqsphinxing/bin/activate # activate the virtual environment - -# After activating the virtual environment you can run the above pip3 command to install sphinx. You will have to activate the virtual environment before building the docs in your session. - -# Add this Elisp code to .emacs, if you're using emacs (recommended): - - (defun sphinx/quote-coq-refman-region (left right &optional beg end count) - (unless beg - (if (region-active-p) - (setq beg (region-beginning) end (region-end)) - (setq beg (point) end nil))) - (unless count - (setq count 1)) - (save-excursion - (goto-char (or end beg)) - (dotimes (_ count) (insert right))) - (save-excursion - (goto-char beg) - (dotimes (_ count) (insert left))) - (if (and end (characterp left)) ;; Second test handles the ::`` case - (goto-char (+ (* 2 count) end)) - (goto-char (+ count beg)))) - - (defun sphinx/coqtop (beg end) - (interactive (list (region-beginning) (region-end))) - (replace-regexp "^Coq < " " " nil beg end) - (indent-rigidly beg end -3) - (goto-char beg) - (insert ".. coqtop:: all\n\n")) - - (defun sphinx/rst-coq-action () - (interactive) - (pcase (read-char "Command?") - (?g (sphinx/quote-coq-refman-region ":g:`" "`")) - (?n (sphinx/quote-coq-refman-region ":n:`" "`")) - (?t (sphinx/quote-coq-refman-region ":token:`" "`")) - (?m (sphinx/quote-coq-refman-region ":math:`" "`")) - (?: (sphinx/quote-coq-refman-region "::`" "`")) - (?` (sphinx/quote-coq-refman-region "``" "``")) - (?c (sphinx/coqtop (region-beginning) (region-end))))) - - (global-set-key (kbd "<f12>") #'sphinx/rst-coq-action) - - With this code installed, you can hit "F12" followed by an appropriate key to do quick markup of text - (this will make more sense once you've started editing the text). - -# Fork the Coq repo, if needed: - - https://github.com/coq/coq - -# Clone the repo to your work machine - -# Add Maxime Dénès's repo as a remote: - - git remote add sphinx https://github.com/maximedenes/coq.git - - (or choose a name other than "sphinx") - - Verify with: - - git remote -v - -# Fetch from the remote - - git fetch sphinx - -# Checkout the sphinx-doc branch - - git checkout sphinx-doc - - You should pull from the repo from time to time to keep your local copy up-to-date: - - git pull sphinx sphinx-doc - - You may want to create a new branch to do your work in. - -# Choose a Reference Manual chapter to work on at - - https://docs.google.com/document/d/1Yo7dV4OI0AY9Di-lsEQ3UTmn5ygGLlhxjym7cTCMCWU - -# For each chapter, raw ReStructuredText (the Sphinx format), created by the "html2rest" utility, - is available in the directory porting/raw-rst/ - - Elsewhere, depending on the chapter, there should be an almost-empty template file already created, - which is in the location where the final version should go - -# Manually edit the .rst file, place it in the correct location - - There are small examples in sphinx/porting/, a larger example in language/gallina-extensions.rst - - (N.B.: the migration is a work-in-progress, your suggestions are welcome) - - Find the chapter you're working on from the online manual at https://coq.inria.fr/distrib/current/refman/. - At the top of the file, after the chapter heading, add: - - :Source: https://coq.inria.fr/distrib/current/refman/the-chapter-file.html - :Converted by: Your Name - - N.B.: These source and converted-by annotations should help for the migration phase. Later on, - those annotations will be removed, and contributors will be mentioned in the Coq credits. - - Remove chapter numbers - - Replace section, subsection numbers with reference labels: - - .. _some-reference-label: - - Place the label before the section or subsection, followed by a blank line. - - Note the leading underscore. Use :ref:`some_reference-label` to refer to such a label; note the leading underscore is omitted. - Many cross-references may be to other chapters. If the required label exists, use it. Otherwise, use a dummy reference of the form - `TODO-n.n.n-mnemonic` we can fixup later. Example: - - :ref:`TODO-1.3.2-definitions` - - We can grep for those TODOs, and the existing subsection number makes it easy to find in the exisyting manual. - - For the particular case of references to chapters, we can use a -convention for the cross-reference name, so no TODO is needed. - - :ref:`thegallinaspecificationlanguage` - -That is, the chapter label is the chapter title, all in lower-case, -with no spaces or punctuation. For chapters with subtitles marked with -a ":", like those for Omega and Nsatz, use just the chapter part -preceding the ":". These labels should already be in the -placeholder .rst files for each chapter. - - - You can also label other items, like grammars, with the same syntax. To refer to such labels, not involving a - section or subsection, use the syntax - - :ref:`Some link text <label-name>` - - Yes, the angle-brackets are needed here! - - For bibliographic references (those in biblio.bib), use :cite:`thecitation`. - - Grammars will get mangled by the translation. Look for "productionlist" in the examples, also see - http://www.sphinx-doc.org/en/stable/markup/para.html. - - For Coq examples that appear, look at the "coqtop" syntax in porting/tricky-bits.rst. The Sphinx - script will run coqtop on those examples, and can show the output (or not). - - The file replaces.rst contains replacement definitions for some items that are clumsy to write out otherwise. - Use - - .. include:: replaces.rst - - to gain access to those definitions in your file (you might need a path prefix). Some especially-important - replacements are |Cic|, |Coq|, |CoqIDE|, and |Gallina|, which display those names in small-caps. Please use them, - so that they're rendered consistently. - - Similarly, there are some LaTeX macros in preamble.rst that can be useful. - - Conventions: - - - Keywords and other literal text is double-backquoted (e.g. ``Module``, ``Section``, ``(``, ``,``). - - - Metavariables are single-backquotes (e.g. `term`, `ident`) - - - Use the cmd directive for Vernacular commands, like: - - .. cmd:: Set Printing All. - - Within this directive, prefix metavariables (ident, term) with @: - - .. cmd:: Add Printing Let @ident. - - There's also the "cmdv" directive for variants of a command. - - - Use the "exn" and "warn" directives for errors and warnings: - - .. exn:: Something's not right. - .. warn:: You shouldn't do that. - - - Use the "example" directive for examples - - - Use the "g" role for inline Gallina, like :g:`fun x => x` - - - Use code blocks for blocks of Gallina. You can use a double-colon at the end of a line:: - - your code here - - which prints a single colon, or put the double-colon on a newline. - -:: - - your other code here - -# Making changes to the text - - The goal of the migration is simply to change the storage format from LaTeX to ReStructuredText. The goal is not - to make any organizational or other substantive changes to the text. If you do notice nits (misspellings, wrong - verb tense, and so on), please do change them. For example, the programming language that Coq is written in is these days - called "OCaml", and there are mentions of the older name "Objective Caml" in the reference manual that should be changed. - -# Build, view the manual - - In the root directory of your local repo, run "make sphinx". You can view the result in a browser by loading the HTML file - associated with your chapter, which will be contained in the directory doc/sphinx/_build/html/ beneath the repo root directory. - Make any changes you need until there are no build warnings and the output is perfect. :-) - -# Creating pull requests - - When your changes are done, commit them, push to your fork: - - git commit -m "useful commit message" file - git push origin sphinx-doc - - (or push to another branch, if you've created one). Then go to your GitHub - fork and create a pull request against Maxime's sphinx-doc - branch. If your commit is recent, you should see a link on your - fork's code page to do that. Otherwise, you may need to go to your - branch on GitHub to do that. - -# Issues/Questions/Suggestions - - As the migration proceeds, if you have technical issues, have a more general question, or want to suggest something, please contact: - - Paul Steckler <steck@stecksoft.com> - Maxime Dénès <maxime.denes@inria.fr> - -# Issues - - Should the stuff in replaces.rst go in preamble.rst? - In LaTeX, some of the grammars add productions to existing nonterminals, like term ++= ... . How to indicate that? diff --git a/doc/sphinx/README.rst b/doc/sphinx/README.rst new file mode 100644 index 0000000000..35a605ddd3 --- /dev/null +++ b/doc/sphinx/README.rst @@ -0,0 +1,395 @@ +============================= + Documenting Coq with Sphinx +============================= + +.. + README.rst is auto-generated from README.template.rst and the coqrst docs; + use ``doc/tools/coqrst/regen_readme.py`` to rebuild it. + +Coq's reference manual is written in `reStructuredText <http://www.sphinx-doc.org/en/master/usage/restructuredtext/basics.html>`_ (“reST”), and compiled with `Sphinx <http://www.sphinx-doc.org/en/master/>`_. + +In addition to standard reST directives (a directive is similar to a LaTeX environment) and roles (a role is similar to a LaTeX command), the ``coqrst`` plugin loaded by the documentation uses a custom *Coq domain* — a set of Coq-specific directives that define *objects* like tactics, commands (vernacs), warnings, etc. —, some custom *directives*, and a few custom *roles*. Finally, this manual uses a small DSL to describe tactic invocations and commands. + +Coq objects +=========== + +Our Coq domain define multiple `objects`_. Each object has a *signature* (think *type signature*), followed by an optional body (a description of that object). The following example defines two objects: a variant of the ``simpl`` tactic, and an error that it may raise:: + + .. tacv:: simpl @pattern at {+ @num} + :name: simpl_at + + This applies ``simpl`` only to the :n:`{+ @num}` occurrences of the subterms + matching :n:`@pattern` in the current goal. + + .. exn:: Too few occurrences + :undocumented: + +Objects are automatically collected into indices, and can be linked to using the role version of the object's directive. For example, you could link to the tactic variant above using ``:tacv:`simpl_at```, and to its exception using ``:exn:`Too few occurrences```. + +Names (link targets) are auto-generated for most simple objects, though they can always be overwritten using a ``:name:`` option, as shown above. + +- Options, errors, warnings have their name set to their signature, with ``...`` replacing all notation bits. For example, the auto-generated name of ``.. exn:: @qualid is not a module`` is ``... is not a module``, and a link to it would take the form ``:exn:`... is not a module```. +- Vernacs (commands) have their name set to the first word of their signature. For example, the auto-generated name of ``Axiom @ident : @term`` is ``Axiom``, and a link to it would take the form ``:cmd:`Axiom```. +- Vernac variants, tactic notations, and tactic variants do not have a default name. + +Most objects should have a body (i.e. a block of indented text following the signature, called “contents” in Sphinx terms). Undocumented objects should have the `:undocumented:` flag instead, as shown above. When multiple objects have a single description, they can be grouped into a single object, like this (semicolons can be used to separate the names of the objects):: + + .. cmdv:: Lemma @ident {? @binders} : @type + Remark @ident {? @binders} : @type + Fact @ident {? @binders} : @type + Corollary @ident {? @binders} : @type + Proposition @ident {? @binders} : @type + :name: Lemma; Remark; Fact; Corollary; Proposition + + These commands are all synonyms of :n:`Theorem @ident {? @binders } : type`. + +Notations +--------- + +The signatures of most objects can be written using a succinct DSL for Coq notations (think regular expressions written with a Lispy syntax). A typical signature might look like ``Hint Extern @num {? @pattern} => @tactic``, which means that the ``Hint Extern`` command takes a number (``num``), followed by an optional pattern, and a mandatory tactic. The language has the following constructs (the full grammar is in `TacticNotations.g </doc/tools/coqrst/notations/TacticNotations.g>`_): + +``@…`` + A placeholder (``@ident``, ``@num``, ``@tactic``\ …) + +``{? …}`` + an optional block + +``{* …}``, ``{+ …}`` + an optional (``*``) or mandatory (``+``) block that can be repeated, with repetitions separated by spaces + +``{*, …}``, ``{+, …}`` + an optional or mandatory repeatable block, with repetitions separated by commas + +``%|``, ``%{``, … + an escaped character (rendered without the leading ``%``) + +.. + FIXME document the new subscript support + +As an exercise, what do the following patterns mean? + +.. code:: + + pattern {+, @term {? at {+ @num}}} + generalize {+, @term at {+ @num} as @ident} + fix @ident @num with {+ (@ident {+ @binder} {? {struct @ident'}} : @type)} + +Objects +------- + +Here is the list of all objects of the Coq domain (The symbol :black_nib: indicates an object whose signature can be written using the notations DSL): + +``.. cmd::`` :black_nib: A Coq command. + Example:: + + .. cmd:: Infix "@symbol" := @term ({+, @modifier}). + + This command is equivalent to :n:`…`. + +``.. cmdv::`` :black_nib: A variant of a Coq command. + Example:: + + .. cmd:: Axiom @ident : @term. + + This command links :token:`term` to the name :token:`term` as its specification in + the global context. The fact asserted by :token:`term` is thus assumed as a + postulate. + + .. cmdv:: Parameter @ident : @term. + + This is equivalent to :n:`Axiom @ident : @term`. + +``.. exn::`` :black_nib: An error raised by a Coq command or tactic. + This commonly appears nested in the ``.. tacn::`` that raises the + exception. + + Example:: + + .. tacv:: assert @form by @tactic + + This tactic applies :n:`@tactic` to solve the subgoals generated by + ``assert``. + + .. exn:: Proof is not complete + + Raised if :n:`@tactic` does not fully solve the goal. + +``.. opt::`` :black_nib: A Coq option. + Example:: + + .. opt:: Nonrecursive Elimination Schemes + + This option controls whether types declared with the keywords + :cmd:`Variant` and :cmd:`Record` get an automatic declaration of the + induction principles. + +``.. prodn::`` :black_nib: Grammar productions. + This is useful if you intend to document individual grammar productions. + Otherwise, use Sphinx's `production lists + <http://www.sphinx-doc.org/en/stable/markup/para.html#directive-productionlist>`_. + +``.. tacn::`` :black_nib: A tactic, or a tactic notation. + Example:: + + .. tacn:: do @num @expr + + :token:`expr` is evaluated to ``v`` which must be a tactic value. … + +``.. tacv::`` :black_nib: A variant of a tactic. + Example:: + + .. tacn:: fail + + This is the always-failing tactic: it does not solve any goal. It is + useful for defining other tacticals since it can be caught by + :tacn:`try`, :tacn:`repeat`, :tacn:`match goal`, or the branching + tacticals. … + + .. tacv:: fail @natural + + The number is the failure level. If no level is specified, it + defaults to 0. … + +``.. thm::`` A theorem. + Example:: + + .. thm:: Bound on the ceiling function + + Let :math:`p` be an integer and :math:`c` a rational constant. Then + :math:`p \ge c \rightarrow p \ge \lceil{c}\rceil`. + +``.. warn::`` :black_nib: An warning raised by a Coq command or tactic.. + Do not mistake this for ``.. warning::``; this directive is for warning + messages produced by Coq. + + + Example:: + + .. warn:: Ambiguous path + + When the coercion :token:`qualid` is added to the inheritance graph, non + valid coercion paths are ignored. + +Coq directives +============== + +In addition to the objects above, the ``coqrst`` Sphinx plugin defines the following directives: + +``.. coqtop::`` A reST directive to describe interactions with Coqtop. + Usage:: + + .. coqtop:: options… + + Coq code to send to coqtop + + Example:: + + .. coqtop:: in reset undo + + Print nat. + Definition a := 1. + + Here is a list of permissible options: + + - Display options + + - ``all``: Display input and output + - ``in``: Display only input + - ``out``: Display only output + - ``none``: Display neither (useful for setup commands) + + - Behavior options + + - ``reset``: Send a ``Reset Initial`` command before running this block + - ``undo``: Send an ``Undo n`` (``n`` = number of sentences) command after + running all the commands in this block + + ``coqtop``\ 's state is preserved across consecutive ``.. coqtop::`` blocks + of the same document (``coqrst`` creates a single ``coqtop`` process per + reST source file). Use the ``reset`` option to reset Coq's state. + +``.. coqdoc::`` A reST directive to display Coqtop-formatted source code. + Usage:: + + .. coqdoc:: + + Coq code to highlight + + Example:: + + .. coqdoc:: + + Definition test := 1. + +``.. example::`` A reST directive for examples. + This behaves like a generic admonition; see + http://docutils.sourceforge.net/docs/ref/rst/directives.html#generic-admonition + for more details. + + Example:: + + .. example:: Adding a hint to a database + + The following adds ``plus_comm`` to the ``plu`` database: + + .. coqdoc:: + + Hint Resolve plus_comm : plu. + +``.. inference::`` A reST directive to format inference rules. + This also serves as a small illustration of the way to create new Sphinx + directives. + + Usage:: + + .. inference:: name + + newline-separated premisses + ------------------------ + conclusion + + Example:: + + .. inference:: Prod-Pro + + \WTEG{T}{s} + s \in \Sort + \WTE{\Gamma::(x:T)}{U}{\Prop} + ----------------------------- + \WTEG{\forall~x:T,U}{\Prop} + +``.. preamble::`` A reST directive for hidden math. + Mostly useful to let MathJax know about `\def`\ s and `\newcommand`\ s. + + Example:: + + .. preamble:: + + \newcommand{\paren}[#1]{\left(#1\right)} + +Coq roles +========= + +In addition to the objects and directives above, the ``coqrst`` Sphinx plugin defines the following roles: + +``:g:`` Coq code. + Use this for Gallina and Ltac snippets:: + + :g:`apply plus_comm; reflexivity` + :g:`Set Printing All.` + :g:`forall (x: t), P(x)` + +``:n:`` Any text using the notation syntax (``@id``, ``{+, …}``, etc.). + Use this to explain tactic equivalences. For example, you might write + this:: + + :n:`generalize @term as @ident` is just like :n:`generalize @term`, but + it names the introduced hypothesis :token:`ident`. + + Note that this example also uses ``:token:``. That's because ``ident`` is + defined in the the Coq manual as a grammar production, and ``:token:`` + creates a link to that. When referring to a placeholder that happens to be + a grammar production, ``:token:`…``` is typically preferable to ``:n:`@…```. + +``:production:`` A grammar production not included in a ``productionlist`` directive. + Useful to informally introduce a production, as part of running text. + + Example:: + + :production:`string` indicates a quoted string. + + You're not likely to use this role very commonly; instead, use a + `production list + <http://www.sphinx-doc.org/en/stable/markup/para.html#directive-productionlist>`_ + and reference its tokens using ``:token:`…```. + +Common mistakes +=============== + +Improper nesting +---------------- + +DO + .. code:: + + .. cmd:: Foo @bar + + Foo the first instance of :token:`bar`\ s. + + .. cmdv:: Foo All + + Foo all the :token:`bar`\ s in + the current context + +DON'T + .. code:: + + .. cmd:: Foo @bar + + Foo the first instance of :token:`bar`\ s. + + .. cmdv:: Foo All + + Foo all the :token:`bar`\ s in + the current context + +You can set the ``report_undocumented_coq_objects`` setting in ``conf.py`` to ``"info"`` or ``"warning"`` to get a list of all Coq objects without a description. + +Overusing ``:token:`` +--------------------- + +DO + .. code:: + + This is equivalent to :n:`Axiom @ident : @term`. + +DON'T + .. code:: + + This is equivalent to ``Axiom`` :token`ident` : :token:`term`. + +Omitting annotations +-------------------- + +DO + .. code:: + + .. tacv:: assert @form as @intro_pattern + +DON'T + .. code:: + + .. tacv:: assert form as intro_pattern + +Tips and tricks +=============== + +Nested lemmas +------------- + +The ``.. coqtop::`` directive does *not* reset Coq after running its contents. That is, the following will create two nested lemmas:: + + .. coqtop:: all + + Lemma l1: 1 + 1 = 2. + + .. coqtop:: all + + Lemma l2: 2 + 2 <> 1. + +Add either ``undo`` to the first block or ``reset`` to the second block to avoid nesting lemmas. + +Abbreviations and macros +------------------------ + +Abbreviations and placeholders for specially-formatted names (like ``|Cic|``, ``|Coq|``, ``|CoqIDE|``, ``|Ltac|``, and ``|Gallina|``) are defined in a `separate file </doc/sphinx/replaces.rst>`_ included by most chapters of the manual. Some useful LaTeX macros are defined in `</doc/sphinx/preamble.rst>`_. + +Emacs +----- + +The ``dev/tools/coqdev.el`` folder contains a convenient Emacs function to quickly insert Sphinx roles and quotes. It takes a single character (one of ``gntm:```), and inserts one of ``:g:``, ``:n:``, ``:t:``, or an arbitrary role, or double quotes. You can also select a region of text, and wrap it in single or double backticks using that function. + +Use the following snippet to bind it to :kbd:`F12` in ``rst-mode``:: + + (with-eval-after-load 'rst + (define-key rst-mode-map (kbd "<f12>") #'coqdev-sphinx-rst-coq-action)) diff --git a/doc/sphinx/README.template.rst b/doc/sphinx/README.template.rst new file mode 100644 index 0000000000..f1d2541eb6 --- /dev/null +++ b/doc/sphinx/README.template.rst @@ -0,0 +1,187 @@ +============================= + Documenting Coq with Sphinx +============================= + +.. + README.rst is auto-generated from README.template.rst and the coqrst docs; + use ``doc/tools/coqrst/regen_readme.py`` to rebuild it. + +Coq's reference manual is written in `reStructuredText <http://www.sphinx-doc.org/en/master/usage/restructuredtext/basics.html>`_ (“reST”), and compiled with `Sphinx <http://www.sphinx-doc.org/en/master/>`_. + +In addition to standard reST directives (a directive is similar to a LaTeX environment) and roles (a role is similar to a LaTeX command), the ``coqrst`` plugin loaded by the documentation uses a custom *Coq domain* — a set of Coq-specific directives that define *objects* like tactics, commands (vernacs), warnings, etc. —, some custom *directives*, and a few custom *roles*. Finally, this manual uses a small DSL to describe tactic invocations and commands. + +Coq objects +=========== + +Our Coq domain define multiple `objects`_. Each object has a *signature* (think *type signature*), followed by an optional body (a description of that object). The following example defines two objects: a variant of the ``simpl`` tactic, and an error that it may raise:: + + .. tacv:: simpl @pattern at {+ @num} + :name: simpl_at + + This applies ``simpl`` only to the :n:`{+ @num}` occurrences of the subterms + matching :n:`@pattern` in the current goal. + + .. exn:: Too few occurrences + :undocumented: + +Objects are automatically collected into indices, and can be linked to using the role version of the object's directive. For example, you could link to the tactic variant above using ``:tacv:`simpl_at```, and to its exception using ``:exn:`Too few occurrences```. + +Names (link targets) are auto-generated for most simple objects, though they can always be overwritten using a ``:name:`` option, as shown above. + +- Options, errors, warnings have their name set to their signature, with ``...`` replacing all notation bits. For example, the auto-generated name of ``.. exn:: @qualid is not a module`` is ``... is not a module``, and a link to it would take the form ``:exn:`... is not a module```. +- Vernacs (commands) have their name set to the first word of their signature. For example, the auto-generated name of ``Axiom @ident : @term`` is ``Axiom``, and a link to it would take the form ``:cmd:`Axiom```. +- Vernac variants, tactic notations, and tactic variants do not have a default name. + +Most objects should have a body (i.e. a block of indented text following the signature, called “contents” in Sphinx terms). Undocumented objects should have the `:undocumented:` flag instead, as shown above. When multiple objects have a single description, they can be grouped into a single object, like this (semicolons can be used to separate the names of the objects):: + + .. cmdv:: Lemma @ident {? @binders} : @type + Remark @ident {? @binders} : @type + Fact @ident {? @binders} : @type + Corollary @ident {? @binders} : @type + Proposition @ident {? @binders} : @type + :name: Lemma; Remark; Fact; Corollary; Proposition + + These commands are all synonyms of :n:`Theorem @ident {? @binders } : type`. + +Notations +--------- + +The signatures of most objects can be written using a succinct DSL for Coq notations (think regular expressions written with a Lispy syntax). A typical signature might look like ``Hint Extern @num {? @pattern} => @tactic``, which means that the ``Hint Extern`` command takes a number (``num``), followed by an optional pattern, and a mandatory tactic. The language has the following constructs (the full grammar is in `TacticNotations.g </doc/tools/coqrst/notations/TacticNotations.g>`_): + +``@…`` + A placeholder (``@ident``, ``@num``, ``@tactic``\ …) + +``{? …}`` + an optional block + +``{* …}``, ``{+ …}`` + an optional (``*``) or mandatory (``+``) block that can be repeated, with repetitions separated by spaces + +``{*, …}``, ``{+, …}`` + an optional or mandatory repeatable block, with repetitions separated by commas + +``%|``, ``%{``, … + an escaped character (rendered without the leading ``%``) + +.. + FIXME document the new subscript support + +As an exercise, what do the following patterns mean? + +.. code:: + + pattern {+, @term {? at {+ @num}}} + generalize {+, @term at {+ @num} as @ident} + fix @ident @num with {+ (@ident {+ @binder} {? {struct @ident'}} : @type)} + +Objects +------- + +Here is the list of all objects of the Coq domain (The symbol :black_nib: indicates an object whose signature can be written using the notations DSL): + +[OBJECTS] + +Coq directives +============== + +In addition to the objects above, the ``coqrst`` Sphinx plugin defines the following directives: + +[DIRECTIVES] + +Coq roles +========= + +In addition to the objects and directives above, the ``coqrst`` Sphinx plugin defines the following roles: + +[ROLES] + +Common mistakes +=============== + +Improper nesting +---------------- + +DO + .. code:: + + .. cmd:: Foo @bar + + Foo the first instance of :token:`bar`\ s. + + .. cmdv:: Foo All + + Foo all the :token:`bar`\ s in + the current context + +DON'T + .. code:: + + .. cmd:: Foo @bar + + Foo the first instance of :token:`bar`\ s. + + .. cmdv:: Foo All + + Foo all the :token:`bar`\ s in + the current context + +You can set the ``report_undocumented_coq_objects`` setting in ``conf.py`` to ``"info"`` or ``"warning"`` to get a list of all Coq objects without a description. + +Overusing ``:token:`` +--------------------- + +DO + .. code:: + + This is equivalent to :n:`Axiom @ident : @term`. + +DON'T + .. code:: + + This is equivalent to ``Axiom`` :token`ident` : :token:`term`. + +Omitting annotations +-------------------- + +DO + .. code:: + + .. tacv:: assert @form as @intro_pattern + +DON'T + .. code:: + + .. tacv:: assert form as intro_pattern + +Tips and tricks +=============== + +Nested lemmas +------------- + +The ``.. coqtop::`` directive does *not* reset Coq after running its contents. That is, the following will create two nested lemmas:: + + .. coqtop:: all + + Lemma l1: 1 + 1 = 2. + + .. coqtop:: all + + Lemma l2: 2 + 2 <> 1. + +Add either ``undo`` to the first block or ``reset`` to the second block to avoid nesting lemmas. + +Abbreviations and macros +------------------------ + +Abbreviations and placeholders for specially-formatted names (like ``|Cic|``, ``|Coq|``, ``|CoqIDE|``, ``|Ltac|``, and ``|Gallina|``) are defined in a `separate file </doc/sphinx/replaces.rst>`_ included by most chapters of the manual. Some useful LaTeX macros are defined in `</doc/sphinx/preamble.rst>`_. + +Emacs +----- + +The ``dev/tools/coqdev.el`` folder contains a convenient Emacs function to quickly insert Sphinx roles and quotes. It takes a single character (one of ``gntm:```), and inserts one of ``:g:``, ``:n:``, ``:t:``, or an arbitrary role, or double quotes. You can also select a region of text, and wrap it in single or double backticks using that function. + +Use the following snippet to bind it to :kbd:`F12` in ``rst-mode``:: + + (with-eval-after-load 'rst + (define-key rst-mode-map (kbd "<f12>") #'coqdev-sphinx-rst-coq-action)) diff --git a/doc/sphinx/_static/CoqNotations.ttf b/doc/sphinx/_static/CoqNotations.ttf Binary files differnew file mode 100644 index 0000000000..da8f2850df --- /dev/null +++ b/doc/sphinx/_static/CoqNotations.ttf diff --git a/doc/sphinx/_static/UbuntuMono-Square.ttf b/doc/sphinx/_static/UbuntuMono-Square.ttf Binary files differdeleted file mode 100644 index 12b7c6d51a..0000000000 --- a/doc/sphinx/_static/UbuntuMono-Square.ttf +++ /dev/null diff --git a/doc/sphinx/_static/notations.css b/doc/sphinx/_static/notations.css index 9b7b826d58..f899945a35 100644 --- a/doc/sphinx/_static/notations.css +++ b/doc/sphinx/_static/notations.css @@ -22,10 +22,10 @@ } @font-face { /* This font has been edited to center all characters */ - font-family: 'UbuntuMono-Square'; + font-family: 'CoqNotations'; font-style: normal; font-weight: 800; - src: local('UbuntuMono-Square'), url(./UbuntuMono-Square.ttf) format('truetype'); + src: local('CoqNotations'), url(./CoqNotations.ttf) format('truetype'); } .notation .notation-sup, .notation .notation-sub { @@ -34,15 +34,15 @@ color: black; /* cursor: help; */ display: inline-block; - font-size: 0.5em; + font-size: 0.45em; font-weight: bolder; - font-family: UbuntuMono-Square, monospace; - height: 2em; + font-family: CoqNotations, monospace; + height: 2.2em; line-height: 1.6em; position: absolute; right: -1em; /* half of the width */ text-align: center; - width: 2em; + width: 2.2em; } .notation .repeat { diff --git a/doc/sphinx/addendum/extended-pattern-matching.rst b/doc/sphinx/addendum/extended-pattern-matching.rst index 64d4eddf04..c4f0147728 100644 --- a/doc/sphinx/addendum/extended-pattern-matching.rst +++ b/doc/sphinx/addendum/extended-pattern-matching.rst @@ -46,7 +46,7 @@ the expressiveness of the theory remains the same. Once the stage of parsing has finished only simple patterns remain. Re-nesting of pattern is performed at printing time. An easy way to see the result of the expansion is to toggle off the nesting performed at printing -(use here :opt:`Set Printing Matching`), then by printing the term with :cmd:`Print` +(use here :opt:`Printing Matching`), then by printing the term with :cmd:`Print` if the term is a constant, or using the command :cmd:`Check`. The extended ``match`` still accepts an optional *elimination predicate* @@ -75,7 +75,7 @@ by: Multiple patterns ----------------- -Using multiple patterns in the definition of max lets us write: +Using multiple patterns in the definition of ``max`` lets us write: .. coqtop:: in undo @@ -273,7 +273,7 @@ This option (off by default) removes parameters from constructors in patterns: match l with | nil => nil | cons _ l' => l' - end) + end). Unset Asymmetric Patterns. Implicit arguments in patterns @@ -305,6 +305,8 @@ explicitations (as for terms 2.7.11). end). +.. _matching-dependent: + Matching objects of dependent types ----------------------------------- @@ -414,6 +416,7 @@ length, by writing I have a copy of :g:`b` in type :g:`listn 0` resp :g:`listn (S n')`. +.. _match-in-patterns: Patterns in ``in`` ~~~~~~~~~~~~~~~~~~ @@ -427,7 +430,7 @@ become impossible branches. In an impossible branch, you can answer anything but False_rect unit has the advantage to be subterm of anything. -To be concrete: the tail function can be written: +To be concrete: the ``tail`` function can be written: .. coqtop:: in @@ -588,24 +591,24 @@ generated expression and the original. Here is a summary of the error messages corresponding to each situation: -.. exn:: The constructor @ident expects @num arguments +.. exn:: The constructor @ident expects @num arguments. The variable ident is bound several times in pattern termFound a constructor of inductive type term while a constructor of term is expectedPatterns are incorrect (because constructors are not applied to the correct number of the arguments, because they are not linear or they are wrongly typed). -.. exn:: Non exhaustive pattern-matching +.. exn:: Non exhaustive pattern-matching. The pattern matching is not exhaustive. .. exn:: The elimination predicate term should be of arity @num (for non \ - dependent case) or @num (for dependent case) + dependent case) or @num (for dependent case). The elimination predicate provided to match has not the expected arity. .. exn:: Unable to infer a match predicate - Either there is a type incompatibility or the problem involves dependencies + Either there is a type incompatibility or the problem involves dependencies. There is a type mismatch between the different branches. The user should provide an elimination predicate. diff --git a/doc/sphinx/addendum/extraction.rst b/doc/sphinx/addendum/extraction.rst index d7f97edab1..cb93d48a41 100644 --- a/doc/sphinx/addendum/extraction.rst +++ b/doc/sphinx/addendum/extraction.rst @@ -1,16 +1,16 @@ -.. _extraction: - .. include:: ../replaces.rst -Extraction of programs in OCaml and Haskell -============================================ +.. _extraction: + +Extraction of programs in |OCaml| and Haskell +============================================= :Authors: Jean-Christophe Filliâtre and Pierre Letouzey We present here the |Coq| extraction commands, used to build certified and relatively efficient functional programs, extracting them from either |Coq| functions or |Coq| proofs of specifications. The -functional languages available as output are currently OCaml, Haskell +functional languages available as output are currently |OCaml|, Haskell and Scheme. In the following, "ML" will be used (abusively) to refer to any of the three. @@ -37,11 +37,11 @@ Generating ML Code The next two commands are meant to be used for rapid preview of extraction. They both display extracted term(s) inside |Coq|. -.. cmd:: Extraction @qualid. +.. cmd:: Extraction @qualid Extraction of the mentioned object in the |Coq| toplevel. -.. cmd:: Recursive Extraction @qualid ... @qualid. +.. cmd:: Recursive Extraction {+ @qualid } Recursive extraction of all the mentioned objects and all their dependencies in the |Coq| toplevel. @@ -49,7 +49,7 @@ extraction. They both display extracted term(s) inside |Coq|. All the following commands produce real ML files. User can choose to produce one monolithic file or one file per |Coq| library. -.. cmd:: Extraction "@file" @qualid ... @qualid. +.. cmd:: Extraction "@file" {+ @qualid } Recursive extraction of all the mentioned objects and all their dependencies in one monolithic `file`. @@ -57,43 +57,43 @@ produce one monolithic file or one file per |Coq| library. language to fulfill its syntactic conventions, keeping original names as much as possible. -.. cmd:: Extraction Library @ident. +.. cmd:: Extraction Library @ident Extraction of the whole |Coq| library ``ident.v`` to an ML module ``ident.ml``. In case of name clash, identifiers are here renamed using prefixes ``coq_`` or ``Coq_`` to ensure a session-independent renaming. -.. cmd:: Recursive Extraction Library @ident. +.. cmd:: Recursive Extraction Library @ident Extraction of the |Coq| library ``ident.v`` and all other modules ``ident.v`` depends on. -.. cmd:: Separate Extraction @qualid ... @qualid. +.. cmd:: Separate Extraction {+ @qualid } Recursive extraction of all the mentioned objects and all their dependencies, just as ``Extraction "file"``, but instead of producing one monolithic file, this command splits the produced code in separate ML files, one per corresponding Coq ``.v`` file. This command is hence quite similar to - ``Recursive Extraction Library``, except that only the needed + :cmd:`Recursive Extraction Library`, except that only the needed parts of Coq libraries are extracted instead of the whole. The naming convention in case of name clash is the same one as - ``Extraction Library``: identifiers are here renamed using prefixes + :cmd:`Extraction Library`: identifiers are here renamed using prefixes ``coq_`` or ``Coq_``. The following command is meant to help automatic testing of the extraction, see for instance the ``test-suite`` directory in the |Coq| sources. -.. cmd:: Extraction TestCompile @qualid ... @qualid. +.. cmd:: Extraction TestCompile {+ @qualid } All the mentioned objects and all their dependencies are extracted - to a temporary OCaml file, just as in ``Extraction "file"``. Then + to a temporary |OCaml| file, just as in ``Extraction "file"``. Then this temporary file and its signature are compiled with the same - OCaml compiler used to built |Coq|. This command succeeds only - if the extraction and the OCaml compilation succeed. It fails - if the current target language of the extraction is not OCaml. + |OCaml| compiler used to built |Coq|. This command succeeds only + if the extraction and the |OCaml| compilation succeed. It fails + if the current target language of the extraction is not |OCaml|. Extraction Options ------------------- @@ -102,26 +102,26 @@ Setting the target language ~~~~~~~~~~~~~~~~~~~~~~~~~~~ The ability to fix target language is the first and more important -of the extraction options. Default is ``Ocaml``. +of the extraction options. Default is ``OCaml``. -.. cmd:: Extraction Language Ocaml. -.. cmd:: Extraction Language Haskell. -.. cmd:: Extraction Language Scheme. +.. cmd:: Extraction Language OCaml +.. cmd:: Extraction Language Haskell +.. cmd:: Extraction Language Scheme Inlining and optimizations ~~~~~~~~~~~~~~~~~~~~~~~~~~~ -Since OCaml is a strict language, the extracted code has to +Since |OCaml| is a strict language, the extracted code has to be optimized in order to be efficient (for instance, when using induction principles we do not want to compute all the recursive calls but only the needed ones). So the extraction mechanism provides an automatic optimization routine that will be called each time the user -want to generate OCaml programs. The optimizations can be split in two +want to generate |OCaml| programs. The optimizations can be split in two groups: the type-preserving ones (essentially constant inlining and reductions) and the non type-preserving ones (some function abstractions of dummy types are removed when it is deemed safe in order to have more elegant types). Therefore some constants may not appear in the -resulting monolithic OCaml program. In the case of modular extraction, +resulting monolithic |OCaml| program. In the case of modular extraction, even if some inlining is done, the inlined constant are nevertheless printed, to ensure session-independent programs. @@ -131,14 +131,14 @@ order to produce more readable code. The type-preserving optimizations are controlled by the following |Coq| options: -.. opt:: Extraction Optimize. +.. opt:: Extraction Optimize Default is on. This controls all type-preserving optimizations made on the ML terms (mostly reduction of dummy beta/iota redexes, but also simplifications on Cases, etc). Turn this option off if you want a ML term as close as possible to the Coq term. -.. opt:: Extraction Conservative Types. +.. opt:: Extraction Conservative Types Default is off. This controls the non type-preserving optimizations made on ML terms (which try to avoid function abstraction of dummy @@ -146,7 +146,7 @@ The type-preserving optimizations are controlled by the following |Coq| options: implies that ``e':t'`` where ``e'`` and ``t'`` are the extracted code of ``e`` and ``t`` respectively. -.. opt:: Extraction KeepSingleton. +.. opt:: Extraction KeepSingleton Default is off. Normally, when the extraction of an inductive type produces a singleton type (i.e. a type with only one constructor, and @@ -155,7 +155,7 @@ The type-preserving optimizations are controlled by the following |Coq| options: The typical example is ``sig``. This option allows disabling this optimization when one wishes to preserve the inductive structure of types. -.. opt:: Extraction AutoInline. +.. opt:: Extraction AutoInline Default is on. The extraction mechanism inlines the bodies of some defined constants, according to some heuristics @@ -163,22 +163,22 @@ The type-preserving optimizations are controlled by the following |Coq| options: Those heuristics are not always perfect; if you want to disable this feature, turn this option off. -.. cmd:: Extraction Inline @qualid ... @qualid. +.. cmd:: Extraction Inline {+ @qualid } In addition to the automatic inline feature, the constants mentionned by this command will always be inlined during extraction. -.. cmd:: Extraction NoInline @qualid ... @qualid. +.. cmd:: Extraction NoInline {+ @qualid } Conversely, the constants mentionned by this command will never be inlined during extraction. -.. cmd:: Print Extraction Inline. +.. cmd:: Print Extraction Inline Prints the current state of the table recording the custom inlinings declared by the two previous commands. -.. cmd:: Reset Extraction Inline. +.. cmd:: Reset Extraction Inline Empties the table recording the custom inlinings (see the previous commands). @@ -213,7 +213,7 @@ code elimination performed during extraction, in a way which is independent but complementary to the main elimination principles of extraction (logical parts and types). -.. cmd:: Extraction Implicit @qualid [ @ident ... @ident ]. +.. cmd:: Extraction Implicit @qualid [ {+ @ident } ] This experimental command allows declaring some arguments of `qualid` as implicit, i.e. useless in extracted code and hence to @@ -223,11 +223,11 @@ principles of extraction (logical parts and types). by a number indicating its position, starting from 1. When an actual extraction takes place, an error is normally raised if the -``Extraction Implicit`` declarations cannot be honored, that is +:cmd:`Extraction Implicit` declarations cannot be honored, that is if any of the implicited variables still occurs in the final code. This behavior can be relaxed via the following option: -.. opt:: Extraction SafeImplicits. +.. opt:: Extraction SafeImplicits Default is on. When this option is off, a warning is emitted instead of an error if some implicited variables still occur in the @@ -253,21 +253,20 @@ a closed term, and of course the system cannot guess the program which realizes an axiom. Therefore, it is possible to tell the system what ML term corresponds to a given axiom. -.. cmd:: Extract Constant @qualid => @string. +.. cmd:: Extract Constant @qualid => @string Give an ML extraction for the given constant. The `string` may be an identifier or a quoted string. -.. cmd:: Extract Inlined Constant @qualid => @string. +.. cmd:: Extract Inlined Constant @qualid => @string Same as the previous one, except that the given ML terms will be inlined everywhere instead of being declared via a ``let``. .. note:: - - This command is sugar for an ``Extract Constant`` followed - by a ``Extraction Inline``. Hence a ``Reset Extraction Inline`` - will have an effect on the realized and inlined axiom. + This command is sugar for an :cmd:`Extract Constant` followed + by a :cmd:`Extraction Inline`. Hence a :cmd:`Reset Extraction Inline` + will have an effect on the realized and inlined axiom. .. caution:: It is the responsibility of the user to ensure that the ML terms given to realize the axioms do have the expected types. In @@ -286,7 +285,7 @@ Notice that in the case of type scheme axiom (i.e. whose type is an arity, that is a sequence of product finished by a sort), then some type variables have to be given (as quoted strings). The syntax is then: -.. cmdv:: Extract Constant @qualid @string ... @string => @string. +.. cmdv:: Extract Constant @qualid @string ... @string => @string The number of type variables is checked by the system. For example: @@ -295,7 +294,7 @@ The number of type variables is checked by the system. For example: Axiom Y : Set -> Set -> Set. Extract Constant Y "'a" "'b" => " 'a * 'b ". -Realizing an axiom via ``Extract Constant`` is only useful in the +Realizing an axiom via :cmd:`Extract Constant` is only useful in the case of an informative axiom (of sort ``Type`` or ``Set``). A logical axiom have no computational content and hence will not appears in extracted terms. But a warning is nonetheless issued if extraction encounters a @@ -315,7 +314,7 @@ The system also provides a mechanism to specify ML terms for inductive types and constructors. For instance, the user may want to use the ML native boolean type instead of |Coq| one. The syntax is the following: -.. cmd:: Extract Inductive @qualid => @string [ @string ... @string ]. +.. cmd:: Extract Inductive @qualid => @string [ {+ @string } ] Give an ML extraction for the given inductive type. You must specify extractions for the type itself (first `string`) and all its @@ -323,7 +322,7 @@ native boolean type instead of |Coq| one. The syntax is the following: the ML extraction must be an ML inductive datatype, and the native pattern-matching of the language will be used. -.. cmdv:: Extract Inductive @qualid => @string [ @string ... @string ] @string. +.. cmdv:: Extract Inductive @qualid => @string [ {+ @string } ] @string Same as before, with a final extra `string` that indicates how to perform pattern-matching over this inductive type. In this form, @@ -336,10 +335,10 @@ native boolean type instead of |Coq| one. The syntax is the following: argument is considered to have one unit argument, in order to block early evaluation of the branch: ``| O => bar`` leads to the functional form ``(fun () -> bar)``. For instance, when extracting ``nat`` - into OCaml ``int``, the code to provide has type: + into |OCaml| ``int``, the code to provide has type: ``(unit->'a)->(int->'a)->int->'a``. -.. caution:: As for ``Extract Constant``, this command should be used with care: +.. caution:: As for :cmd:`Extract Constant`, this command should be used with care: * The ML code provided by the user is currently **not** checked at all by extraction, even for syntax errors. @@ -347,17 +346,17 @@ native boolean type instead of |Coq| one. The syntax is the following: * Extracting an inductive type to a pre-existing ML inductive type is quite sound. But extracting to a general type (by providing an ad-hoc pattern-matching) will often **not** be fully rigorously - correct. For instance, when extracting ``nat`` to OCaml ``int``, + correct. For instance, when extracting ``nat`` to |OCaml| ``int``, it is theoretically possible to build ``nat`` values that are - larger than OCaml ``max_int``. It is the user's responsibility to + larger than |OCaml| ``max_int``. It is the user's responsibility to be sure that no overflow or other bad events occur in practice. * Translating an inductive type to an arbitrary ML type does **not** magically improve the asymptotic complexity of functions, even if the ML type is an efficient representation. For instance, when extracting - ``nat`` to OCaml ``int``, the function ``Nat.mul`` stays quadratic. + ``nat`` to |OCaml| ``int``, the function ``Nat.mul`` stays quadratic. It might be interesting to associate this translation with - some specific ``Extract Constant`` when primitive counterparts exist. + some specific :cmd:`Extract Constant` when primitive counterparts exist. Typical examples are the following: @@ -369,9 +368,9 @@ Typical examples are the following: .. note:: - When extracting to Ocaml, if an inductive constructor or type has arity 2 and + When extracting to |OCaml|, if an inductive constructor or type has arity 2 and the corresponding string is enclosed by parentheses, and the string meets - Ocaml's lexical criteria for an infix symbol, then the rest of the string is + |OCaml|'s lexical criteria for an infix symbol, then the rest of the string is used as infix constructor or type. .. coqtop:: in @@ -380,7 +379,7 @@ Typical examples are the following: Extract Inductive prod => "(*)" [ "(,)" ]. As an example of translation to a non-inductive datatype, let's turn -``nat`` into OCaml ``int`` (see caveat above): +``nat`` into |OCaml| ``int`` (see caveat above): .. coqtop:: in @@ -389,28 +388,28 @@ As an example of translation to a non-inductive datatype, let's turn Avoiding conflicts with existing filenames ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -When using ``Extraction Library``, the names of the extracted files +When using :cmd:`Extraction Library`, the names of the extracted files directly depends from the names of the |Coq| files. It may happen that these filenames are in conflict with already existing files, either in the standard library of the target language or in other code that is meant to be linked with the extracted code. -For instance the module ``List`` exists both in |Coq| and in OCaml. +For instance the module ``List`` exists both in |Coq| and in |OCaml|. It is possible to instruct the extraction not to use particular filenames. -.. cmd:: Extraction Blacklist @ident ... @ident. +.. cmd:: Extraction Blacklist {+ @ident } Instruct the extraction to avoid using these names as filenames for extracted code. -.. cmd:: Print Extraction Blacklist. +.. cmd:: Print Extraction Blacklist Show the current list of filenames the extraction should avoid. -.. cmd:: Reset Extraction Blacklist. +.. cmd:: Reset Extraction Blacklist Allow the extraction to use any filename. -For OCaml, a typical use of these commands is +For |OCaml|, a typical use of these commands is ``Extraction Blacklist String List``. Differences between |Coq| and ML type systems @@ -418,7 +417,7 @@ Differences between |Coq| and ML type systems Due to differences between |Coq| and ML type systems, some extracted programs are not directly typable in ML. -We now solve this problem (at least in OCaml) by adding +We now solve this problem (at least in |OCaml|) by adding when needed some unsafe casting ``Obj.magic``, which give a generic type ``'a`` to any term. @@ -432,7 +431,7 @@ function: Definition dp {A B:Type}(x:A)(y:B)(f:forall C:Type, C->C) := (f A x, f B y). -In Ocaml, for instance, the direct extracted term would be:: +In |OCaml|, for instance, the direct extracted term would be:: let dp x y f = Pair((f () x),(f () y)) @@ -455,12 +454,12 @@ of a constructor; for example: Inductive anything : Type := dummy : forall A:Set, A -> anything. which corresponds to the definition of an ML dynamic type. -In OCaml, we must cast any argument of the constructor dummy +In |OCaml|, we must cast any argument of the constructor dummy (no GADT are produced yet by the extraction). Even with those unsafe castings, you should never get error like ``segmentation fault``. In fact even if your program may seem -ill-typed to the Ocaml type-checker, it can't go wrong : it comes +ill-typed to the |OCaml| type-checker, it can't go wrong : it comes from a Coq well-typed terms, so for example inductive types will always have the correct number of arguments, etc. Of course, when launching manually some extracted function, you should apply it to arguments @@ -470,14 +469,14 @@ More details about the correctness of the extracted programs can be found in :cite:`Let02`. We have to say, though, that in most "realistic" programs, these problems do not -occur. For example all the programs of Coq library are accepted by the OCaml +occur. For example all the programs of Coq library are accepted by the |OCaml| type-checker without any ``Obj.magic`` (see examples below). Some examples ------------- We present here two examples of extractions, taken from the -|Coq| Standard Library. We choose OCaml as target language, +|Coq| Standard Library. We choose |OCaml| as target language, but all can be done in the other dialects with slight modifications. We then indicate where to find other examples and tests of extraction. @@ -493,7 +492,7 @@ This module contains a theorem ``eucl_dev``, whose type is:: where ``diveucl`` is a type for the pair of the quotient and the modulo, plus some logical assertions that disappear during extraction. -We can now extract this program to OCaml: +We can now extract this program to |OCaml|: .. coqtop:: none @@ -513,7 +512,7 @@ You can then copy-paste the output to a file ``euclid.ml`` or let Extraction "euclid" eucl_dev. -Let us play the resulting program (in an OCaml toplevel):: +Let us play the resulting program (in an |OCaml| toplevel):: #use "euclid.ml";; type nat = O | S of nat @@ -527,7 +526,7 @@ Let us play the resulting program (in an OCaml toplevel):: # eucl_dev (S (S O)) (S (S (S (S (S O)))));; - : diveucl = Divex (S (S O), S O) -It is easier to test on OCaml integers:: +It is easier to test on |OCaml| integers:: # let rec nat_of_int = function 0 -> O | n -> S (nat_of_int (n-1));; val nat_of_int : int -> nat = <fun> diff --git a/doc/sphinx/addendum/generalized-rewriting.rst b/doc/sphinx/addendum/generalized-rewriting.rst index da9e97e6fa..e10e16c107 100644 --- a/doc/sphinx/addendum/generalized-rewriting.rst +++ b/doc/sphinx/addendum/generalized-rewriting.rst @@ -1,14 +1,12 @@ -.. _generalizedrewriting: - ------------------------ - Generalized rewriting ------------------------ +.. include:: ../preamble.rst +.. include:: ../replaces.rst -:Author: Matthieu Sozeau +.. _generalizedrewriting: Generalized rewriting ===================== +:Author: Matthieu Sozeau This chapter presents the extension of several equality related tactics to work over user-defined structures (called setoids) that are @@ -181,7 +179,7 @@ A parametric relation :g:`Aeq: forall (y1 : β1 ... ym : βm )`, :g:`relation (A t1 ... tn)` over :g:`(A : αi -> ... αn -> Type)` can be declared with the following command: -.. cmd:: Add Parametric Relation (x1 : T1) ... (xn : Tk) : (A t1 ... tn) (Aeq t′1 ... t′m ) {? reflexivity proved by refl} {? symmetry proved by sym} {? transitivity proved by trans} as @ident. +.. cmd:: Add Parametric Relation (x1 : T1) ... (xn : Tk) : (A t1 ... tn) (Aeq t′1 ... t′m ) {? reflexivity proved by refl} {? symmetry proved by sym} {? transitivity proved by trans} as @ident after having required the ``Setoid`` module with the ``Require Setoid`` command. @@ -220,15 +218,15 @@ For Leibniz equality, we may declare: [reflexivity proved by @refl_equal A] ... -Some tactics (``reflexivity``, ``symmetry``, ``transitivity``) work only on +Some tactics (:tacn:`reflexivity`, :tacn:`symmetry`, :tacn:`transitivity`) work only on relations that respect the expected properties. The remaining tactics -(``replace``, ``rewrite`` and derived tactics such as ``autorewrite``) do not +(`replace`, :tacn:`rewrite` and derived tactics such as :tacn:`autorewrite`) do not require any properties over the relation. However, they are able to replace terms with related ones only in contexts that are syntactic compositions of parametric morphism instances declared with the following command. -.. cmd:: Add Parametric Morphism (x1 : T1 ) ... (xk : Tk ) : (f t1 ... tn ) with signature sig as @ident. +.. cmd:: Add Parametric Morphism (x1 : T1 ) ... (xk : Tk ) : (f t1 ... tn ) with signature sig as @ident The command declares ``f`` as a parametric morphism of signature ``sig``. The identifier ``id`` gives a unique name to the morphism and it is used as @@ -319,7 +317,7 @@ instance mechanism. The behavior on section close is to generalize the instances by the variables of the section (and possibly hypotheses used in the proofs of instance declarations) but not to export them in the rest of the development for proof search. One can use the -``Existing Instance`` command to do so outside the section, using the name of the +cmd:`Existing Instance` command to do so outside the section, using the name of the declared morphism suffixed by ``_Morphism``, or use the ``Global`` modifier for the corresponding class instance declaration (see :ref:`First Class Setoids and Morphisms <first-class-setoids-and-morphisms>`) at @@ -429,7 +427,7 @@ equality over ordered lists) ``set_eq ==> set_eq ==> set_eq`` ``multiset_eq ==> multiset_eq ==> multiset_eq`` (``multiset_eq`` being the equality over unordered lists). -To declare multiple signatures for a morphism, repeat the ``Add Morphism`` +To declare multiple signatures for a morphism, repeat the :cmd:`Add Morphism` command. When morphisms have multiple signatures it can be the case that a @@ -479,7 +477,7 @@ The declaration itself amounts to the definition of an object of the record type ``Coq.Classes.RelationClasses.Equivalence`` and a hint added to the ``typeclass_instances`` hint database. Morphism declarations are also instances of a type class defined in ``Classes.Morphisms``. See the -documentation on type classes :ref:`TODO-chapter-20-type-classes` +documentation on type classes :ref:`typeclasses` and the theories files in Classes for further explanations. One can inform the rewrite tactic about morphisms and relations just @@ -532,21 +530,26 @@ Tactics enabled on user provided relations The following tactics, all prefixed by ``setoid_``, deal with arbitrary registered relations and morphisms. Moreover, all the corresponding -unprefixed tactics (i.e. ``reflexivity``, ``symmetry``, ``transitivity``, -``replace``, ``rewrite``) have been extended to fall back to their prefixed +unprefixed tactics (i.e. :tacn:`reflexivity`, :tacn:`symmetry`, :tacn:`transitivity`, +:tacn:`replace`, :tacn:`rewrite`) have been extended to fall back to their prefixed counterparts when the relation involved is not Leibniz equality. Notice, however, that using the prefixed tactics it is possible to pass additional arguments such as ``using relation``. .. tacv:: setoid_reflexivity + :name: setoid_reflexivity .. tacv:: setoid_symmetry [in @ident] + :name: setoid_symmetry .. tacv:: setoid_transitivity + :name: setoid_transitivity .. tacv:: setoid_rewrite [@orientation] @term [at @occs] [in @ident] + :name: setoid_rewrite .. tacv:: setoid_replace @term with @term [in @ident] [using relation @term] [by @tactic] + :name: setoid_replace The ``using relation`` arguments cannot be passed to the unprefixed form. @@ -561,21 +564,23 @@ on a given type. Every derived tactic that is based on the unprefixed forms of the tactics considered above will also work up to user defined relations. -For instance, it is possible to register hints for ``autorewrite`` that +For instance, it is possible to register hints for :tacn:`autorewrite` that are not proof of Leibniz equalities. In particular it is possible to -exploit ``autorewrite`` to simulate normalization in a term rewriting +exploit :tacn:`autorewrite` to simulate normalization in a term rewriting system up to user defined equalities. Printing relations and morphisms ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -The ``Print Instances`` command can be used to show the list of currently +.. cmd:: Print Instances + +This command can be used to show the list of currently registered ``Reflexive`` (using ``Print Instances Reflexive``), ``Symmetric`` or ``Transitive`` relations, Equivalences, PreOrders, PERs, and Morphisms (implemented as ``Proper`` instances). When the rewriting tactics refuse to replace a term in a context because the latter is not a composition -of morphisms, the ``Print Instances`` commands can be useful to understand +of morphisms, the :cmd:`Print Instances` command can be useful to understand what additional morphisms should be registered. @@ -585,7 +590,7 @@ Deprecated syntax and backward incompatibilities Due to backward compatibility reasons, the following syntax for the declaration of setoids and morphisms is also accepted. -.. tacv:: Add Setoid @A @Aeq @ST as @ident +.. cmd:: Add Setoid @A @Aeq @ST as @ident where ``Aeq`` is a congruence relation without parameters, ``A`` is its carrier and ``ST`` is an object of type (``Setoid_Theory A Aeq``) (i.e. a record @@ -593,7 +598,8 @@ packing together the reflexivity, symmetry and transitivity lemmas). Notice that the syntax is not completely backward compatible since the identifier was not required. -.. cmd:: Add Morphism f : @ident. +.. cmd:: Add Morphism f : @ident + :name: Add Morphism The latter command also is restricted to the declaration of morphisms without parameters. It is not fully backward compatible since the @@ -607,11 +613,11 @@ Notice that several limitations of the old implementation have been lifted. In particular, it is now possible to declare several relations with the same carrier and several signatures for the same morphism. Moreover, it is now also possible to declare several morphisms having -the same signature. Finally, the replace and rewrite tactics can be +the same signature. Finally, the :tacn:`replace` and :tacn:`rewrite` tactics can be used to replace terms in contexts that were refused by the old implementation. As discussed in the next section, the semantics of the -new ``setoid_rewrite`` command differs slightly from the old one and -``rewrite``. +new :tacn:`setoid_rewrite` tactic differs slightly from the old one and +:tacn:`rewrite`. Extensions @@ -621,8 +627,9 @@ Extensions Rewriting under binders ~~~~~~~~~~~~~~~~~~~~~~~ -warning:: Due to compatibility issues, this feature is enabled only -when calling the ``setoid_rewrite`` tactics directly and not ``rewrite``. +.. warning:: + Due to compatibility issues, this feature is enabled only + when calling the :tacn:`setoid_rewrite` tactic directly and not :tacn:`rewrite`. To be able to rewrite under binding constructs, one must declare morphisms with respect to pointwise (setoid) equivalence of functions. @@ -669,12 +676,12 @@ where ``list_equiv`` implements an equivalence on lists parameterized by an equivalence on the elements. Note that when one does rewriting with a lemma under a binder using -``setoid_rewrite``, the application of the lemma may capture the bound +:tacn:`setoid_rewrite`, the application of the lemma may capture the bound variable, as the semantics are different from rewrite where the lemma -is first matched on the whole term. With the new ``setoid_rewrite``, +is first matched on the whole term. With the new :tacn:`setoid_rewrite`, matching is done on each subterm separately and in its local environment, and all matches are rewritten *simultaneously* by -default. The semantics of the previous ``setoid_rewrite`` implementation +default. The semantics of the previous :tacn:`setoid_rewrite` implementation can almost be recovered using the ``at 1`` modifier. @@ -707,22 +714,20 @@ defined constants as transparent by default. This may slow down the resolution due to a lot of unifications (all the declared ``Proper`` instances are tried at each node of the search tree). To speed it up, declare your constant as rigid for proof search using the command -``Typeclasses Opaque`` (see :ref:`TODO-20.6.7-typeclasses-transparency`). - +:cmd:`Typeclasses Opaque`. Strategies for rewriting ------------------------ - Definitions ~~~~~~~~~~~ -The generalized rewriting tactic is based on a set of strategies that -can be combined to obtain custom rewriting procedures. Its set of -strategies is based on Elan’s rewriting strategies :ref:`TODO-102-biblio`. Rewriting +The generalized rewriting tactic is based on a set of strategies that can be +combined to obtain custom rewriting procedures. Its set of strategies is based +on Elan’s rewriting strategies :cite:`Luttik97specificationof`. Rewriting strategies are applied using the tactic ``rewrite_strat s`` where ``s`` is a -strategy expression. Strategies are defined inductively as described -by the following grammar: +strategy expression. Strategies are defined inductively as described by the +following grammar: .. productionlist:: rewriting s, t, u : `strategy` @@ -808,11 +813,11 @@ strategy. Their counterparts ``bottomup`` and ``topdown`` perform as many rewritings as possible, starting from the bottom or the top of the term. -Hint databases created for ``autorewrite`` can also be used -by ``rewrite_strat`` using the ``hints`` strategy that applies any of the +Hint databases created for :tacn:`autorewrite` can also be used +by :tacn:`rewrite_strat` using the ``hints`` strategy that applies any of the lemmas at the current subterm. The ``terms`` strategy takes the lemma names directly as arguments. The ``eval`` strategy expects a reduction -expression (see :ref:`TODO-8.7-performing-computations`) and succeeds +expression (see :ref:`performingcomputations`) and succeeds if it reduces the subterm under consideration. The ``fold`` strategy takes a term ``c`` and tries to *unify* it to the current subterm, converting it to ``c`` on success, it is stronger than the tactic ``fold``. @@ -822,7 +827,8 @@ Usage ~~~~~ -.. tacv:: rewrite_strat @s [in @ident] +.. tacn:: rewrite_strat @s [in @ident] + :name: rewrite_strat Rewrite using the strategy s in hypothesis ident or the conclusion. diff --git a/doc/sphinx/addendum/implicit-coercions.rst b/doc/sphinx/addendum/implicit-coercions.rst index f5ca5be44a..09faa06765 100644 --- a/doc/sphinx/addendum/implicit-coercions.rst +++ b/doc/sphinx/addendum/implicit-coercions.rst @@ -1,7 +1,7 @@ -.. _implicitcoercions: - .. include:: ../replaces.rst +.. _implicitcoercions: + Implicit Coercions ==================== @@ -65,7 +65,7 @@ conditions holds: We then write :g:`f : C >-> D`. The restriction on the type of coercions is called *the uniform inheritance condition*. -.. note:: The abstract classe ``Sortclass`` can be used as a source class, but +.. note:: The abstract class ``Sortclass`` can be used as a source class, but the abstract class ``Funclass`` cannot. To coerce an object :g:`t:C t₁..tₙ` of ``C`` towards ``D``, we have to @@ -124,49 +124,49 @@ term consists of the successive application of its coercions. Declaration of Coercions ------------------------- -.. cmd:: Coercion @qualid : @class >-> @class. +.. cmd:: Coercion @qualid : @class >-> @class Declares the construction denoted by `qualid` as a coercion between the two given classes. - .. exn:: @qualid not declared - .. exn:: @qualid is already a coercion - .. exn:: Funclass cannot be a source class - .. exn:: @qualid is not a function - .. exn:: Cannot find the source class of @qualid - .. exn:: Cannot recognize @class as a source class of @qualid - .. exn:: @qualid does not respect the uniform inheritance condition + .. exn:: @qualid not declared. + .. exn:: @qualid is already a coercion. + .. exn:: Funclass cannot be a source class. + .. exn:: @qualid is not a function. + .. exn:: Cannot find the source class of @qualid. + .. exn:: Cannot recognize @class as a source class of @qualid. + .. exn:: @qualid does not respect the uniform inheritance condition. .. exn:: Found target class ... instead of ... - .. warn:: Ambigous path: + .. warn:: Ambiguous path. - When the coercion `qualid` is added to the inheritance graph, non - valid coercion paths are ignored; they are signaled by a warning - displaying these paths of the form :g:`[f₁;..;fₙ] : C >-> D`. + When the coercion :token:`qualid` is added to the inheritance graph, non + valid coercion paths are ignored; they are signaled by a warning + displaying these paths of the form :g:`[f₁;..;fₙ] : C >-> D`. - .. cmdv:: Local Coercion @qualid : @class >-> @class. + .. cmdv:: Local Coercion @qualid : @class >-> @class - Declares the construction denoted by `qualid` as a coercion local to - the current section. + Declares the construction denoted by `qualid` as a coercion local to + the current section. - .. cmdv:: Coercion @ident := @term. + .. cmdv:: Coercion @ident := @term - This defines `ident` just like ``Definition`` `ident` ``:=`` `term`, - and then declares `ident` as a coercion between it source and its target. + This defines `ident` just like ``Definition`` `ident` ``:=`` `term`, + and then declares `ident` as a coercion between it source and its target. - .. cmdv:: Coercion @ident := @term : @type. + .. cmdv:: Coercion @ident := @term : @type - This defines `ident` just like ``Definition`` `ident` : `type` ``:=`` `term`, - and then declares `ident` as a coercion between it source and its target. + This defines `ident` just like ``Definition`` `ident` : `type` ``:=`` `term`, + and then declares `ident` as a coercion between it source and its target. - .. cmdv:: Local Coercion @ident := @term. + .. cmdv:: Local Coercion @ident := @term - This defines `ident` just like ``Let`` `ident` ``:=`` `term`, - and then declares `ident` as a coercion between it source and its target. + This defines `ident` just like ``Let`` `ident` ``:=`` `term`, + and then declares `ident` as a coercion between it source and its target. Assumptions can be declared as coercions at declaration time. This extends the grammar of assumptions from -Figure :ref:`TODO-1.3-sentences-syntax` as follows: +Figure :ref:`vernacular` as follows: .. FIXME: @@ -186,7 +186,7 @@ assumptions are declared as coercions. Similarly, constructors of inductive types can be declared as coercions at definition time of the inductive type. This extends and modifies the -grammar of inductive types from Figure :ref:`TODO-1.3-sentences-syntax` as follows: +grammar of inductive types from Figure :ref:`vernacular` as follows: .. FIXME: @@ -202,7 +202,7 @@ grammar of inductive types from Figure :ref:`TODO-1.3-sentences-syntax` as follo Especially, if the extra ``>`` is present in a constructor declaration, this constructor is declared as a coercion. -.. cmd:: Identity Coercion @ident : @class >-> @class. +.. cmd:: Identity Coercion @ident : @class >-> @class If ``C`` is the source `class` and ``D`` the destination, we check that ``C`` is a constant with a body of the form @@ -211,13 +211,14 @@ declaration, this constructor is declared as a coercion. function with type :g:`forall (x₁:T₁)..(xₙ:Tₙ)(y:C x₁..xₙ),D t₁..tₘ`, and we declare it as an identity coercion between ``C`` and ``D``. - .. exn:: @class must be a transparent constant + .. exn:: @class must be a transparent constant. - .. cmdv:: Local Identity Coercion @ident : @ident >-> @ident. + .. cmdv:: Local Identity Coercion @ident : @ident >-> @ident Idem but locally to the current section. - .. cmdv:: SubClass @ident := @type. + .. cmdv:: SubClass @ident := @type + :name: SubClass If `type` is a class `ident'` applied to some arguments then `ident` is defined and an identity coercion of name @@ -228,7 +229,7 @@ declaration, this constructor is declared as a coercion. ``Identity Coercion`` `Id_ident_ident'` : `ident` ``>->`` `ident'`. - .. cmdv:: Local SubClass @ident := @type. + .. cmdv:: Local SubClass @ident := @type Same as before but locally to the current section. @@ -236,67 +237,67 @@ declaration, this constructor is declared as a coercion. Displaying Available Coercions ------------------------------- -.. cmd:: Print Classes. +.. cmd:: Print Classes Print the list of declared classes in the current context. -.. cmd:: Print Coercions. +.. cmd:: Print Coercions Print the list of declared coercions in the current context. -.. cmd:: Print Graph. +.. cmd:: Print Graph Print the list of valid coercion paths in the current context. -.. cmd:: Print Coercion Paths @class @class. +.. cmd:: Print Coercion Paths @class @class Print the list of valid coercion paths between the two given classes. Activating the Printing of Coercions ------------------------------------- -.. cmd:: Set Printing Coercions. +.. opt:: Printing Coercions + + When on, this option forces all the coercions to be printed. + By default, coercions are not printed. + +.. cmd:: Add Printing Coercion @qualid - This command forces all the coercions to be printed. - Conversely, to skip the printing of coercions, use - ``Unset Printing Coercions``. By default, coercions are not printed. + This command forces coercion denoted by :n:`@qualid` to be printed. + By default, a coercion is never printed. -.. cmd:: Add Printing Coercion @qualid. +.. cmd:: Remove Printing Coercion @qualid - This command forces coercion denoted by `qualid` to be printed. - To skip the printing of coercion `qualid`, use - ``Remove Printing Coercion`` `qualid`. By default, a coercion is never printed. + Use this command, to skip the printing of coercion :n:`@qualid`. +.. _coercions-classes-as-records: Classes as Records ------------------ -We allow the definition of *Structures with Inheritance* (or -classes as records) by extending the existing ``Record`` macro -(see Section :ref:`TODO-2.1-Record`). Its new syntax is: +We allow the definition of *Structures with Inheritance* (or classes as records) +by extending the existing :cmd:`Record` macro. Its new syntax is: -.. cmd:: Record {? >} @ident {? @binders} : @sort := {? @ident} { {+; @ident :{? >} @term } }. +.. cmdv:: Record {? >} @ident {? @binders} : @sort := {? @ident} { {+; @ident :{? >} @term } } - The first identifier `ident` is the name of the defined record and - `sort` is its type. The optional identifier after ``:=`` is the name - of the constuctor (it will be ``Build_``\ `ident` if not given). - The other identifiers are the names of the fields, and the `term` - are their respective types. If ``:>`` is used instead of ``:`` in - the declaration of a field, then the name of this field is automatically - declared as a coercion from the record name to the class of this - field type. Remark that the fields always verify the uniform - inheritance condition. If the optional ``>`` is given before the - record name, then the constructor name is automatically declared as - a coercion from the class of the last field type to the record name - (this may fail if the uniform inheritance condition is not - satisfied). + The first identifier `ident` is the name of the defined record and + `sort` is its type. The optional identifier after ``:=`` is the name + of the constuctor (it will be ``Build_``\ `ident` if not given). + The other identifiers are the names of the fields, and the `term` + are their respective types. If ``:>`` is used instead of ``:`` in + the declaration of a field, then the name of this field is automatically + declared as a coercion from the record name to the class of this + field type. Remark that the fields always verify the uniform + inheritance condition. If the optional ``>`` is given before the + record name, then the constructor name is automatically declared as + a coercion from the class of the last field type to the record name + (this may fail if the uniform inheritance condition is not + satisfied). -.. note:: +.. cmdv:: Structure {? >} @ident {? @binders} : @sort := {? @ident} { {+; @ident :{? >} @term } } + :name: Structure - The keyword ``Structure`` is a synonym of ``Record``. - -.. - FIXME: \comindex{Structure} + This is a synonym of :cmd:`Record`. Coercions and Sections @@ -312,20 +313,17 @@ coercions which do not verify the uniform inheritance condition any longer are also forgotten. Coercions and Modules ---------------------= - -From |Coq| version 8.3, the coercions present in a module are activated -only when the module is explicitly imported. Formerly, the coercions -were activated as soon as the module was required, whatever it was -imported or not. - -To recover the behavior of the versions of |Coq| prior to 8.3, use the -following command: +--------------------- -.. cmd:: Set Automatic Coercions Import. +.. opt:: Automatic Coercions Import -To cancel the effect of the option, use instead ``Unset Automatic Coercions Import``. + Since |Coq| version 8.3, the coercions present in a module are activated + only when the module is explicitly imported. Formerly, the coercions + were activated as soon as the module was required, whatever it was + imported or not. + This option makes it possible to recover the behavior of the versions of + |Coq| prior to 8.3. Examples -------- diff --git a/doc/sphinx/addendum/micromega.rst b/doc/sphinx/addendum/micromega.rst index e850587c8a..0e9c23b9bb 100644 --- a/doc/sphinx/addendum/micromega.rst +++ b/doc/sphinx/addendum/micromega.rst @@ -13,20 +13,19 @@ tactics for solving arithmetic goals over :math:`\mathbb{Z}`, :math:`\mathbb{Q}` It also possible to get the tactics for integers by a ``Require Import Lia``, rationals ``Require Import Lqa`` and reals ``Require Import Lra``. -+ ``lia`` is a decision procedure for linear integer arithmetic (see Section :ref:`lia <lia>`); -+ ``nia`` is an incomplete proof procedure for integer non-linear - arithmetic (see Section :ref:`nia <nia>`); -+ ``lra`` is a decision procedure for linear (real or rational) arithmetic - (see Section :ref:`lra <lra>`); -+ ``nra`` is an incomplete proof procedure for non-linear (real or - rational) arithmetic (see Section :ref:`nra <nra>`); -+ ``psatz D n`` where ``D`` is :math:`\mathbb{Z}` or :math:`\mathbb{Q}` or :math:`\mathbb{R}`, and ++ :tacn:`lia` is a decision procedure for linear integer arithmetic; ++ :tacn:`nia` is an incomplete proof procedure for integer non-linear + arithmetic; ++ :tacn:`lra` is a decision procedure for linear (real or rational) arithmetic; ++ :tacn:`nra` is an incomplete proof procedure for non-linear (real or + rational) arithmetic; ++ :tacn:`psatz` ``D n`` where ``D`` is :math:`\mathbb{Z}` or :math:`\mathbb{Q}` or :math:`\mathbb{R}`, and ``n`` is an optional integer limiting the proof search depth is an incomplete proof procedure for non-linear arithmetic. It is based on John Harrison’s HOL Light driver to the external prover `csdp` [#]_. Note that the `csdp` driver is generating a *proof cache* which makes it possible to rerun scripts - even without `csdp` (see Section :ref:`psatz <psatz>`). + even without `csdp`. The tactics solve propositional formulas parameterized by atomic arithmetic expressions interpreted over a domain :math:`D` ∈ {ℤ, ℚ, ℝ}. @@ -91,12 +90,13 @@ For each conjunct :math:`C_i`, the tactic calls a oracle which searches for expression* that is normalized by the ring tactic (see :ref:`theringandfieldtacticfamilies`) and checked to be :math:`-1`. -.. _lra: - `lra`: a decision procedure for linear real and rational arithmetic ------------------------------------------------------------------- -The `lra` tactic is searching for *linear* refutations using Fourier +.. tacn:: lra + :name: lra + +This tactic is searching for *linear* refutations using Fourier elimination [#]_. As a result, this tactic explores a subset of the *Cone* defined as @@ -107,16 +107,17 @@ The deductive power of `lra` is the combined deductive power of tactic *e.g.*, :math:`x = 10 * x / 10` is solved by `lra`. -.. _lia: - `lia`: a tactic for linear integer arithmetic --------------------------------------------- -The tactic lia offers an alternative to the omega and romega tactic -(see :ref:`omega`). Roughly speaking, the deductive power of lia is -the combined deductive power of `ring_simplify` and `omega`. However, it -solves linear goals that `omega` and `romega` do not solve, such as the -following so-called *omega nightmare* :cite:`TheOmegaPaper`. +.. tacn:: lia + :name: lia + +This tactic offers an alternative to the :tacn:`omega` and :tacn:`romega` +tactics. Roughly speaking, the deductive power of lia is the combined deductive +power of :tacn:`ring_simplify` and :tacn:`omega`. However, it solves linear +goals that :tacn:`omega` and :tacn:`romega` do not solve, such as the following +so-called *omega nightmare* :cite:`TheOmegaPaper`. .. coqtop:: in @@ -124,8 +125,8 @@ following so-called *omega nightmare* :cite:`TheOmegaPaper`. 27 <= 11 * x + 13 * y <= 45 -> -10 <= 7 * x - 9 * y <= 4 -> False. -The estimation of the relative efficiency of `lia` *vs* `omega` and `romega` -is under evaluation. +The estimation of the relative efficiency of :tacn:`lia` *vs* :tacn:`omega` and +:tacn:`romega` is under evaluation. High level view of `lia` ~~~~~~~~~~~~~~~~~~~~~~~~ @@ -149,9 +150,10 @@ are a way to take into account the discreteness of :math:`\mathbb{Z}` by roundin .. _ceil_thm: -**Theorem**. Let :math:`p` be an integer and :math:`c` a rational constant. Then +.. thm:: Bound on the ceiling function - :math:`p \ge c \rightarrow p \ge \lceil{c}\rceil` + Let :math:`p` be an integer and :math:`c` a rational constant. Then + :math:`p \ge c \rightarrow p \ge \lceil{c}\rceil`. For instance, from 2 x = 1 we can deduce @@ -182,12 +184,13 @@ Our current oracle tries to find an expression :math:`e` with a small range with an equation :math:`e = i` for :math:`i \in [c_1,c_2]` and recursively search for a proof. -.. _nra: - `nra`: a proof procedure for non-linear arithmetic -------------------------------------------------- -The `nra` tactic is an *experimental* proof procedure for non-linear +.. tacn:: nra + :name: nra + +This tactic is an *experimental* proof procedure for non-linear arithmetic. The tactic performs a limited amount of non-linear reasoning before running the linear prover of `lra`. This pre-processing does the following: @@ -202,21 +205,23 @@ does the following: After this pre-processing, the linear prover of `lra` searches for a proof by abstracting monomials by variables. -.. _nia: - `nia`: a proof procedure for non-linear integer arithmetic ---------------------------------------------------------- -The `nia` tactic is a proof procedure for non-linear integer arithmetic. +.. tacn:: nia + :name: nia + +This tactic is a proof procedure for non-linear integer arithmetic. It performs a pre-processing similar to `nra`. The obtained goal is solved using the linear integer prover `lia`. -.. _psatz: - `psatz`: a proof procedure for non-linear arithmetic ---------------------------------------------------- -The `psatz` tactic explores the :math:`\mathit{Cone}` by increasing degrees – hence the +.. tacn:: psatz + :name: psatz + +This tactic explores the :math:`\mathit{Cone}` by increasing degrees – hence the depth parameter :math:`n`. In theory, such a proof search is complete – if the goal is provable the search eventually stops. Unfortunately, the external oracle is using numeric (approximate) optimization techniques diff --git a/doc/sphinx/addendum/miscellaneous-extensions.rst b/doc/sphinx/addendum/miscellaneous-extensions.rst index b0343a8f01..b6c35d8fa7 100644 --- a/doc/sphinx/addendum/miscellaneous-extensions.rst +++ b/doc/sphinx/addendum/miscellaneous-extensions.rst @@ -3,23 +3,15 @@ .. _miscellaneousextensions: Miscellaneous extensions -======================= - -:Source: https://coq.inria.fr/distrib/current/refman/miscellaneous.html -:Converted by: Paul Steckler - -.. contents:: - :local: - :depth: 1 ----- +======================== Program derivation ------------------ +------------------ |Coq| comes with an extension called ``Derive``, which supports program derivation. Typically in the style of Bird and Meertens or derivations of program refinements. To use the Derive extension it must first be -required with ``Require Coq.Derive.Derive``. When the extension is loaded, +required with ``Require Coq.derive.Derive``. When the extension is loaded, it provides the following command: .. cmd:: Derive @ident SuchThat @term As @ident @@ -28,7 +20,7 @@ The first `ident` can appear in `term`. This command opens a new proof presenting the user with a goal for term in which the name `ident` is bound to an existential variable `?x` (formally, there are other goals standing for the existential variables but they are shelved, as -described in Section :ref:`TODO-8.17.4`). +described in :tacn:`shelve`). When the proof ends two constants are defined: diff --git a/doc/sphinx/addendum/nsatz.rst b/doc/sphinx/addendum/nsatz.rst index ef9b3505d4..387d614956 100644 --- a/doc/sphinx/addendum/nsatz.rst +++ b/doc/sphinx/addendum/nsatz.rst @@ -19,7 +19,7 @@ where :math:`P, Q, P₁,Q₁,\ldots,Pₛ, Qₛ` are polynomials and :math:`A` is domain, i.e. a commutative ring with no zero divisor. For example, :math:`A` can be :math:`\mathbb{R}`, :math:`\mathbb{Z}`, or :math:`\mathbb{Q}`. Note that the equality :math:`=` used in these goals can be -any setoid equality (see :ref:`TODO-27.2.2`) , not only Leibnitz equality. +any setoid equality (see :ref:`tactics-enabled-on-user-provided-relations`) , not only Leibnitz equality. It also proves formulas diff --git a/doc/sphinx/addendum/omega.rst b/doc/sphinx/addendum/omega.rst index 20e40c5507..80ce016200 100644 --- a/doc/sphinx/addendum/omega.rst +++ b/doc/sphinx/addendum/omega.rst @@ -12,24 +12,29 @@ This tactic does not need any parameter: .. tacn:: omega -``omega`` solves a goal in Presburger arithmetic, i.e. a universally +:tacn:`omega` solves a goal in Presburger arithmetic, i.e. a universally quantified formula made of equations and inequations. Equations may be specified either on the type ``nat`` of natural numbers or on the type ``Z`` of binary-encoded integer numbers. Formulas on ``nat`` are automatically injected into ``Z``. The procedure may use any hypothesis of the current proof session to solve the goal. -Multiplication is handled by ``omega`` but only goals where at +Multiplication is handled by :tacn:`omega` but only goals where at least one of the two multiplicands of products is a constant are solvable. This is the restriction meant by "Presburger arithmetic". If the tactic cannot solve the goal, it fails with an error message. In any case, the computation eventually stops. +.. tacv:: romega + :name: romega + + To be documented. + Arithmetical goals recognized by ``omega`` ------------------------------------------ -``omega`` applied only to quantifier-free formulas built from the +:tacn:`omega` applied only to quantifier-free formulas built from the connectors:: /\ \/ ~ -> @@ -38,11 +43,11 @@ on atomic formulas. Atomic formulas are built from the predicates:: = < <= > >= -on ``nat`` or ``Z``. In expressions of type ``nat``, ``omega`` recognizes:: +on ``nat`` or ``Z``. In expressions of type ``nat``, :tacn:`omega` recognizes:: + - * S O pred -and in expressions of type ``Z``, ``omega`` recognizes numeral constants and:: +and in expressions of type ``Z``, :tacn:`omega` recognizes numeral constants and:: + - * Z.succ Z.pred @@ -53,32 +58,32 @@ were arbitrary variables of type ``nat`` or ``Z``. Messages from ``omega`` ----------------------- -When ``omega`` does not solve the goal, one of the following errors +When :tacn:`omega` does not solve the goal, one of the following errors is generated: -.. exn:: omega can't solve this system +.. exn:: omega can't solve this system. This may happen if your goal is not quantifier-free (if it is - universally quantified, try ``intros`` first; if it contains - existentials quantifiers too, ``omega`` is not strong enough to solve your + universally quantified, try :tacn:`intros` first; if it contains + existentials quantifiers too, :tacn:`omega` is not strong enough to solve your goal). This may happen also if your goal contains arithmetical - operators unknown from ``omega``. Finally, your goal may be really + operators unknown from :tacn:`omega`. Finally, your goal may be really wrong! -.. exn:: omega: Not a quantifier-free goal +.. exn:: omega: Not a quantifier-free goal. If your goal is universally quantified, you should first apply - ``intro`` as many time as needed. + :tacn:`intro` as many times as needed. -.. exn:: omega: Unrecognized predicate or connective: @ident +.. exn:: omega: Unrecognized predicate or connective: @ident. .. exn:: omega: Unrecognized atomic proposition: ... -.. exn:: omega: Can't solve a goal with proposition variables +.. exn:: omega: Can't solve a goal with proposition variables. -.. exn:: omega: Unrecognized proposition +.. exn:: omega: Unrecognized proposition. -.. exn:: omega: Can't solve a goal with non-linear products +.. exn:: omega: Can't solve a goal with non-linear products. .. exn:: omega: Can't solve a goal with equality on type ... @@ -115,21 +120,23 @@ Options .. opt:: Stable Omega -This deprecated option (on by default) is for compatibility with Coq pre 8.5. It -resets internal name counters to make executions of ``omega`` independent. + .. deprecated:: 8.5 + + This deprecated option (on by default) is for compatibility with Coq pre 8.5. It + resets internal name counters to make executions of :tacn:`omega` independent. .. opt:: Omega UseLocalDefs -This option (on by default) allows ``omega`` to use the bodies of local -variables. + This option (on by default) allows :tacn:`omega` to use the bodies of local + variables. .. opt:: Omega System -This option (off by default) activate the printing of debug information + This option (off by default) activate the printing of debug information .. opt:: Omega Action -This option (off by default) activate the printing of debug information + This option (off by default) activate the printing of debug information Technical data -------------- @@ -149,7 +156,7 @@ Overview of the tactic Overview of the OMEGA decision procedure ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -The OMEGA decision procedure involved in the ``omega`` tactic uses +The OMEGA decision procedure involved in the :tacn:`omega` tactic uses a small subset of the decision procedure presented in :cite:`TheOmegaPaper` Here is an overview, look at the original paper for more information. diff --git a/doc/sphinx/addendum/parallel-proof-processing.rst b/doc/sphinx/addendum/parallel-proof-processing.rst index 8c1b9d152b..edb8676a5b 100644 --- a/doc/sphinx/addendum/parallel-proof-processing.rst +++ b/doc/sphinx/addendum/parallel-proof-processing.rst @@ -39,14 +39,14 @@ Proof annotations To process a proof asynchronously |Coq| needs to know the precise statement of the theorem without looking at the proof. This requires some annotations if the theorem is proved inside a Section (see -Section :ref:`TODO-2.4`). +Section :ref:`section-mechanism`). When a section ends, |Coq| looks at the proof object to decide which section variables are actually used and hence have to be quantified in the statement of the theorem. To avoid making the construction of proofs mandatory when ending a section, one can start each proof with -the ``Proof using`` command (Section :ref:`TODO-7.1.5`) that declares which section -variables the theorem uses. +the ``Proof using`` command (Section :ref:`proof-editing-mode`) that +declares which section variables the theorem uses. The presence of ``Proof`` using is needed to process proofs asynchronously in interactive mode. diff --git a/doc/sphinx/addendum/program.rst b/doc/sphinx/addendum/program.rst index eb50e52dc7..b685e68e43 100644 --- a/doc/sphinx/addendum/program.rst +++ b/doc/sphinx/addendum/program.rst @@ -135,7 +135,7 @@ support types, avoiding uses of proof-irrelevance that would come up when reasoning with equality on the subset types themselves. The next two commands are similar to their standard counterparts -Definition (see Section `TODO-1.3.2-Definition`_) and Fixpoint (see Section `TODO-1.3.4-Fixpoint`_) +:cmd:`Definition` and :cmd:`Fixpoint` in that they define constants. However, they may require the user to prove some goals to construct the final definitions. @@ -145,13 +145,14 @@ prove some goals to construct the final definitions. Program Definition ~~~~~~~~~~~~~~~~~~ -.. cmd:: Program Definition @ident := @term. +.. cmd:: Program Definition @ident := @term This command types the value term in Russell and generates proof obligations. Once solved using the commands shown below, it binds the final |Coq| term to the name ``ident`` in the environment. - .. exn:: ident already exists + .. exn:: @ident already exists. + :name: @ident already exists. (Program Definition) .. cmdv:: Program Definition @ident : @type := @term @@ -166,7 +167,7 @@ Program Definition .. exn:: In environment … the term: @term does not have type @type. Actually, it has type ... - .. cmdv:: Program Definition @ident @binders : @type := @term. + .. cmdv:: Program Definition @ident @binders : @type := @term This is equivalent to: @@ -174,14 +175,14 @@ Program Definition .. TODO refer to production in alias -See also: Sections `TODO-6.10.1-Opaque`_, `TODO-6.10.2-Transparent`_, `TODO-8.7.5-unfold`_ +See also: Sections :ref:`vernac-controlling-the-reduction-strategies`, :tacn:`unfold` .. _program_fixpoint: Program Fixpoint ~~~~~~~~~~~~~~~~ -.. cmd:: Program Fixpoint @ident @params {? {@order}} : @type := @term. +.. cmd:: Program Fixpoint @ident @params {? {@order}} : @type := @term The optional order annotation follows the grammar: @@ -196,7 +197,7 @@ The optional order annotation follows the grammar: + :g:`wf R x` which is equivalent to :g:`measure x (R)`. The structural fixpoint operator behaves just like the one of |Coq| (see -Section `TODO-1.3.4-Fixpoint`_), except it may also generate obligations. It works +:cmd:`Fixpoint`), except it may also generate obligations. It works with mutually recursive definitions too. .. coqtop:: reset none @@ -254,7 +255,7 @@ using the syntax: Program Lemma ~~~~~~~~~~~~~ -.. cmd:: Program Lemma @ident : @type. +.. cmd:: Program Lemma @ident : @type The Russell language can also be used to type statements of logical properties. It will generate obligations, try to solve them @@ -276,6 +277,7 @@ obligations (e.g. when defining mutually recursive blocks). The optional tactic is replaced by the default one if not specified. .. cmd:: {? Local|Global} Obligation Tactic := @tactic + :name: Obligation Tactic Sets the default obligation solving tactic applied to all obligations automatically, whether to solve them or when starting to prove one, @@ -348,7 +350,7 @@ Frequently Asked Questions --------------------------- -.. exn:: Ill-formed recursive definition +.. exn:: Ill-formed recursive definition. This error can happen when one tries to define a function by structural recursion on a subset object, which means the |Coq| function looks like: diff --git a/doc/sphinx/addendum/ring.rst b/doc/sphinx/addendum/ring.rst index b861892cbb..47d3a7d7cd 100644 --- a/doc/sphinx/addendum/ring.rst +++ b/doc/sphinx/addendum/ring.rst @@ -171,21 +171,21 @@ performs the simplification in the hypothesis named :n:`@ident`. Error messages: -.. exn:: not a valid ring equation +.. exn:: Not a valid ring equation. The conclusion of the goal is not provable in the corresponding ring theory. -.. exn:: arguments of ring_simplify do not have all the same type +.. exn:: Arguments of ring_simplify do not have all the same type. ``ring_simplify`` cannot simplify terms of several rings at the same time. Invoke the tactic once per ring structure. -.. exn:: cannot find a declared ring structure over @term +.. exn:: Cannot find a declared ring structure over @term. No ring has been declared for the type of the terms to be simplified. Use ``Add Ring`` first. -.. exn:: cannot find a declared ring structure for equality @term +.. exn:: Cannot find a declared ring structure for equality @term. Same as above is the case of the ``ring`` tactic. @@ -303,7 +303,7 @@ following property: The syntax for adding a new ring is -.. cmd:: Add Ring @ident : @term {? ( @ring_mod {* , @ring_mod } )}. +.. cmd:: Add Ring @ident : @term {? ( @ring_mod {* , @ring_mod } )} The :n:`@ident` is not relevant. It is just used for error messages. The :n:`@term` is a proof that the ring signature satisfies the (semi-)ring @@ -396,18 +396,18 @@ div :n:`@term` Error messages: -.. exn:: bad ring structure +.. exn:: Bad ring structure. The proof of the ring structure provided is not of the expected type. -.. exn:: bad lemma for decidability of equality +.. exn:: Bad lemma for decidability of equality. The equality function provided in the case of a computational ring has not the expected type. -.. exn:: ring operation should be declared as a morphism +.. exn:: Ring operation should be declared as a morphism. A setoid associated to the carrier of the ring structure has been found, but the ring operation should be declared as morphism. See :ref:`tactics-enabled-on-user-provided-relations`. @@ -656,7 +656,7 @@ zero for the correctness of the algorithm. The syntax for adding a new field is -.. cmd:: Add Field @ident : @term {? ( @field_mod {* , @field_mod } )}. +.. cmd:: Add Field @ident : @term {? ( @field_mod {* , @field_mod } )} The :n:`@ident` is not relevant. It is just used for error messages. :n:`@term` is a proof that the field signature satisfies the @@ -701,7 +701,7 @@ for |Coq|’s type-checker. Let us see why: At each step of rewriting, the whole context is duplicated in the proof term. Then, a tactic that does hundreds of rewriting generates huge proof terms. Since ``ACDSimpl`` was too slow, Samuel Boutin rewrote -it using reflection (see his article in TACS’97 [Bou97]_). Later, it +it using reflection (see :cite:`Bou97`). Later, it was rewritten by Patrick Loiseleur: the new tactic does not any more require ``ACDSimpl`` to compile and it makes use of |bdi|-reduction not only to replace the rewriting steps, but also to achieve the diff --git a/doc/sphinx/addendum/type-classes.rst b/doc/sphinx/addendum/type-classes.rst index becebb421b..6c7258f9c5 100644 --- a/doc/sphinx/addendum/type-classes.rst +++ b/doc/sphinx/addendum/type-classes.rst @@ -5,9 +5,6 @@ Type Classes ============ -:Source: https://coq.inria.fr/distrib/current/refman/type-classes.html -:Author: Matthieu Sozeau - This chapter presents a quick reference of the commands related to type classes. For an actual introduction to type classes, there is a description of the system :cite:`sozeau08` and the literature on type @@ -71,8 +68,8 @@ the remaining fields, e.g.: Defined. One has to take care that the transparency of every field is -determined by the transparency of the ``Instance`` proof. One can use -alternatively the ``Program Instance`` variant which has richer facilities +determined by the transparency of the :cmd:`Instance` proof. One can use +alternatively the :cmd:`Program Instance` variant which has richer facilities for dealing with obligations. @@ -151,11 +148,10 @@ database. Sections and contexts --------------------- -To ease the parametrization of developments by type classes, we -provide a new way to introduce variables into section contexts, -compatible with the implicit argument mechanism. The new command works -similarly to the ``Variables`` vernacular (:ref:`TODO-1.3.2-Definitions`), except it -accepts any binding context as argument. For example: +To ease the parametrization of developments by type classes, we provide a new +way to introduce variables into section contexts, compatible with the implicit +argument mechanism. The new command works similarly to the :cmd:`Variables` +vernacular, except it accepts any binding context as argument. For example: .. coqtop:: all @@ -273,12 +269,9 @@ the Existing Instance command to achieve the same effect. Summary of the commands ----------------------- +.. cmd:: Class @ident {? @binders} : {? @sort} := {? @ident} { {+; @ident :{? >} @term } } -.. _Class: - -.. cmd:: Class @ident {? @binders} : {? @sort} := {? @ident} { {+; @ident :{? >} @term } }. - - The ``Class`` command is used to declare a type class with parameters + The :cmd:`Class` command is used to declare a type class with parameters ``binders`` and fields the declared record fields. Variants: @@ -303,12 +296,10 @@ Variants: This variant declares a class a posteriori from a constant or inductive definition. No methods or instances are defined. -.. _Instance: - .. cmd:: Instance @ident {? @binders} : Class t1 … tn [| priority] := { field1 := b1 ; …; fieldi := bi } -The ``Instance`` command is used to declare a type class instance named -``ident`` of the class ``Class`` with parameters ``t1`` to ``tn`` and +The :cmd:`Instance` command is used to declare a type class instance named +``ident`` of the class :cmd:`Class` with parameters ``t1`` to ``tn`` and fields ``b1`` to ``bi``, where each field must be a declared field of the class. Missing fields must be filled in interactive proof mode. @@ -318,233 +309,235 @@ optional priority can be declared, 0 being the highest priority as for auto hints. If the priority is not specified, it defaults to the number of non-dependent binders of the instance. -Variants: - - -.. cmd:: Instance ident {? @binders} : forall {? @binders}, Class t1 … tn [| priority] := @term +.. cmdv:: Instance @ident {? @binders} : forall {? @binders}, Class t1 … tn [| priority] := @term This syntax is used for declaration of singleton class instances or for directly giving an explicit term of type ``forall binders, Class t1 … tn``. One need not even mention the unique field name for singleton classes. -.. cmd:: Global Instance +.. cmdv:: Global Instance One can use the ``Global`` modifier on instances declared in a section so that their generalization is automatically redeclared after the section is closed. -.. cmd:: Program Instance +.. cmdv:: Program Instance + :name: Program Instance - Switches the type-checking to Program (chapter :ref:`program`) and + Switches the type-checking to Program (chapter :ref:`programs`) and uses the obligation mechanism to manage missing fields. -.. cmd:: Declare Instance +.. cmdv:: Declare Instance + :name: Declare Instance In a Module Type, this command states that a corresponding concrete - instance should exist in any implementation of thisModule Type. This - is similar to the distinction betweenParameter vs. Definition, or - between Declare Module and Module. + instance should exist in any implementation of this Module Type. This + is similar to the distinction between :cmd:`Parameter` vs. :cmd:`Definition`, or + between :cmd:`Declare Module` and :cmd:`Module`. -Besides the ``Class`` and ``Instance`` vernacular commands, there are a +Besides the :cmd:`Class` and :cmd:`Instance` vernacular commands, there are a few other commands related to type classes. -.. _ExistingInstance: - -Existing Instance -~~~~~~~~~~~~~~~~~ - .. cmd:: Existing Instance {+ @ident} [| priority] -This commands adds an arbitrary list of constants whose type ends with -an applied type class to the instance database with an optional -priority. It can be used for redeclaring instances at the end of -sections, or declaring structure projections as instances. This is -equivalent to ``Hint Resolve ident : typeclass_instances``, except it -registers instances for ``Print Instances``. - -.. _Context: - -Context -~~~~~~~ + This commands adds an arbitrary list of constants whose type ends with + an applied type class to the instance database with an optional + priority. It can be used for redeclaring instances at the end of + sections, or declaring structure projections as instances. This is + equivalent to ``Hint Resolve ident : typeclass_instances``, except it + registers instances for :cmd:`Print Instances`. .. cmd:: Context @binders -Declares variables according to the given binding context, which might -use :ref:`implicit-generalization`. + Declares variables according to the given binding context, which might + use :ref:`implicit-generalization`. + +.. tacn:: typeclasses eauto + :name: typeclasses eauto + + This tactic uses a different resolution engine than :tacn:`eauto` and + :tacn:`auto`. The main differences are the following: + + + Contrary to :tacn:`eauto` and :tacn:`auto`, the resolution is done entirely in + the new proof engine (as of Coq 8.6), meaning that backtracking is + available among dependent subgoals, and shelving goals is supported. + typeclasses eauto is a multi-goal tactic. It analyses the dependencies + between subgoals to avoid backtracking on subgoals that are entirely + independent. + + + When called with no arguments, typeclasses eauto uses + the ``typeclass_instances`` database by default (instead of core). + Dependent subgoals are automatically shelved, and shelved goals can + remain after resolution ends (following the behavior of Coq 8.5). + + .. note:: + As of Coq 8.6, ``all:once (typeclasses eauto)`` faithfully + mimicks what happens during typeclass resolution when it is called + during refinement/type-inference, except that *only* declared class + subgoals are considered at the start of resolution during type + inference, while ``all`` can select non-class subgoals as well. It might + move to ``all:typeclasses eauto`` in future versions when the + refinement engine will be able to backtrack. + + + When called with specific databases (e.g. with), typeclasses eauto + allows shelved goals to remain at any point during search and treat + typeclasses goals like any other. + + + The transparency information of databases is used consistently for + all hints declared in them. It is always used when calling the + unifier. When considering the local hypotheses, we use the transparent + state of the first hint database given. Using an empty database + (created with :cmd:`Create HintDb` for example) with unfoldable variables and + constants as the first argument of typeclasses eauto hence makes + resolution with the local hypotheses use full conversion during + unification. + + + .. cmdv:: typeclasses eauto @num + + .. warning:: + The semantics for the limit :n:`@num` + is different than for auto. By default, if no limit is given the + search is unbounded. Contrary to auto, introduction steps (intro) are + counted, which might result in larger limits being necessary when + searching with typeclasses eauto than auto. + + .. cmdv:: typeclasses eauto with {+ @ident} + + This variant runs resolution with the given hint databases. It treats + typeclass subgoals the same as other subgoals (no shelving of + non-typeclass goals in particular). + +.. tacn:: autoapply @term with @ident + :name: autoapply + + The tactic autoapply applies a term using the transparency information + of the hint database ident, and does *no* typeclass resolution. This can + be used in :cmd:`Hint Extern`’s for typeclass instances (in the hint + database ``typeclass_instances``) to allow backtracking on the typeclass + subgoals created by the lemma application, rather than doing type class + resolution locally at the hint application time. +.. _TypeclassesTransparent: -.. _typeclasses-eauto: - -``typeclasses eauto`` -~~~~~~~~~~~~~~~~~~~~~ - -The ``typeclasses eauto`` tactic uses a different resolution engine than -eauto and auto. The main differences are the following: - -+ Contrary to ``eauto`` and ``auto``, the resolution is done entirely in - the new proof engine (as of Coq v8.6), meaning that backtracking is - available among dependent subgoals, and shelving goals is supported. - typeclasses eauto is a multi-goal tactic. It analyses the dependencies - between subgoals to avoid backtracking on subgoals that are entirely - independent. - -+ When called with no arguments, typeclasses eauto uses - thetypeclass_instances database by default (instead of core). - Dependent subgoals are automatically shelved, and shelved goals can - remain after resolution ends (following the behavior ofCoq 8.5). - *Note: * As of Coq 8.6, all:once (typeclasses eauto) faithfully - mimicks what happens during typeclass resolution when it is called - during refinement/type-inference, except that *only* declared class - subgoals are considered at the start of resolution during type - inference, while “all” can select non-class subgoals as well. It might - move to ``all:typeclasses eauto`` in future versions when the - refinement engine will be able to backtrack. - -+ When called with specific databases (e.g. with), typeclasses eauto - allows shelved goals to remain at any point during search and treat - typeclasses goals like any other. - -+ The transparency information of databases is used consistently for - all hints declared in them. It is always used when calling the - unifier. When considering the local hypotheses, we use the transparent - state of the first hint database given. Using an empty database - (created with Create HintDb for example) with unfoldable variables and - constants as the first argument of typeclasses eauto hence makes - resolution with the local hypotheses use full conversion during - unification. - - -Variants: - -#. ``typeclasses eauto [num]`` +Typeclasses Transparent, Typclasses Opaque +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - *Warning:* The semantics for the limit num - is different than for auto. By default, if no limit is given the - search is unbounded. Contrary to auto, introduction steps (intro) are - counted, which might result in larger limits being necessary when - searching with typeclasses eauto than auto. +.. cmd:: Typeclasses Transparent {+ @ident} -#. ``typeclasses eauto with {+ @ident}`` + This command defines makes the identifiers transparent during type class + resolution. - This variant runs resolution with the given hint databases. It treats - typeclass subgoals the same as other subgoals (no shelving of - non-typeclass goals in particular). +.. cmd:: Typeclasses Opaque {+ @ident} -.. _autoapply: + Make the identifiers opaque for typeclass search. It is useful when some + constants prevent some unifications and make resolution fail. It is also + useful to declare constants which should never be unfolded during + proof-search, like fixpoints or anything which does not look like an + abbreviation. This can additionally speed up proof search as the typeclass + map can be indexed by such rigid constants (see + :ref:`thehintsdatabasesforautoandeauto`). -``autoapply term with ident`` -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +By default, all constants and local variables are considered transparent. One +should take care not to make opaque any constant that is used to abbreviate a +type, like: -The tactic autoapply applies a term using the transparency information -of the hint database ident, and does *no* typeclass resolution. This can -be used in ``Hint Extern``’s for typeclass instances (in the hint -database ``typeclass_instances``) to allow backtracking on the typeclass -subgoals created by the lemma application, rather than doing type class -resolution locally at the hint application time. +:: -.. _TypeclassesTransparent: + relation A := A -> A -> Prop. -Typeclasses Transparent, Typclasses Opaque -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +This is equivalent to ``Hint Transparent, Opaque ident : typeclass_instances``. -.. cmd:: Typeclasses { Transparent | Opaque } {+ @ident} - This commands defines the transparency of the given identifiers - during type class resolution. It is useful when some constants - prevent some unifications and make resolution fail. It is also useful - to declare constants which should never be unfolded during - proof-search, like fixpoints or anything which does not look like an - abbreviation. This can additionally speed up proof search as the - typeclass map can be indexed by such rigid constants (see - :ref:`thehintsdatabasesforautoandeauto`). By default, all constants - and local variables are considered transparent. One should take care - not to make opaque any constant that is used to abbreviate a type, - like: +Options +~~~~~~~ -:: +.. opt:: Typeclasses Dependency Order - relation A := A -> A -> Prop. + This option (on by default since 8.6) respects the dependency order + between subgoals, meaning that subgoals which are depended on by other + subgoals come first, while the non-dependent subgoals were put before + the dependent ones previously (Coq 8.5 and below). This can result in + quite different performance behaviors of proof search. -This is equivalent to ``Hint Transparent, Opaque ident : typeclass_instances``. +.. opt:: Typeclasses Filtered Unification -Set Typeclasses Dependency Order -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + This option, available since Coq 8.6 and off by default, switches the + hint application procedure to a filter-then-unify strategy. To apply a + hint, we first check that the goal *matches* syntactically the + inferred or specified pattern of the hint, and only then try to + *unify* the goal with the conclusion of the hint. This can drastically + improve performance by calling unification less often, matching + syntactic patterns being very quick. This also provides more control + on the triggering of instances. For example, forcing a constant to + explicitely appear in the pattern will make it never apply on a goal + where there is a hole in that place. -This option (on by default since 8.6) respects the dependency order -between subgoals, meaning that subgoals which are depended on by other -subgoals come first, while the non-dependent subgoals were put before -the dependent ones previously (Coq v8.5 and below). This can result in -quite different performance behaviors of proof search. +.. opt:: Typeclasses Limit Intros -Set Typeclasses Filtered Unification -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + This option (on by default) controls the ability to apply hints while + avoiding (functional) eta-expansions in the generated proof term. It + does so by allowing hints that conclude in a product to apply to a + goal with a matching product directly, avoiding an introduction. + *Warning:* this can be expensive as it requires rebuilding hint + clauses dynamically, and does not benefit from the invertibility + status of the product introduction rule, resulting in potentially more + expensive proof-search (i.e. more useless backtracking). -This option, available since Coq 8.6 and off by default, switches the -hint application procedure to a filter-then-unify strategy. To apply a -hint, we first check that the goal *matches* syntactically the -inferred or specified pattern of the hint, and only then try to -*unify* the goal with the conclusion of the hint. This can drastically -improve performance by calling unification less often, matching -syntactic patterns being very quick. This also provides more control -on the triggering of instances. For example, forcing a constant to -explicitely appear in the pattern will make it never apply on a goal -where there is a hole in that place. +.. opt:: Typeclass Resolution For Conversion -Set Typeclasses Limit Intros -~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + This option (on by default) controls the use of typeclass resolution + when a unification problem cannot be solved during elaboration/type- + inference. With this option on, when a unification fails, typeclass + resolution is tried before launching unification once again. -This option (on by default) controls the ability to apply hints while -avoiding (functional) eta-expansions in the generated proof term. It -does so by allowing hints that conclude in a product to apply to a -goal with a matching product directly, avoiding an introduction. -*Warning:* this can be expensive as it requires rebuilding hint -clauses dynamically, and does not benefit from the invertibility -status of the product introduction rule, resulting in potentially more -expensive proof-search (i.e. more useless backtracking). +.. opt:: Typeclasses Strict Resolution + Typeclass declarations introduced when this option is set have a + stricter resolution behavior (the option is off by default). When + looking for unifications of a goal with an instance of this class, we + “freeze” all the existentials appearing in the goals, meaning that + they are considered rigid during unification and cannot be + instantiated. -Set Typeclass Resolution For Conversion -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -This option (on by default) controls the use of typeclass resolution -when a unification problem cannot be solved during elaboration/type- -inference. With this option on, when a unification fails, typeclass -resolution is tried before launching unification once again. +.. opt:: Typeclasses Unique Solutions + When a typeclass resolution is launched we ensure that it has a single + solution or fail. This ensures that the resolution is canonical, but + can make proof search much more expensive. -Set Typeclasses Strict Resolution -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -Typeclass declarations introduced when this option is set have a -stricter resolution behavior (the option is off by default). When -looking for unifications of a goal with an instance of this class, we -“freeze” all the existentials appearing in the goals, meaning that -they are considered rigid during unification and cannot be -instantiated. +.. opt:: Typeclasses Unique Instances + Typeclass declarations introduced when this option is set have a more + efficient resolution behavior (the option is off by default). When a + solution to the typeclass goal of this class is found, we never + backtrack on it, assuming that it is canonical. -Set Typeclasses Unique Solutions -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.. opt:: Typeclasses Debug {? Verbosity @num} -When a typeclass resolution is launched we ensure that it has a single -solution or fail. This ensures that the resolution is canonical, but -can make proof search much more expensive. + These options allow to see the resolution steps of typeclasses that are + performed during search. The ``Debug`` option is synonymous to ``Debug + Verbosity 1``, and ``Debug Verbosity 2`` provides more information + (tried tactics, shelving of goals, etc…). +.. opt:: Refine Instance Mode -Set Typeclasses Unique Instances -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + This option allows to switch the behavior of instance declarations made through + the Instance command. -Typeclass declarations introduced when this option is set have a more -efficient resolution behavior (the option is off by default). When a -solution to the typeclass goal of this class is found, we never -backtrack on it, assuming that it is canonical. + + When it is on (the default), instances that have unsolved holes in + their proof-term silently open the proof mode with the remaining + obligations to prove. + + When it is off, they fail with an error instead. Typeclasses eauto `:=` ~~~~~~~~~~~~~~~~~~~~~~ @@ -561,27 +554,3 @@ Typeclasses eauto `:=` default) or breadth-first search. + ``depth`` This sets the depth limit of the search. - - -Set Typeclasses Debug -~~~~~~~~~~~~~~~~~~~~~ - -.. cmd:: Set Typeclasses Debug {? Verbosity @num} - -These options allow to see the resolution steps of typeclasses that are -performed during search. The ``Debug`` option is synonymous to ``Debug -Verbosity 1``, and ``Debug Verbosity 2`` provides more information -(tried tactics, shelving of goals, etc…). - - -Set Refine Instance Mode -~~~~~~~~~~~~~~~~~~~~~~~~ - -The option Refine Instance Mode allows to switch the behavior of -instance declarations made through the Instance command. - -+ When it is on (the default), instances that have unsolved holes in - their proof-term silently open the proof mode with the remaining - obligations to prove. - -+ When it is off, they fail with an error instead. diff --git a/doc/sphinx/addendum/universe-polymorphism.rst b/doc/sphinx/addendum/universe-polymorphism.rst new file mode 100644 index 0000000000..6e7ccba63c --- /dev/null +++ b/doc/sphinx/addendum/universe-polymorphism.rst @@ -0,0 +1,445 @@ +.. include:: ../replaces.rst + +.. _polymorphicuniverses: + +Polymorphic Universes +====================== + +:Author: Matthieu Sozeau + +General Presentation +--------------------- + +.. warning:: + + The status of Universe Polymorphism is experimental. + +This section describes the universe polymorphic extension of |Coq|. +Universe polymorphism makes it possible to write generic definitions +making use of universes and reuse them at different and sometimes +incompatible universe levels. + +A standard example of the difference between universe *polymorphic* +and *monomorphic* definitions is given by the identity function: + +.. coqtop:: in + + Definition identity {A : Type} (a : A) := a. + +By default, constant declarations are monomorphic, hence the identity +function declares a global universe (say ``Top.1``) for its domain. +Subsequently, if we try to self-apply the identity, we will get an +error: + +.. coqtop:: all + + Fail Definition selfid := identity (@identity). + +Indeed, the global level ``Top.1`` would have to be strictly smaller than +itself for this self-application to typecheck, as the type of +:g:`(@identity)` is :g:`forall (A : Type@{Top.1}), A -> A` whose type is itself +:g:`Type@{Top.1+1}`. + +A universe polymorphic identity function binds its domain universe +level at the definition level instead of making it global. + +.. coqtop:: in + + Polymorphic Definition pidentity {A : Type} (a : A) := a. + +.. coqtop:: all + + About pidentity. + +It is then possible to reuse the constant at different levels, like +so: + +.. coqtop:: in + + Definition selfpid := pidentity (@pidentity). + +Of course, the two instances of :g:`pidentity` in this definition are +different. This can be seen when the :opt:`Printing Universes` option is on: + +.. coqtop:: none + + Set Printing Universes. + +.. coqtop:: all + + Print selfpid. + +Now :g:`pidentity` is used at two different levels: at the head of the +application it is instantiated at ``Top.3`` while in the argument position +it is instantiated at ``Top.4``. This definition is only valid as long as +``Top.4`` is strictly smaller than ``Top.3``, as show by the constraints. Note +that this definition is monomorphic (not universe polymorphic), so the +two universes (in this case ``Top.3`` and ``Top.4``) are actually global +levels. + +When printing :g:`pidentity`, we can see the universes it binds in +the annotation :g:`@{Top.2}`. Additionally, when +:opt:`Printing Universes` is on we print the "universe context" of +:g:`pidentity` consisting of the bound universes and the +constraints they must verify (for :g:`pidentity` there are no constraints). + +Inductive types can also be declared universes polymorphic on +universes appearing in their parameters or fields. A typical example +is given by monoids: + +.. coqtop:: in + + Polymorphic Record Monoid := { mon_car :> Type; mon_unit : mon_car; + mon_op : mon_car -> mon_car -> mon_car }. + +.. coqtop:: in + + Print Monoid. + +The Monoid's carrier universe is polymorphic, hence it is possible to +instantiate it for example with :g:`Monoid` itself. First we build the +trivial unit monoid in :g:`Set`: + +.. coqtop:: in + + Definition unit_monoid : Monoid := + {| mon_car := unit; mon_unit := tt; mon_op x y := tt |}. + +From this we can build a definition for the monoid of :g:`Set`\-monoids +(where multiplication would be given by the product of monoids). + +.. coqtop:: in + + Polymorphic Definition monoid_monoid : Monoid. + refine (@Build_Monoid Monoid unit_monoid (fun x y => x)). + Defined. + +.. coqtop:: all + + Print monoid_monoid. + +As one can see from the constraints, this monoid is “large”, it lives +in a universe strictly higher than :g:`Set`. + +Polymorphic, Monomorphic +------------------------- + +.. cmd:: Polymorphic @definition + + As shown in the examples, polymorphic definitions and inductives can be + declared using the ``Polymorphic`` prefix. + +.. opt:: Universe Polymorphism + + Once enabled, this option will implicitly prepend ``Polymorphic`` to any + definition of the user. + +.. cmd:: Monomorphic @definition + + When the :opt:`Universe Polymorphism` option is set, to make a definition + producing global universe constraints, one can use the ``Monomorphic`` prefix. + +Many other commands support the ``Polymorphic`` flag, including: + +.. TODO add links on each of these? + +- ``Lemma``, ``Axiom``, and all the other “definition” keywords support + polymorphism. + +- ``Variables``, ``Context``, ``Universe`` and ``Constraint`` in a section support + polymorphism. This means that the universe variables (and associated + constraints) are discharged polymorphically over definitions that use + them. In other words, two definitions in the section sharing a common + variable will both get parameterized by the universes produced by the + variable declaration. This is in contrast to a “mononorphic” variable + which introduces global universes and constraints, making the two + definitions depend on the *same* global universes associated to the + variable. + +- :cmd:`Hint Resolve` and :cmd:`Hint Rewrite` will use the auto/rewrite hint + polymorphically, not at a single instance. + +Cumulative, NonCumulative +------------------------- + +Polymorphic inductive types, coinductive types, variants and records can be +declared cumulative using the :g:`Cumulative` prefix. + +.. cmd:: Cumulative @inductive + + Declares the inductive as cumulative + +Alternatively, there is an option :opt:`Polymorphic Inductive +Cumulativity` which when set, makes all subsequent *polymorphic* +inductive definitions cumulative. When set, inductive types and the +like can be enforced to be non-cumulative using the :g:`NonCumulative` +prefix. + +.. cmd:: NonCumulative @inductive + + Declares the inductive as non-cumulative + +.. opt:: Polymorphic Inductive Cumulativity + + When this option is on, it sets all following polymorphic inductive + types as cumulative (it is off by default). + +Consider the examples below. + +.. coqtop:: in + + Polymorphic Cumulative Inductive list {A : Type} := + | nil : list + | cons : A -> list -> list. + +.. coqtop:: all + + Print list. + +When printing :g:`list`, the universe context indicates the subtyping +constraints by prefixing the level names with symbols. + +Because inductive subtypings are only produced by comparing inductives +to themselves with universes changed, they amount to variance +information: each universe is either invariant, covariant or +irrelevant (there are no contravariant subtypings in Coq), +respectively represented by the symbols `=`, `+` and `*`. + +Here we see that :g:`list` binds an irrelevant universe, so any two +instances of :g:`list` are convertible: :math:`E[Γ] ⊢ \mathsf{list}@\{i\}~A +=_{βδιζη} \mathsf{list}@\{j\}~B` whenever :math:`E[Γ] ⊢ A =_{βδιζη} B` and +this applies also to their corresponding constructors, when +they are comparable at the same type. + +See :ref:`Conversion-rules` for more details on convertibility and subtyping. +The following is an example of a record with non-trivial subtyping relation: + +.. coqtop:: all + + Polymorphic Cumulative Record packType := {pk : Type}. + +:g:`packType` binds a covariant universe, i.e. + +.. math:: + + E[Γ] ⊢ \mathsf{packType}@\{i\} =_{βδιζη} + \mathsf{packType}@\{j\}~\mbox{ whenever }~i ≤ j + +Cumulative inductive types, coninductive types, variants and records +only make sense when they are universe polymorphic. Therefore, an +error is issued whenever the user uses the :g:`Cumulative` or +:g:`NonCumulative` prefix in a monomorphic context. +Notice that this is not the case for the option :opt:`Polymorphic Inductive Cumulativity`. +That is, this option, when set, makes all subsequent *polymorphic* +inductive declarations cumulative (unless, of course the :g:`NonCumulative` prefix is used) +but has no effect on *monomorphic* inductive declarations. + +Consider the following examples. + +.. coqtop:: all reset + + Monomorphic Cumulative Inductive Unit := unit. + +.. coqtop:: all reset + + Monomorphic NonCumulative Inductive Unit := unit. + +.. coqtop:: all reset + + Set Polymorphic Inductive Cumulativity. + Inductive Unit := unit. + +An example of a proof using cumulativity +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +.. coqtop:: in + + Set Universe Polymorphism. + Set Polymorphic Inductive Cumulativity. + + Inductive eq@{i} {A : Type@{i}} (x : A) : A -> Type@{i} := eq_refl : eq x x. + + Definition funext_type@{a b e} (A : Type@{a}) (B : A -> Type@{b}) + := forall f g : (forall a, B a), + (forall x, eq@{e} (f x) (g x)) + -> eq@{e} f g. + + Section down. + Universes a b e e'. + Constraint e' < e. + Lemma funext_down {A B} + (H : @funext_type@{a b e} A B) : @funext_type@{a b e'} A B. + Proof. + exact H. + Defined. + End down. + +Cumulativity Weak Constraints +----------------------------- + +.. opt:: Cumulativity Weak Constraints + +This option, on by default, causes "weak" constraints to be produced +when comparing universes in an irrelevant position. Processing weak +constraints is delayed until minimization time. A weak constraint +between `u` and `v` when neither is smaller than the other and +one is flexible causes them to be unified. Otherwise the constraint is +silently discarded. + +This heuristic is experimental and may change in future versions. +Disabling weak constraints is more predictable but may produce +arbitrary numbers of universes. + + +Global and local universes +--------------------------- + +Each universe is declared in a global or local environment before it +can be used. To ensure compatibility, every *global* universe is set +to be strictly greater than :g:`Set` when it is introduced, while every +*local* (i.e. polymorphically quantified) universe is introduced as +greater or equal to :g:`Set`. + + +Conversion and unification +--------------------------- + +The semantics of conversion and unification have to be modified a +little to account for the new universe instance arguments to +polymorphic references. The semantics respect the fact that +definitions are transparent, so indistinguishable from their bodies +during conversion. + +This is accomplished by changing one rule of unification, the first- +order approximation rule, which applies when two applicative terms +with the same head are compared. It tries to short-cut unfolding by +comparing the arguments directly. In case the constant is universe +polymorphic, we allow this rule to fire only when unifying the +universes results in instantiating a so-called flexible universe +variables (not given by the user). Similarly for conversion, if such +an equation of applicative terms fail due to a universe comparison not +being satisfied, the terms are unfolded. This change implies that +conversion and unification can have different unfolding behaviors on +the same development with universe polymorphism switched on or off. + + +Minimization +------------- + +Universe polymorphism with cumulativity tends to generate many useless +inclusion constraints in general. Typically at each application of a +polymorphic constant :g:`f`, if an argument has expected type :g:`Type@{i}` +and is given a term of type :g:`Type@{j}`, a :math:`j ≤ i` constraint will be +generated. It is however often the case that an equation :math:`j = i` would +be more appropriate, when :g:`f`\'s universes are fresh for example. +Consider the following example: + +.. coqtop:: none + + Polymorphic Definition pidentity {A : Type} (a : A) := a. + Set Printing Universes. + +.. coqtop:: in + + Definition id0 := @pidentity nat 0. + +.. coqtop:: all + + Print id0. + +This definition is elaborated by minimizing the universe of :g:`id0` to +level :g:`Set` while the more general definition would keep the fresh level +:g:`i` generated at the application of :g:`id` and a constraint that :g:`Set` :math:`≤ i`. +This minimization process is applied only to fresh universe variables. +It simply adds an equation between the variable and its lower bound if +it is an atomic universe (i.e. not an algebraic max() universe). + +.. opt:: Universe Minimization ToSet + + Turning this option off (it is on by default) disallows minimization + to the sort :g:`Set` and only collapses floating universes between + themselves. + + +Explicit Universes +------------------- + +The syntax has been extended to allow users to explicitly bind names +to universes and explicitly instantiate polymorphic definitions. + +.. cmd:: Universe @ident + + In the monorphic case, this command declares a new global universe + named :g:`ident`, which can be referred to using its qualified name + as well. Global universe names live in a separate namespace. The + command supports the polymorphic flag only in sections, meaning the + universe quantification will be discharged on each section definition + independently. One cannot mix polymorphic and monomorphic + declarations in the same section. + + +.. cmd:: Constraint @ident @ord @ident + + This command declares a new constraint between named universes. The + order relation :n:`@ord` can be one of :math:`<`, :math:`≤` or :math:`=`. If consistent, the constraint + is then enforced in the global environment. Like ``Universe``, it can be + used with the ``Polymorphic`` prefix in sections only to declare + constraints discharged at section closing time. One cannot declare a + global constraint on polymorphic universes. + + .. exn:: Undeclared universe @ident. + + .. exn:: Universe inconsistency. + + +Polymorphic definitions +~~~~~~~~~~~~~~~~~~~~~~~ + +For polymorphic definitions, the declaration of (all) universe levels +introduced by a definition uses the following syntax: + +.. coqtop:: in + + Polymorphic Definition le@{i j} (A : Type@{i}) : Type@{j} := A. + +.. coqtop:: all + + Print le. + +During refinement we find that :g:`j` must be larger or equal than :g:`i`, as we +are using :g:`A : Type@{i} <= Type@{j}`, hence the generated constraint. At the +end of a definition or proof, we check that the only remaining +universes are the ones declared. In the term and in general in proof +mode, introduced universe names can be referred to in terms. Note that +local universe names shadow global universe names. During a proof, one +can use :cmd:`Show Universes` to display the current context of universes. + +Definitions can also be instantiated explicitly, giving their full +instance: + +.. coqtop:: all + + Check (pidentity@{Set}). + Monomorphic Universes k l. + Check (le@{k l}). + +User-named universes and the anonymous universe implicitly attached to +an explicit :g:`Type` are considered rigid for unification and are never +minimized. Flexible anonymous universes can be produced with an +underscore or by omitting the annotation to a polymorphic definition. + +.. coqtop:: all + + Check (fun x => x) : Type -> Type. + Check (fun x => x) : Type -> Type@{_}. + + Check le@{k _}. + Check le. + +.. opt:: Strict Universe Declaration. + + Turning this option off allows one to freely use + identifiers for universes without declaring them first, with the + semantics that the first use declares it. In this mode, the universe + names are not associated with the definition or proof once it has been + defined. This is meant mainly for debugging purposes. diff --git a/doc/sphinx/biblio.bib b/doc/sphinx/biblio.bib index 247f32103c..3e988709c5 100644 --- a/doc/sphinx/biblio.bib +++ b/doc/sphinx/biblio.bib @@ -3,47 +3,6 @@ @String{lnai = "Lecture Notes in Artificial Intelligence"} @String{SV = "{Sprin-ger-Verlag}"} -@InProceedings{Aud91, - author = {Ph. Audebaud}, - booktitle = {Proceedings of the sixth Conf. on Logic in Computer Science.}, - publisher = {IEEE}, - title = {Partial {Objects} in the {Calculus of Constructions}}, - year = {1991} -} - -@PhDThesis{Aud92, - author = {Ph. Audebaud}, - school = {{Universit\'e} Bordeaux I}, - title = {Extension du Calcul des Constructions par Points fixes}, - year = {1992} -} - -@InProceedings{Audebaud92b, - author = {Ph. Audebaud}, - booktitle = {{Proceedings of the 1992 Workshop on Types for Proofs and Programs}}, - editor = {{B. Nordstr\"om and K. Petersson and G. Plotkin}}, - note = {Also Research Report LIP-ENS-Lyon}, - pages = {21--34}, - title = {{CC+ : an extension of the Calculus of Constructions with fixpoints}}, - year = {1992} -} - -@InProceedings{Augustsson85, - author = {L. Augustsson}, - title = {{Compiling Pattern Matching}}, - booktitle = {Conference Functional Programming and -Computer Architecture}, - year = {1985} -} - -@Article{BaCo85, - author = {J.L. Bates and R.L. Constable}, - journal = {ACM transactions on Programming Languages and Systems}, - title = {Proofs as {Programs}}, - volume = {7}, - year = {1985} -} - @Book{Bar81, author = {H.P. Barendregt}, publisher = {North-Holland}, @@ -51,55 +10,6 @@ Computer Architecture}, year = {1981} } -@TechReport{Bar91, - author = {H. Barendregt}, - institution = {Catholic University Nijmegen}, - note = {In Handbook of Logic in Computer Science, Vol II}, - number = {91-19}, - title = {Lambda {Calculi with Types}}, - year = {1991} -} - -@Article{BeKe92, - author = {G. Bellin and J. Ketonen}, - journal = {Theoretical Computer Science}, - pages = {115--142}, - title = {A decision procedure revisited : Notes on direct logic, linear logic and its implementation}, - volume = {95}, - year = {1992} -} - -@Book{Bee85, - author = {M.J. Beeson}, - publisher = SV, - title = {Foundations of Constructive Mathematics, Metamathematical Studies}, - year = {1985} -} - -@Book{Bis67, - author = {E. Bishop}, - publisher = {McGraw-Hill}, - title = {Foundations of Constructive Analysis}, - year = {1967} -} - -@Book{BoMo79, - author = {R.S. Boyer and J.S. Moore}, - key = {BoMo79}, - publisher = {Academic Press}, - series = {ACM Monograph}, - title = {A computational logic}, - year = {1979} -} - -@MastersThesis{Bou92, - author = {S. Boutin}, - month = sep, - school = {{Universit\'e Paris 7}}, - title = {Certification d'un compilateur {ML en Coq}}, - year = {1992} -} - @InProceedings{Bou97, title = {Using reflection to build efficient and certified decision procedure s}, @@ -112,15 +22,6 @@ s}, year = {1997} } -@PhDThesis{Bou97These, - author = {S. Boutin}, - title = {R\'eflexions sur les quotients}, - school = {Paris 7}, - year = 1997, - type = {th\`ese d'Universit\'e}, - month = apr -} - @Article{Bru72, author = {N.J. de Bruijn}, journal = {Indag. Math.}, @@ -129,121 +30,6 @@ s}, year = {1972} } - -@InCollection{Bru80, - author = {N.J. de Bruijn}, - booktitle = {to H.B. Curry : Essays on Combinatory Logic, Lambda Calculus and Formalism.}, - editor = {J.P. Seldin and J.R. Hindley}, - publisher = {Academic Press}, - title = {A survey of the project {Automath}}, - year = {1980} -} - -@TechReport{COQ93, - author = {G. Dowek and A. Felty and H. Herbelin and G. Huet and C. Murthy and C. Parent and C. Paulin-Mohring and B. Werner}, - institution = {INRIA}, - month = may, - number = {154}, - title = {{The Coq Proof Assistant User's Guide Version 5.8}}, - year = {1993} -} - -@TechReport{COQ02, - author = {The Coq Development Team}, - institution = {INRIA}, - month = Feb, - number = {255}, - title = {{The Coq Proof Assistant Reference Manual Version 7.2}}, - year = {2002} -} - -@TechReport{CPar93, - author = {C. Parent}, - institution = {Ecole {Normale} {Sup\'erieure} de {Lyon}}, - month = oct, - note = {Also in~\cite{Nijmegen93}}, - number = {93-29}, - title = {Developing certified programs in the system {Coq}- {The} {Program} tactic}, - year = {1993} -} - -@PhDThesis{CPar95, - author = {C. Parent}, - school = {Ecole {Normale} {Sup\'erieure} de {Lyon}}, - title = {{Synth\`ese de preuves de programmes dans le Calcul des Constructions Inductives}}, - year = {1995} -} - -@Book{Caml, - author = {P. Weis and X. Leroy}, - publisher = {InterEditions}, - title = {Le langage Caml}, - year = {1993} -} - -@InProceedings{ChiPotSimp03, - author = {Laurent Chicli and Lo\"{\i}c Pottier and Carlos Simpson}, - title = {Mathematical Quotients and Quotient Types in Coq}, - booktitle = {TYPES}, - crossref = {DBLP:conf/types/2002}, - year = {2002} -} - -@TechReport{CoC89, - author = {Projet Formel}, - institution = {INRIA}, - number = {110}, - title = {{The Calculus of Constructions. Documentation and user's guide, Version 4.10}}, - year = {1989} -} - -@InProceedings{CoHu85a, - author = {Th. Coquand and G. Huet}, - address = {Linz}, - booktitle = {EUROCAL'85}, - publisher = SV, - series = LNCS, - title = {{Constructions : A Higher Order Proof System for Mechanizing Mathematics}}, - volume = {203}, - year = {1985} -} - -@InProceedings{CoHu85b, - author = {Th. Coquand and G. Huet}, - booktitle = {Logic Colloquium'85}, - editor = {The Paris Logic Group}, - publisher = {North-Holland}, - title = {{Concepts Math\'ematiques et Informatiques formalis\'es dans le Calcul des Constructions}}, - year = {1987} -} - -@Article{CoHu86, - author = {Th. Coquand and G. Huet}, - journal = {Information and Computation}, - number = {2/3}, - title = {The {Calculus of Constructions}}, - volume = {76}, - year = {1988} -} - -@InProceedings{CoPa89, - author = {Th. Coquand and C. Paulin-Mohring}, - booktitle = {Proceedings of Colog'88}, - editor = {P. Martin-L\"of and G. Mints}, - publisher = SV, - series = LNCS, - title = {Inductively defined types}, - volume = {417}, - year = {1990} -} - -@Book{Con86, - author = {R.L. {Constable et al.}}, - publisher = {Prentice-Hall}, - title = {{Implementing Mathematics with the Nuprl Proof Development System}}, - year = {1986} -} - @PhDThesis{Coq85, author = {Th. Coquand}, month = jan, @@ -261,24 +47,6 @@ s}, year = {1986} } -@InProceedings{Coq90, - author = {Th. Coquand}, - booktitle = {Logic and Computer Science}, - editor = {P. Oddifredi}, - note = {INRIA Research Report 1088, also in~\cite{CoC89}}, - publisher = {Academic Press}, - title = {{Metamathematical Investigations of a Calculus of Constructions}}, - year = {1990} -} - -@InProceedings{Coq91, - author = {Th. Coquand}, - booktitle = {Proceedings 9th Int. Congress of Logic, Methodology and Philosophy of Science}, - title = {{A New Paradox in Type Theory}}, - month = {August}, - year = {1991} -} - @InProceedings{Coq92, author = {Th. Coquand}, title = {{Pattern Matching with Dependent Types}}, @@ -286,49 +54,18 @@ s}, booktitle = {Proceedings of the 1992 Workshop on Types for Proofs and Programs} } -@InProceedings{Coquand93, - author = {Th. Coquand}, - booktitle = {Types for Proofs and Programs}, - editor = {H. Barendregt and T. Nipokow}, - publisher = SV, - series = LNCS, - title = {{Infinite objects in Type Theory}}, - volume = {806}, - year = {1993}, - pages = {62-78} -} - -@inproceedings{Corbineau08types, - author = {P. Corbineau}, - title = {A Declarative Language for the Coq Proof Assistant}, - editor = {M. Miculan and I. Scagnetto and F. Honsell}, - booktitle = {TYPES '07, Cividale del Friuli, Revised Selected Papers}, - publisher = {Springer}, - series = LNCS, - volume = {4941}, - year = {2007}, - pages = {69-84}, - ee = {http://dx.doi.org/10.1007/978-3-540-68103-8_5}, -} - -@PhDThesis{Cor97, - author = {C. Cornes}, - month = nov, - school = {{Universit\'e Paris 7}}, - title = {Conception d'un langage de haut niveau de représentation de preuves}, - type = {Th\`ese de Doctorat}, - year = {1997} -} - -@MastersThesis{Cou94a, - author = {J. Courant}, - month = sep, - school = {DEA d'Informatique, ENS Lyon}, - title = {Explicitation de preuves par r\'ecurrence implicite}, - year = {1994} +@InProceedings{DBLP:conf/types/CornesT95, + author = {Cristina Cornes and + Delphine Terrasse}, + title = {Automating Inversion of Inductive Predicates in Coq}, + booktitle = {TYPES}, + year = {1995}, + pages = {85-104}, + crossref = {DBLP:conf/types/1995}, + bibsource = {DBLP, http://dblp.uni-trier.de} } -@book{Cur58, +@Book{Cur58, author = {Haskell B. Curry and Robert Feys and William Craig}, title = {Combinatory Logic}, volume = 1, @@ -337,17 +74,40 @@ s}, note = {{\S{9E}}}, } -@InProceedings{Del99, - author = {Delahaye, D.}, - title = {Information Retrieval in a Coq Proof Library using - Type Isomorphisms}, - booktitle = {Proceedings of TYPES '99, L\"okeberg}, - publisher = SV, - series = lncs, - year = {1999}, - url = - "\\{\sf ftp://ftp.inria.fr/INRIA/Projects/coq/David.Delahaye/papers/}"# - "{\sf TYPES99-SIsos.ps.gz}" +@Article{CSlessadhoc, + author = {Gonthier, Georges and Ziliani, Beta and Nanevski, Aleksandar and Dreyer, Derek}, + title = {How to Make Ad Hoc Proof Automation Less Ad Hoc}, + journal = {SIGPLAN Not.}, + issue_date = {September 2011}, + volume = {46}, + number = {9}, + month = sep, + year = {2011}, + issn = {0362-1340}, + pages = {163--175}, + numpages = {13}, + url = {http://doi.acm.org/10.1145/2034574.2034798}, + doi = {10.1145/2034574.2034798}, + acmid = {2034798}, + publisher = {ACM}, + address = {New York, NY, USA}, + keywords = {canonical structures, coq, custom proof automation, hoare type theory, interactive theorem proving, tactics, type classes}, +} + +@InProceedings{CSwcu, + hal_id = {hal-00816703}, + url = {http://hal.inria.fr/hal-00816703}, + title = {{Canonical Structures for the working Coq user}}, + author = {Mahboubi, Assia and Tassi, Enrico}, + booktitle = {{ITP 2013, 4th Conference on Interactive Theorem Proving}}, + publisher = {Springer}, + pages = {19-34}, + address = {Rennes, France}, + volume = {7998}, + editor = {Sandrine Blazy and Christine Paulin and David Pichardie }, + series = {LNCS }, + doi = {10.1007/978-3-642-39634-2\_5 }, + year = {2013}, } @InProceedings{Del00, @@ -361,99 +121,7 @@ s}, pages = {85--95}, month = {November}, year = {2000}, - url = - "{\sf ftp://ftp.inria.fr/INRIA/Projects/coq/David.Delahaye/papers/}"# - "{\sf LPAR2000-ltac.ps.gz}" -} - -@InProceedings{DelMay01, - author = {Delahaye, D. and Mayero, M.}, - title = {{\tt Field}: une proc\'edure de d\'ecision pour les nombres r\'eels en {\Coq}}, - booktitle = {Journ\'ees Francophones des Langages Applicatifs, Pontarlier}, - publisher = {INRIA}, - month = {Janvier}, - year = {2001}, - url = - "\\{\sf ftp://ftp.inria.fr/INRIA/Projects/coq/David.Delahaye/papers/}"# - "{\sf JFLA2000-Field.ps.gz}" -} - -@TechReport{Dow90, - author = {G. Dowek}, - institution = {INRIA}, - number = {1283}, - title = {Naming and Scoping in a Mathematical Vernacular}, - type = {Research Report}, - year = {1990} -} - -@Article{Dow91a, - author = {G. Dowek}, - journal = {Compte-Rendus de l'Acad\'emie des Sciences}, - note = {The undecidability of Third Order Pattern Matching in Calculi with Dependent Types or Type Constructors}, - number = {12}, - pages = {951--956}, - title = {L'Ind\'ecidabilit\'e du Filtrage du Troisi\`eme Ordre dans les Calculs avec Types D\'ependants ou Constructeurs de Types}, - volume = {I, 312}, - year = {1991} -} - -@InProceedings{Dow91b, - author = {G. Dowek}, - booktitle = {Proceedings of Mathematical Foundation of Computer Science}, - note = {Also INRIA Research Report}, - pages = {151--160}, - publisher = SV, - series = LNCS, - title = {A Second Order Pattern Matching Algorithm in the Cube of Typed $\lambda$-calculi}, - volume = {520}, - year = {1991} -} - -@PhDThesis{Dow91c, - author = {G. Dowek}, - month = dec, - school = {Universit\'e Paris 7}, - title = {D\'emonstration automatique dans le Calcul des Constructions}, - year = {1991} -} - -@Article{Dow92a, - author = {G. Dowek}, - title = {The Undecidability of Pattern Matching in Calculi where Primitive Recursive Functions are Representable}, - year = 1993, - journal = {Theoretical Computer Science}, - volume = 107, - number = 2, - pages = {349-356} -} - -@Article{Dow94a, - author = {G. Dowek}, - journal = {Annals of Pure and Applied Logic}, - volume = {69}, - pages = {135--155}, - title = {Third order matching is decidable}, - year = {1994} -} - -@InProceedings{Dow94b, - author = {G. Dowek}, - booktitle = {Proceedings of the second international conference on typed lambda calculus and applications}, - title = {Lambda-calculus, Combinators and the Comprehension Schema}, - year = {1995} -} - -@InProceedings{Dyb91, - author = {P. Dybjer}, - booktitle = {Logical Frameworks}, - editor = {G. Huet and G. Plotkin}, - pages = {59--79}, - publisher = {Cambridge University Press}, - title = {Inductive sets and families in {Martin-Löf's} - Type Theory and their set-theoretic semantics: An inversion principle for {Martin-L\"of's} type theory}, - volume = {14}, - year = {1991} + url = {http://www.lirmm.fr/\%7Edelahaye/papers/ltac\%20(LPAR\%2700).pdf} } @Article{Dyc92, @@ -466,75 +134,6 @@ s}, year = {1992} } -@MastersThesis{Fil94, - author = {J.-C. Filli\^atre}, - month = sep, - school = {DEA d'Informatique, ENS Lyon}, - title = {Une proc\'edure de d\'ecision pour le Calcul des Pr\'edicats Direct. Étude et impl\'ementation dans le syst\`eme {\Coq}}, - year = {1994} -} - -@TechReport{Filliatre95, - author = {J.-C. Filli\^atre}, - institution = {LIP-ENS-Lyon}, - title = {A decision procedure for Direct Predicate Calculus}, - type = {Research report}, - number = {96--25}, - year = {1995} -} - -@Article{Filliatre03jfp, - author = {J.-C. Filliâtre}, - title = {Verification of Non-Functional Programs - using Interpretations in Type Theory}, - journal = jfp, - volume = 13, - number = 4, - pages = {709--745}, - month = jul, - year = 2003, - note = {[English translation of \cite{Filliatre99}]}, - url = {http://www.lri.fr/~filliatr/ftp/publis/jphd.ps.gz}, - topics = {team, lri}, - type_publi = {irevcomlec} -} - -@PhDThesis{Filliatre99, - author = {J.-C. Filli\^atre}, - title = {Preuve de programmes imp\'eratifs en th\'eorie des types}, - type = {Thèse de Doctorat}, - school = {Universit\'e Paris-Sud}, - year = 1999, - month = {July}, - url = {\url{http://www.lri.fr/~filliatr/ftp/publis/these.ps.gz}} -} - -@Unpublished{Filliatre99c, - author = {J.-C. Filli\^atre}, - title = {{Formal Proof of a Program: Find}}, - month = {January}, - year = 2000, - note = {Submitted to \emph{Science of Computer Programming}}, - url = {\url{http://www.lri.fr/~filliatr/ftp/publis/find.ps.gz}} -} - -@InProceedings{FilliatreMagaud99, - author = {J.-C. Filli\^atre and N. Magaud}, - title = {Certification of sorting algorithms in the system {\Coq}}, - booktitle = {Theorem Proving in Higher Order Logics: - Emerging Trends}, - year = 1999, - url = {\url{http://www.lri.fr/~filliatr/ftp/publis/Filliatre-Magaud.ps.gz}} -} - -@Unpublished{Fle90, - author = {E. Fleury}, - month = jul, - note = {Rapport de Stage}, - title = {Implantation des algorithmes de {Floyd et de Dijkstra} dans le {Calcul des Constructions}}, - year = {1990} -} - @Book{Fourier, author = {Jean-Baptiste-Joseph Fourier}, publisher = {Gauthier-Villars}, @@ -554,13 +153,6 @@ s}, year = {1994} } -@PhDThesis{Gim96, - author = {E. Gim\'enez}, - title = {Un calcul des constructions infinies et son application \'a la v\'erification de syst\`emes communicants}, - school = {\'Ecole Normale Sup\'erieure de Lyon}, - year = {1996} -} - @TechReport{Gim98, author = {E. Gim\'enez}, title = {A Tutorial on Recursive Types in Coq}, @@ -591,21 +183,6 @@ s}, year = {1995} } -@InProceedings{Gir70, - author = {J.-Y. Girard}, - booktitle = {Proceedings of the 2nd Scandinavian Logic Symposium}, - publisher = {North-Holland}, - title = {Une extension de l'interpr\'etation de {G\"odel} \`a l'analyse, et son application \`a l'\'elimination des coupures dans l'analyse et la th\'eorie des types}, - year = {1970} -} - -@PhDThesis{Gir72, - author = {J.-Y. Girard}, - school = {Universit\'e Paris~7}, - title = {Interpr\'etation fonctionnelle et \'elimination des coupures de l'arithm\'etique d'ordre sup\'erieur}, - year = {1972} -} - @Book{Gir89, author = {J.-Y. Girard and Y. Lafont and P. Taylor}, publisher = {Cambridge University Press}, @@ -614,32 +191,6 @@ s}, year = {1989} } -@TechReport{Har95, - author = {John Harrison}, - title = {Metatheory and Reflection in Theorem Proving: A Survey and Critique}, - institution = {SRI International Cambridge Computer Science Research Centre,}, - year = 1995, - type = {Technical Report}, - number = {CRC-053}, - abstract = {http://www.cl.cam.ac.uk/users/jrh/papers.html} -} - -@MastersThesis{Hir94, - author = {D. Hirschkoff}, - month = sep, - school = {DEA IARFA, Ecole des Ponts et Chauss\'ees, Paris}, - title = {Écriture d'une tactique arithm\'etique pour le syst\`eme {\Coq}}, - year = {1994} -} - -@InProceedings{HofStr98, - author = {Martin Hofmann and Thomas Streicher}, - title = {The groupoid interpretation of type theory}, - booktitle = {Proceedings of the meeting Twenty-five years of constructive type theory}, - publisher = {Oxford University Press}, - year = {1998} -} - @InCollection{How80, author = {W.A. Howard}, booktitle = {to H.B. Curry : Essays on Combinatory Logic, Lambda Calculus and Formalism.}, @@ -650,149 +201,31 @@ s}, year = {1980} } -@InProceedings{Hue87tapsoft, - author = {G. Huet}, - title = {Programming of Future Generation Computers}, - booktitle = {Proceedings of TAPSOFT87}, - series = LNCS, - volume = 249, - pages = {276--286}, - year = 1987, - publisher = SV -} - -@InProceedings{Hue87, - author = {G. Huet}, - booktitle = {Programming of Future Generation Computers}, - editor = {K. Fuchi and M. Nivat}, - note = {Also in \cite{Hue87tapsoft}}, - publisher = {Elsevier Science}, - title = {Induction Principles Formalized in the {Calculus of Constructions}}, - year = {1988} -} - @InProceedings{Hue88, author = {G. Huet}, booktitle = {A perspective in Theoretical Computer Science. Commemorative Volume for Gift Siromoney}, editor = {R. Narasimhan}, - note = {Also in~\cite{CoC89}}, publisher = {World Scientific Publishing}, title = {{The Constructive Engine}}, year = {1989} } -@Unpublished{Hue88b, - author = {G. Huet}, - title = {Extending the Calculus of Constructions with Type:Type}, - year = 1988, - note = {Unpublished} -} - -@Book{Hue89, - editor = {G. Huet}, - publisher = {Addison-Wesley}, - series = {The UT Year of Programming Series}, - title = {Logical Foundations of Functional Programming}, - year = {1989} -} - -@InProceedings{Hue92, - author = {G. Huet}, - booktitle = {Proceedings of 12th FST/TCS Conference, New Delhi}, - pages = {229--240}, - publisher = SV, - series = LNCS, - title = {The Gallina Specification Language : A case study}, - volume = {652}, - year = {1992} -} - -@Article{Hue94, - author = {G. Huet}, - journal = {J. Functional Programming}, - pages = {371--394}, - publisher = {Cambridge University Press}, - title = {Residual theory in $\lambda$-calculus: a formal development}, - volume = {4,3}, - year = {1994} -} - -@InCollection{HuetLevy79, - author = {G. Huet and J.-J. L\'{e}vy}, - title = {Call by Need Computations in Non-Ambigous -Linear Term Rewriting Systems}, - note = {Also research report 359, INRIA, 1979}, - booktitle = {Computational Logic, Essays in Honor of -Alan Robinson}, - editor = {J.-L. Lassez and G. Plotkin}, - publisher = {The MIT press}, - year = {1991} -} - -@Article{KeWe84, - author = {J. Ketonen and R. Weyhrauch}, - journal = {Theoretical Computer Science}, - pages = {297--307}, - title = {A decidable fragment of {P}redicate {C}alculus}, - volume = {32}, - year = {1984} -} - -@Book{Kle52, - author = {S.C. Kleene}, - publisher = {North-Holland}, - series = {Bibliotheca Mathematica}, - title = {Introduction to Metamathematics}, - year = {1952} -} - -@Book{Kri90, - author = {J.-L. Krivine}, - publisher = {Masson}, - series = {Etudes et recherche en informatique}, - title = {Lambda-calcul {types et mod\`eles}}, - year = {1990} -} - -@Book{LE92, - editor = {G. Huet and G. Plotkin}, - publisher = {Cambridge University Press}, - title = {Logical Environments}, - year = {1992} -} - -@Book{LF91, - editor = {G. Huet and G. Plotkin}, - publisher = {Cambridge University Press}, - title = {Logical Frameworks}, - year = {1991} -} - -@Article{Laville91, - author = {A. Laville}, - title = {Comparison of Priority Rules in Pattern -Matching and Term Rewriting}, - journal = {Journal of Symbolic Computation}, - volume = {11}, - pages = {321--347}, - year = {1991} -} - -@InProceedings{LePa94, - author = {F. Leclerc and C. Paulin-Mohring}, - booktitle = {{Types for Proofs and Programs, Types' 93}}, - editor = {H. Barendregt and T. Nipkow}, - publisher = SV, - series = {LNCS}, - title = {{Programming with Streams in Coq. A case study : The Sieve of Eratosthenes}}, - volume = {806}, - year = {1994} +@Article{LeeWerner11, + author = {Gyesik Lee and + Benjamin Werner}, + title = {Proof-irrelevant model of {CC} with predicative induction + and judgmental equality}, + journal = {Logical Methods in Computer Science}, + volume = {7}, + number = {4}, + year = {2011}, + ee = {http://dx.doi.org/10.2168/LMCS-7(4:5)2011}, + bibsource = {DBLP, http://dblp.uni-trier.de} } @TechReport{Leroy90, author = {X. Leroy}, - title = {The {ZINC} experiment: an economical implementation -of the {ML} language}, + title = {The {ZINC} experiment: an economical implementation of the {ML} language}, institution = {INRIA}, number = {117}, year = {1990} @@ -807,106 +240,23 @@ of the {ML} language}, url = {draft at \url{http://www.irif.fr/~letouzey/download/extraction2002.pdf}} } -@PhDThesis{Luo90, - author = {Z. Luo}, - title = {An Extended Calculus of Constructions}, - school = {University of Edinburgh}, - year = {1990} -} - -@inproceedings{Luttik97specificationof, - Author = {Sebastiaan P. Luttik and Eelco Visser}, - Booktitle = {2nd International Workshop on the Theory and Practice of Algebraic Specifications (ASF+SDF'97), Electronic Workshops in Computing}, - Publisher = {Springer-Verlag}, - Title = {Specification of Rewriting Strategies}, - Year = {1997}} - -@Book{MaL84, - author = {{P. Martin-L\"of}}, - publisher = {Bibliopolis}, - series = {Studies in Proof Theory}, - title = {Intuitionistic Type Theory}, - year = {1984} +@InProceedings{Luttik97specificationof, + author = {Sebastiaan P. Luttik and Eelco Visser}, + booktitle = {2nd International Workshop on the Theory and Practice of Algebraic Specifications (ASF+SDF'97), Electronic Workshops in Computing}, + publisher = {Springer-Verlag}, + title = {Specification of Rewriting Strategies}, + year = {1997} } -@Article{MaSi94, - author = {P. Manoury and M. Simonot}, - title = {Automatizing Termination Proofs of Recursively Defined Functions.}, - journal = {TCS}, - volume = {135}, - number = {2}, - year = {1994}, - pages = {319-343}, -} - -@InProceedings{Miquel00, - author = {A. Miquel}, - title = {A Model for Impredicative Type Systems with Universes, -Intersection Types and Subtyping}, - booktitle = {{Proceedings of the 15th Annual IEEE Symposium on Logic in Computer Science (LICS'00)}}, - publisher = {IEEE Computer Society Press}, - year = {2000} -} - -@PhDThesis{Miquel01a, - author = {A. Miquel}, - title = {Le Calcul des Constructions implicite: syntaxe et s\'emantique}, - month = {dec}, - school = {{Universit\'e Paris 7}}, - year = {2001} -} - -@InProceedings{Miquel01b, - author = {A. Miquel}, - title = {The Implicit Calculus of Constructions: Extending Pure Type Systems with an Intersection Type Binder and Subtyping}, - booktitle = {{Proceedings of the fifth International Conference on Typed Lambda Calculi and Applications (TLCA01), Krakow, Poland}}, - publisher = SV, - series = {LNCS}, - number = 2044, - year = {2001} -} - -@InProceedings{MiWer02, - author = {A. Miquel and B. Werner}, - title = {The Not So Simple Proof-Irrelevant Model of CC}, - booktitle = {TYPES}, - year = {2002}, - pages = {240-258}, - ee = {http://link.springer.de/link/service/series/0558/bibs/2646/26460240.htm}, - crossref = {DBLP:conf/types/2002}, - bibsource = {DBLP, http://dblp.uni-trier.de} -} - -@proceedings{DBLP:conf/types/2002, - editor = {H. Geuvers and F. Wiedijk}, - title = {Types for Proofs and Programs, Second International Workshop, - TYPES 2002, Berg en Dal, The Netherlands, April 24-28, 2002, - Selected Papers}, - booktitle = {TYPES}, - publisher = SV, - series = LNCS, - volume = {2646}, - year = {2003}, - isbn = {3-540-14031-X}, - bibsource = {DBLP, http://dblp.uni-trier.de} -} - -@InProceedings{Moh89a, - author = {C. Paulin-Mohring}, - address = {Austin}, - booktitle = {Sixteenth Annual ACM Symposium on Principles of Programming Languages}, - month = jan, - publisher = {ACM}, - title = {Extracting ${F}_{\omega}$'s programs from proofs in the {Calculus of Constructions}}, - year = {1989} -} - -@PhDThesis{Moh89b, - author = {C. Paulin-Mohring}, - month = jan, - school = {{Universit\'e Paris 7}}, - title = {Extraction de programmes dans le {Calcul des Constructions}}, - year = {1989} +@InProceedings{DBLP:conf/types/McBride00, + author = {Conor McBride}, + title = {Elimination with a Motive}, + booktitle = {TYPES}, + year = {2000}, + pages = {197-216}, + ee = {http://link.springer.de/link/service/series/0558/bibs/2277/22770197.htm}, + crossref = {DBLP:conf/types/2000}, + bibsource = {DBLP, http://dblp.uni-trier.de} } @InProceedings{Moh93, @@ -921,14 +271,6 @@ Intersection Types and Subtyping}, year = {1993} } -@Book{Moh97, - author = {C. Paulin-Mohring}, - month = jan, - publisher = {{ENS Lyon}}, - title = {{Le syst\`eme Coq. \mbox{Th\`ese d'habilitation}}}, - year = {1997} -} - @MastersThesis{Mun94, author = {C. Muñoz}, month = sep, @@ -937,73 +279,6 @@ Intersection Types and Subtyping}, year = {1994} } -@PhDThesis{Mun97d, - author = {C. Mu{\~{n}}oz}, - title = {Un calcul de substitutions pour la repr\'esentation - de preuves partielles en th\'eorie de types}, - school = {Universit\'e Paris 7}, - year = {1997}, - note = {Version en anglais disponible comme rapport de - recherche INRIA RR-3309}, - type = {Th\`ese de Doctorat} -} - -@Book{NoPS90, - author = {B. {Nordstr\"om} and K. Peterson and J. Smith}, - booktitle = {Information Processing 83}, - publisher = {Oxford Science Publications}, - series = {International Series of Monographs on Computer Science}, - title = {Programming in {Martin-L\"of's} Type Theory}, - year = {1990} -} - -@Article{Nor88, - author = {B. {Nordstr\"om}}, - journal = {BIT}, - title = {Terminating General Recursion}, - volume = {28}, - year = {1988} -} - -@Book{Odi90, - editor = {P. Odifreddi}, - publisher = {Academic Press}, - title = {Logic and Computer Science}, - year = {1990} -} - -@InProceedings{PaMS92, - author = {M. Parigot and P. Manoury and M. Simonot}, - address = {St. Petersburg, Russia}, - booktitle = {Logic Programming and automated reasoning}, - editor = {A. Voronkov}, - month = jul, - number = {624}, - publisher = SV, - series = {LNCS}, - title = {{ProPre : A Programming language with proofs}}, - year = {1992} -} - -@Article{PaWe92, - author = {C. Paulin-Mohring and B. Werner}, - journal = {Journal of Symbolic Computation}, - pages = {607--640}, - title = {{Synthesis of ML programs in the system Coq}}, - volume = {15}, - year = {1993} -} - -@Article{Par92, - author = {M. Parigot}, - journal = {Theoretical Computer Science}, - number = {2}, - pages = {335--356}, - title = {{Recursive Programming with Proofs}}, - volume = {94}, - year = {1992} -} - @InProceedings{Parent95b, author = {C. Parent}, booktitle = {{Mathematics of Program Construction'95}}, @@ -1015,14 +290,16 @@ the Calculus of Inductive Constructions}}, year = {1995} } -@InProceedings{Prasad93, - author = {K.V. Prasad}, - booktitle = {{Proceedings of CONCUR'93}}, - publisher = SV, - series = {LNCS}, - title = {{Programming with broadcasts}}, - volume = {715}, - year = {1993} +@Misc{Pcoq, + author = {Lemme Team}, + title = {Pcoq a graphical user-interface for {Coq}}, + note = {\url{http://www-sop.inria.fr/lemme/pcoq/}} +} + +@Misc{ProofGeneral, + author = {David Aspinall}, + title = {Proof General}, + note = {\url{https://proofgeneral.github.io/}} } @Book{RC95, @@ -1035,15 +312,6 @@ the Calculus of Inductive Constructions}}, note = {ISBN-0-8176-3763-X} } -@TechReport{Rou92, - author = {J. Rouyer}, - institution = {INRIA}, - month = nov, - number = {1795}, - title = {{Développement de l'Algorithme d'Unification dans le Calcul des Constructions}}, - year = {1992} -} - @Article{Rushby98, title = {Subtypes for Specifications: Predicate Subtyping in {PVS}}, @@ -1056,115 +324,7 @@ the Calculus of Inductive Constructions}}, year = 1998 } -@TechReport{Saibi94, - author = {A. Sa\"{\i}bi}, - institution = {INRIA}, - month = dec, - number = {2345}, - title = {{Axiomatization of a lambda-calculus with explicit-substitutions in the Coq System}}, - year = {1994} -} - - -@MastersThesis{Ter92, - author = {D. Terrasse}, - month = sep, - school = {IARFA}, - title = {{Traduction de TYPOL en COQ. Application \`a Mini ML}}, - year = {1992} -} - -@TechReport{ThBeKa92, - author = {L. Th\'ery and Y. Bertot and G. Kahn}, - institution = {INRIA Sophia}, - month = may, - number = {1684}, - title = {Real theorem provers deserve real user-interfaces}, - type = {Research Report}, - year = {1992} -} - -@Book{TrDa89, - author = {A.S. Troelstra and D. van Dalen}, - publisher = {North-Holland}, - series = {Studies in Logic and the foundations of Mathematics, volumes 121 and 123}, - title = {Constructivism in Mathematics, an introduction}, - year = {1988} -} - -@PhDThesis{Wer94, - author = {B. Werner}, - school = {Universit\'e Paris 7}, - title = {Une th\'eorie des constructions inductives}, - type = {Th\`ese de Doctorat}, - year = {1994} -} - -@PhDThesis{Bar99, - author = {B. Barras}, - school = {Universit\'e Paris 7}, - title = {Auto-validation d'un système de preuves avec familles inductives}, - type = {Th\`ese de Doctorat}, - year = {1999} -} - -@Unpublished{ddr98, - author = {D. de Rauglaudre}, - title = {Camlp4 version 1.07.2}, - year = {1998}, - note = {In Camlp4 distribution} -} - -@Article{dowek93, - author = {G. Dowek}, - title = {{A Complete Proof Synthesis Method for the Cube of Type Systems}}, - journal = {Journal Logic Computation}, - volume = {3}, - number = {3}, - pages = {287--315}, - month = {June}, - year = {1993} -} - -@InProceedings{manoury94, - author = {P. Manoury}, - title = {{A User's Friendly Syntax to Define -Recursive Functions as Typed $\lambda-$Terms}}, - booktitle = {{Types for Proofs and Programs, TYPES'94}}, - series = {LNCS}, - volume = {996}, - month = jun, - year = {1994} -} - -@TechReport{maranget94, - author = {L. Maranget}, - institution = {INRIA}, - number = {2385}, - title = {{Two Techniques for Compiling Lazy Pattern Matching}}, - year = {1994} -} - -@InProceedings{puel-suarez90, - author = {L.Puel and A. Su\'arez}, - booktitle = {{Conference Lisp and Functional Programming}}, - series = {ACM}, - publisher = SV, - title = {{Compiling Pattern Matching by Term -Decomposition}}, - year = {1990} -} - -@MastersThesis{saidi94, - author = {H. Saidi}, - month = sep, - school = {DEA d'Informatique Fondamentale, Universit\'e Paris 7}, - title = {R\'esolution d'\'equations dans le syst\`eme T - de G\"odel}, - year = {1994} -} - -@inproceedings{sozeau06, +@InProceedings{sozeau06, author = {Matthieu Sozeau}, title = {Subset Coercions in {C}oq}, year = {2007}, @@ -1175,7 +335,7 @@ Decomposition}}, series = {LNCS} } -@inproceedings{sozeau08, +@InProceedings{sozeau08, Author = {Matthieu Sozeau and Nicolas Oury}, booktitle = {TPHOLs'08}, Pdf = {http://www.lri.fr/~sozeau/research/publications/drafts/classes.pdf}, @@ -1183,96 +343,7 @@ Decomposition}}, Year = {2008}, } -@Misc{streicher93semantical, - author = {T. Streicher}, - title = {Semantical Investigations into Intensional Type Theory}, - note = {Habilitationsschrift, LMU Munchen.}, - year = {1993} -} - -@Misc{Pcoq, - author = {Lemme Team}, - title = {Pcoq a graphical user-interface for {Coq}}, - note = {\url{http://www-sop.inria.fr/lemme/pcoq/}} -} - -@Misc{ProofGeneral, - author = {David Aspinall}, - title = {Proof General}, - note = {\url{https://proofgeneral.github.io/}} -} - -@Book{CoqArt, - title = {Interactive Theorem Proving and Program Development. - Coq'Art: The Calculus of Inductive Constructions}, - author = {Yves Bertot and Pierre Castéran}, - publisher = {Springer Verlag}, - series = {Texts in Theoretical Computer Science. An EATCS series}, - year = 2004 -} - -@InCollection{wadler87, - author = {P. Wadler}, - title = {Efficient Compilation of Pattern Matching}, - booktitle = {The Implementation of Functional Programming -Languages}, - editor = {S.L. Peyton Jones}, - publisher = {Prentice-Hall}, - year = {1987} -} - -@inproceedings{DBLP:conf/types/CornesT95, - author = {Cristina Cornes and - Delphine Terrasse}, - title = {Automating Inversion of Inductive Predicates in Coq}, - booktitle = {TYPES}, - year = {1995}, - pages = {85-104}, - crossref = {DBLP:conf/types/1995}, - bibsource = {DBLP, http://dblp.uni-trier.de} -} -@proceedings{DBLP:conf/types/1995, - editor = {Stefano Berardi and - Mario Coppo}, - title = {Types for Proofs and Programs, International Workshop TYPES'95, - Torino, Italy, June 5-8, 1995, Selected Papers}, - booktitle = {TYPES}, - publisher = {Springer}, - series = {Lecture Notes in Computer Science}, - volume = {1158}, - year = {1996}, - isbn = {3-540-61780-9}, - bibsource = {DBLP, http://dblp.uni-trier.de} -} - -@inproceedings{DBLP:conf/types/McBride00, - author = {Conor McBride}, - title = {Elimination with a Motive}, - booktitle = {TYPES}, - year = {2000}, - pages = {197-216}, - ee = {http://link.springer.de/link/service/series/0558/bibs/2277/22770197.htm}, - crossref = {DBLP:conf/types/2000}, - bibsource = {DBLP, http://dblp.uni-trier.de} -} - -@proceedings{DBLP:conf/types/2000, - editor = {Paul Callaghan and - Zhaohui Luo and - James McKinna and - Robert Pollack}, - title = {Types for Proofs and Programs, International Workshop, TYPES - 2000, Durham, UK, December 8-12, 2000, Selected Papers}, - booktitle = {TYPES}, - publisher = {Springer}, - series = {Lecture Notes in Computer Science}, - volume = {2277}, - year = {2002}, - isbn = {3-540-43287-6}, - bibsource = {DBLP, http://dblp.uni-trier.de} -} - -@INPROCEEDINGS{sugar, +@InProceedings{sugar, author = {Alessandro Giovini and Teo Mora and Gianfranco Niesi and Lorenzo Robbiano and Carlo Traverso}, title = {"One sugar cube, please" or Selection strategies in the Buchberger algorithm}, booktitle = { Proceedings of the ISSAC'91, ACM Press}, @@ -1281,38 +352,7 @@ Languages}, publisher = {} } -@article{LeeWerner11, - author = {Gyesik Lee and - Benjamin Werner}, - title = {Proof-irrelevant model of {CC} with predicative induction - and judgmental equality}, - journal = {Logical Methods in Computer Science}, - volume = {7}, - number = {4}, - year = {2011}, - ee = {http://dx.doi.org/10.2168/LMCS-7(4:5)2011}, - bibsource = {DBLP, http://dblp.uni-trier.de} -} - -@Comment{cross-references, must be at end} - -@Book{Bastad92, - editor = {B. Nordstr\"om and K. Petersson and G. Plotkin}, - publisher = {Available by ftp at site ftp.inria.fr}, - title = {Proceedings of the 1992 Workshop on Types for Proofs and Programs}, - year = {1992} -} - -@Book{Nijmegen93, - editor = {H. Barendregt and T. Nipkow}, - publisher = SV, - series = LNCS, - title = {Types for Proofs and Programs}, - volume = {806}, - year = {1994} -} - -@article{TheOmegaPaper, +@Article{TheOmegaPaper, author = "W. Pugh", title = "The Omega test: a fast and practical integer programming algorithm for dependence analysis", journal = "Communication of the ACM", @@ -1320,43 +360,15 @@ Languages}, year = "1992", } -@inproceedings{CSwcu, - hal_id = {hal-00816703}, - url = {http://hal.inria.fr/hal-00816703}, - title = {{Canonical Structures for the working Coq user}}, - author = {Mahboubi, Assia and Tassi, Enrico}, - booktitle = {{ITP 2013, 4th Conference on Interactive Theorem Proving}}, - publisher = {Springer}, - pages = {19-34}, - address = {Rennes, France}, - volume = {7998}, - editor = {Sandrine Blazy and Christine Paulin and David Pichardie }, - series = {LNCS }, - doi = {10.1007/978-3-642-39634-2\_5 }, - year = {2013}, -} - -@article{CSlessadhoc, - author = {Gonthier, Georges and Ziliani, Beta and Nanevski, Aleksandar and Dreyer, Derek}, - title = {How to Make Ad Hoc Proof Automation Less Ad Hoc}, - journal = {SIGPLAN Not.}, - issue_date = {September 2011}, - volume = {46}, - number = {9}, - month = sep, - year = {2011}, - issn = {0362-1340}, - pages = {163--175}, - numpages = {13}, - url = {http://doi.acm.org/10.1145/2034574.2034798}, - doi = {10.1145/2034574.2034798}, - acmid = {2034798}, - publisher = {ACM}, - address = {New York, NY, USA}, - keywords = {canonical structures, coq, custom proof automation, hoare type theory, interactive theorem proving, tactics, type classes}, +@PhDThesis{Wer94, + author = {B. Werner}, + school = {Universit\'e Paris 7}, + title = {Une th\'eorie des constructions inductives}, + type = {Th\`ese de Doctorat}, + year = {1994} } -@inproceedings{CompiledStrongReduction, +@InProceedings{CompiledStrongReduction, author = {Benjamin Gr{\'{e}}goire and Xavier Leroy}, editor = {Mitchell Wand and @@ -1375,7 +387,7 @@ Languages}, bibsource = {dblp computer science bibliography, http://dblp.org} } -@inproceedings{FullReduction, +@InProceedings{FullReduction, author = {Mathieu Boespflug and Maxime D{\'{e}}n{\`{e}}s and Benjamin Gr{\'{e}}goire}, diff --git a/doc/sphinx/conf.py b/doc/sphinx/conf.py index 23bc9a2e4a..f65400e88c 100755 --- a/doc/sphinx/conf.py +++ b/doc/sphinx/conf.py @@ -51,6 +51,10 @@ extensions = [ 'coqrst.coqdomain' ] +# Change this to "info" or "warning" to get notifications about undocumented Coq +# objects (objects with no contents). +report_undocumented_coq_objects = None + # Add any paths that contain templates here, relative to this directory. templates_path = ['_templates'] @@ -96,11 +100,13 @@ language = None # directories to ignore when looking for source files. # This patterns also effect to html_static_path and html_extra_path exclude_patterns = [ - '_build', - 'Thumbs.db', - '.DS_Store', - 'introduction.rst', - 'credits.rst' + '_build', + 'Thumbs.db', + '.DS_Store', + 'introduction.rst', + 'credits.rst', + 'README.rst', + 'README.template.rst' ] # The reST default role (used for this markup: `text`) to use for all diff --git a/doc/sphinx/credits.rst b/doc/sphinx/credits.rst index fac0d0a4f9..a756597986 100644 --- a/doc/sphinx/credits.rst +++ b/doc/sphinx/credits.rst @@ -1307,9 +1307,9 @@ features and deprecations, cleanups of the internals of the system along with a few new features. The main user visible changes are: - Kernel: fix a subject reduction failure due to allowing fixpoints - on non-recursive values, which allows to recover full parametricity - for CIC, by Matthieu Sozeau. Handling of evars in the VM (the kernel - still does not accept evars) by Pierre-Marie Pédrot. + on non-recursive values, by Matthieu Sozeau. + Handling of evars in the VM (the kernel still does not accept evars) + by Pierre-Marie Pédrot. - Notations: many improvements on recursive notations and support for destructuring patterns in the syntax of notations by Hugo Herbelin. @@ -1338,7 +1338,14 @@ with a few new features. The main user visible changes are: - Documentation: a large community effort resulted in the migration of the reference manual to the Sphinx documentation tool. The result - is this manual. + is this manual. The new documentation infrastructure (based on Sphinx) + is by Clément Pit-Claudel. The migration was coordinated by Maxime Dénès + and Paul Steckler, with some help of Théo Zimmermann during the + final integration phase. The 14 people who ported the manual are + Calvin Beck, Heiko Becker, Yves Bertot, Maxime Dénès, Richard Ford, + Pierre Letouzey, Assia Mahboubi, Clément Pit-Claudel, + Laurence Rideau, Matthieu Sozeau, Paul Steckler, Enrico Tassi, + Laurent Théry, Nikita Zyuzin. - Tools: experimental ``-mangle-names`` option to coqtop/coqc for linting proof scripts, by Jasper Hugunin. @@ -1366,17 +1373,16 @@ The OPAM repository for |Coq| packages has been maintained by Guillaume Melquiond, Matthieu Sozeau, Enrico Tassi with contributions from many users. A list of packages is available at https://coq.inria.fr/opam/www. -The 40 contributors for this version are Yves Bertot, Joachim -Breitner, Tej Chajed, Arthur Charguéraud, Jacques-Pascal Deplaix, Maxime -Dénès, Jim Fehrle, Yannick Forster, Gaëtan Gilbert, Jason Gross, Samuel -Gruetter, Thomas Hebb, Hugo Herbelin, Jasper Hugunin, Emilio Jesus -Gallego Arias, Ralf Jung, Johannes Kloos, Matej Košík, Robbert Krebbers, -Tony Beta Lambda, Vincent Laporte, Pierre Letouzey, Farzon Lotfi, -Cyprien Mangin, Guillaume Melquiond, Raphaël Monat, Carl Patenaude -Poulin, Pierre-Marie Pédrot, Matthew Ryan, Matt Quinn, Sigurd Schneider, -Bernhard Schommer, Matthieu Sozeau, Arnaud Spiwack, Paul Steckler, -Enrico Tassi, Anton Trunov, Martin Vassor, Vadim Zaliva and Théo -Zimmermann. +The 44 contributors for this version are Yves Bertot, Joachim Breitner, Tej +Chajed, Arthur Charguéraud, Jacques-Pascal Deplaix, Maxime Dénès, Jim Fehrle, +Julien Forest, Yannick Forster, Gaëtan Gilbert, Jason Gross, Samuel Gruetter, +Thomas Hebb, Hugo Herbelin, Jasper Hugunin, Emilio Jesus Gallego Arias, Ralf +Jung, Johannes Kloos, Matej Košík, Robbert Krebbers, Tony Beta Lambda, Vincent +Laporte, Peter LeFanu Lumsdaine, Pierre Letouzey, Farzon Lotfi, Cyprien Mangin, +Guillaume Melquiond, Raphaël Monat, Carl Patenaude Poulin, Pierre-Marie Pédrot, +Clément Pit-Claudel, Matthew Ryan, Matt Quinn, Sigurd Schneider, Bernhard +Schommer, Michael Soegtrop, Matthieu Sozeau, Arnaud Spiwack, Paul Steckler, +Enrico Tassi, Anton Trunov, Martin Vassor, Vadim Zaliva and Théo Zimmermann. Version 8.8 is the third release of |Coq| developed on a time-based development cycle. Its development spanned 6 months from the release of diff --git a/doc/sphinx/index.rst b/doc/sphinx/index.rst index e2824d7ca8..136f9088b1 100644 --- a/doc/sphinx/index.rst +++ b/doc/sphinx/index.rst @@ -3,9 +3,6 @@ .. include:: preamble.rst .. include:: replaces.rst -Introduction -=========================================== - .. include:: introduction.rst .. include:: credits.rst @@ -16,6 +13,7 @@ Table of contents .. toctree:: :caption: The language + language/gallina-specification-language language/gallina-extensions language/coq-library language/cic @@ -24,8 +22,10 @@ Table of contents .. toctree:: :caption: The proof engine + proof-engine/vernacular-commands proof-engine/proof-handling proof-engine/tactics + proof-engine/ltac proof-engine/detailed-tactic-examples proof-engine/ssreflect-proof-language @@ -39,6 +39,7 @@ Table of contents :caption: Practical tools practical-tools/coq-commands + practical-tools/utilities practical-tools/coqide .. toctree:: @@ -57,6 +58,7 @@ Table of contents addendum/generalized-rewriting addendum/parallel-proof-processing addendum/miscellaneous-extensions + addendum/universe-polymorphism .. toctree:: :caption: Reference diff --git a/doc/sphinx/introduction.rst b/doc/sphinx/introduction.rst index 514745c1bf..75ff72c4da 100644 --- a/doc/sphinx/introduction.rst +++ b/doc/sphinx/introduction.rst @@ -2,12 +2,11 @@ Introduction ------------------------ -This document is the Reference Manual of version of the |Coq| proof -assistant. A companion volume, the |Coq| Tutorial, is provided for the -beginners. It is advised to read the Tutorial first. A -book :cite:`CoqArt` on practical uses of the |Coq| system was -published in 2004 and is a good support for both the beginner and the -advanced user. +This document is the Reference Manual of the |Coq| proof assistant. +To start using Coq, it is advised to first read a tutorial. +Links to several tutorials can be found at +https://coq.inria.fr/documentation (see also +https://github.com/coq/coq/wiki#coq-tutorials). The |Coq| system is designed to develop mathematical proofs, and especially to write formal specifications, programs and to verify that @@ -60,7 +59,7 @@ continuous reading. However, it has some structure that is explained below. - The first part describes the specification language, |Gallina|. - Chapters :ref:`thegallinaspecificationlanguage` and :ref:`extensionsofgallina` describe the concrete + Chapters :ref:`gallinaspecificationlanguage` and :ref:`extensionsofgallina` describe the concrete syntax as well as the meaning of programs, theorems and proofs in the Calculus of Inductive Constructions. Chapter :ref:`thecoqlibrary` describes the standard library of |Coq|. Chapter :ref:`calculusofinductiveconstructions` is a mathematical description @@ -76,7 +75,7 @@ below. Chapter :ref:`proofhandling`. In Chapter :ref:`tactics`, all commands that realize one or more steps of the proof are presented: we call them *tactics*. The language to combine these tactics into complex proof - strategies is given in Chapter :ref:`thetacticlanguage`. Examples of tactics + strategies is given in Chapter :ref:`ltac`. Examples of tactics are described in Chapter :ref:`detailedexamplesoftactics`. - The third part describes how to extend the syntax of |Coq|. It diff --git a/doc/sphinx/language/cic.rst b/doc/sphinx/language/cic.rst index 7ed6524095..f6bab02673 100644 --- a/doc/sphinx/language/cic.rst +++ b/doc/sphinx/language/cic.rst @@ -97,7 +97,7 @@ ensure the existence of a mapping of the universes to the positive integers, the graph of constraints must remain acyclic. Typing expressions that violate the acyclicity of the graph of constraints results in a Universe inconsistency error (see also Section -:ref:`TODO-2.10`). +:ref:`printing-universes`). .. _Terms: @@ -373,19 +373,22 @@ following rules. -**Remark**: **Prod-Prop** and **Prod-Set** typing-rules make sense if we consider the -semantic difference between :math:`\Prop` and :math:`\Set`: +.. note:: + **Prod-Prop** and **Prod-Set** typing-rules make sense if we consider the + semantic difference between :math:`\Prop` and :math:`\Set`: -+ All values of a type that has a sort :math:`\Set` are extractable. -+ No values of a type that has a sort :math:`\Prop` are extractable. + + All values of a type that has a sort :math:`\Set` are extractable. + + No values of a type that has a sort :math:`\Prop` are extractable. -**Remark**: We may have :math:`\letin{x}{t:T}{u}` well-typed without having -:math:`((λ x:T.u) t)` well-typed (where :math:`T` is a type of -:math:`t`). This is because the value :math:`t` associated to -:math:`x` may be used in a conversion rule (see Section :ref:`Conversion-rules`). +.. note:: + We may have :math:`\letin{x}{t:T}{u}` well-typed without having + :math:`((λ x:T.u) t)` well-typed (where :math:`T` is a type of + :math:`t`). This is because the value :math:`t` associated to + :math:`x` may be used in a conversion rule + (see Section :ref:`Conversion-rules`). .. _Conversion-rules: @@ -398,9 +401,11 @@ can decide if two programs are *intentionally* equal (one says *convertible*). Convertibility is described in this section. -.. _β-reduction: +.. _beta-reduction: + +β-reduction +~~~~~~~~~~~ -**β-reduction.** We want to be able to identify some terms as we can identify the application of a function to a given argument with its result. For instance the identity function over a given type T can be written @@ -424,9 +429,11 @@ theoretically of great importance but we will not detail them here and refer the interested reader to :cite:`Coq85`. -.. _ι-reduction: +.. _iota-reduction: + +ι-reduction +~~~~~~~~~~~ -**ι-reduction.** A specific conversion rule is associated to the inductive objects in the global environment. We shall give later on (see Section :ref:`Well-formed-inductive-definitions`) the precise rules but it @@ -435,9 +442,11 @@ constructor behaves as expected. This reduction is called ι-reduction and is more precisely studied in :cite:`Moh93,Wer94`. -.. _δ-reduction: +.. _delta-reduction: + +δ-reduction +~~~~~~~~~~~ -**δ-reduction.** We may have variables defined in local contexts or constants defined in the global environment. It is legal to identify such a reference with its value, that is to expand (or unfold) it into its value. This @@ -458,9 +467,11 @@ reduction is called δ-reduction and shows as follows. E[Γ] ⊢ c~\triangleright_δ~t -.. _ζ-reduction: +.. _zeta-reduction: + +ζ-reduction +~~~~~~~~~~~ -**ζ-reduction.** |Coq| allows also to remove local definitions occurring in terms by replacing the defined variable by its value. The declaration being destroyed, this reduction differs from δ-reduction. It is called @@ -475,9 +486,11 @@ destroyed, this reduction differs from δ-reduction. It is called E[Γ] ⊢ \letin{x}{u}{t}~\triangleright_ζ~\subst{t}{x}{u} -.. _η-expansion: +.. _eta-expansion: + +η-expansion +~~~~~~~~~~~ -**η-expansion.** Another important concept is η-expansion. It is legal to identify any term :math:`t` of functional type :math:`∀ x:T, U` with its so-called η-expansion @@ -487,34 +500,38 @@ term :math:`t` of functional type :math:`∀ x:T, U` with its so-called η-expan for :math:`x` an arbitrary variable name fresh in :math:`t`. -**Remark**: We deliberately do not define η-reduction: +.. note:: -.. math:: - λ x:T. (t~x) \not\triangleright_η t + We deliberately do not define η-reduction: -This is because, in general, the type of :math:`t` need not to be convertible -to the type of :math:`λ x:T. (t~x)`. E.g., if we take :math:`f` such that: + .. math:: + λ x:T. (t~x) \not\triangleright_η t -.. math:: - f : ∀ x:\Type(2),\Type(1) + This is because, in general, the type of :math:`t` need not to be convertible + to the type of :math:`λ x:T. (t~x)`. E.g., if we take :math:`f` such that: + + .. math:: + f : ∀ x:\Type(2),\Type(1) -then + then -.. math:: - λ x:\Type(1),(f~x) : ∀ x:\Type(1),\Type(1) + .. math:: + λ x:\Type(1),(f~x) : ∀ x:\Type(1),\Type(1) -We could not allow + We could not allow -.. math:: - λ x:Type(1),(f x) \triangleright_η f + .. math:: + λ x:Type(1),(f x) \triangleright_η f -because the type of the reduced term :math:`∀ x:\Type(2),\Type(1)` would not be -convertible to the type of the original term :math:`∀ x:\Type(1),\Type(1).` + because the type of the reduced term :math:`∀ x:\Type(2),\Type(1)` would not be + convertible to the type of the original term :math:`∀ x:\Type(1),\Type(1).` + +.. _convertibility: -.. _Convertibility: +Convertibility +~~~~~~~~~~~~~~ -**Convertibility.** Let us write :math:`E[Γ] ⊢ t \triangleright u` for the contextual closure of the relation :math:`t` reduces to :math:`u` in the global environment :math:`E` and local context :math:`Γ` with one of the previous @@ -704,8 +721,6 @@ called the *context of parameters*. Furthermore, we must have that each :math:`T` in :math:`(t:T)∈Γ_I` can be written as: :math:`∀Γ_P,∀Γ_{\mathit{Arr}(t)}, S` where :math:`Γ_{\mathit{Arr}(t)}` is called the *Arity* of the inductive type t and :math:`S` is called the sort of the inductive type t (not to be confused with :math:`\Sort` which is the set of sorts). - - ** Examples** The declaration for parameterized lists is: .. math:: @@ -794,18 +809,18 @@ contains an inductive declaration. --------------------- E[Γ] ⊢ c : C -**Example.** -Provided that our environment :math:`E` contains inductive definitions we showed before, -these two inference rules above enable us to conclude that: +.. example:: + Provided that our environment :math:`E` contains inductive definitions we showed before, + these two inference rules above enable us to conclude that: -.. math:: - \begin{array}{l} + .. math:: + \begin{array}{l} E[Γ] ⊢ \even : \nat→\Prop\\ E[Γ] ⊢ \odd : \nat→\Prop\\ E[Γ] ⊢ \even\_O : \even~O\\ E[Γ] ⊢ \even\_S : \forall~n:\nat, \odd~n → \even~(S~n)\\ E[Γ] ⊢ \odd\_S : \forall~n:\nat, \even~n → \odd~(S~n) - \end{array} + \end{array} @@ -820,8 +835,9 @@ to inconsistent systems. We restrict ourselves to definitions which satisfy a syntactic criterion of positivity. Before giving the formal rules, we need a few definitions: +Arity of a given sort ++++++++++++++++++++++ -**Type is an Arity of Sort S.** A type :math:`T` is an *arity of sort s* if it converts to the sort s or to a product :math:`∀ x:T,U` with :math:`U` an arity of sort s. @@ -831,7 +847,8 @@ product :math:`∀ x:T,U` with :math:`U` an arity of sort s. :math:`\Prop`. -**Type is an Arity.** +Arity ++++++ A type :math:`T` is an *arity* if there is a :math:`s∈ \Sort` such that :math:`T` is an arity of sort s. @@ -841,32 +858,34 @@ sort s. :math:`A→ Set` and :math:`∀ A:\Prop,A→ \Prop` are arities. -**Type of Constructor of I.** +Type constructor +++++++++++++++++ We say that T is a *type of constructor of I* in one of the following two cases: - + :math:`T` is :math:`(I~t_1 … t_n )` + :math:`T` is :math:`∀ x:U,T'` where :math:`T'` is also a type of constructor of :math:`I` - - .. example:: :math:`\nat` and :math:`\nat→\nat` are types of constructor of :math:`\nat`. :math:`∀ A:Type,\List~A` and :math:`∀ A:Type,A→\List~A→\List~A` are types of constructor of :math:`\List`. -**Positivity Condition.** +.. _positivity: + +Positivity Condition +++++++++++++++++++++ + The type of constructor :math:`T` will be said to *satisfy the positivity condition* for a constant :math:`X` in the following cases: - + :math:`T=(X~t_1 … t_n )` and :math:`X` does not occur free in any :math:`t_i` + :math:`T=∀ x:U,V` and :math:`X` occurs only strictly positively in :math:`U` and the type :math:`V` satisfies the positivity condition for :math:`X`. - -**Occurs Strictly Positively.** +Strict positivity ++++++++++++++++++ + The constant :math:`X` *occurs strictly positively* in :math:`T` in the following cases: @@ -886,63 +905,51 @@ cases: any of the :math:`t_i`, and the (instantiated) types of constructor :math:`\subst{C_i}{p_j}{a_j}_{j=1… m}` of :math:`I` satisfy the nested positivity condition for :math:`X` -**Nested Positivity Condition.** +Nested Positivity ++++++++++++++++++ + The type of constructor :math:`T` of :math:`I` *satisfies the nested positivity condition* for a constant :math:`X` in the following cases: - + :math:`T=(I~b_1 … b_m~u_1 … u_p)`, :math:`I` is an inductive definition with :math:`m` parameters and :math:`X` does not occur in any :math:`u_i` + :math:`T=∀ x:U,V` and :math:`X` occurs only strictly positively in :math:`U` and the type :math:`V` satisfies the nested positivity condition for :math:`X` -For instance, if one considers the type - .. example:: - .. coqtop:: all + For instance, if one considers the following variant of a tree type + branching over the natural numbers: - Module TreeExample. - Inductive tree (A:Type) : Type := - | leaf : tree A - | node : A -> (nat -> tree A) -> tree A. + .. coqtop:: in + + Inductive nattree (A:Type) : Type := + | leaf : nattree A + | node : A -> (nat -> nattree A) -> nattree A. End TreeExample. -:: + Then every instantiated constructor of ``nattree A`` satisfies the nested positivity + condition for ``nattree``: - [TODO Note: This commentary does not seem to correspond to the - preceding example. Instead it is referring to the first example - in Inductive Definitions section. It seems we should either - delete the preceding example and refer the the example above of - type `list A`, or else we should rewrite the commentary below.] - - Then every instantiated constructor of list A satisfies the nested positivity - condition for list - │ - ├─ concerning type list A of constructor nil: - │ Type list A of constructor nil satisfies the positivity condition for list - │ because list does not appear in any (real) arguments of the type of that - | constructor (primarily because list does not have any (real) - | arguments) ... (bullet 1) - │ - ╰─ concerning type ∀ A → list A → list A of constructor cons: - Type ∀ A : Type, A → list A → list A of constructor cons - satisfies the positivity condition for list because: - │ - ├─ list occurs only strictly positively in Type ... (bullet 3) - │ - ├─ list occurs only strictly positively in A ... (bullet 3) - │ - ├─ list occurs only strictly positively in list A ... (bullet 4) - │ - ╰─ list satisfies the positivity condition for list A ... (bullet 1) + + Type ``nattree A`` of constructor ``leaf`` satisfies the positivity condition for + ``nattree`` because ``nattree`` does not appear in any (real) arguments of the + type of that constructor (primarily because ``nattree`` does not have any (real) + arguments) ... (bullet 1) + + + Type ``A → (nat → nattree A) → nattree A`` of constructor ``node`` satisfies the + positivity condition for ``nattree`` because: + - ``nattree`` occurs only strictly positively in ``A`` ... (bullet 3) + - ``nattree`` occurs only strictly positively in ``nat → nattree A`` ... (bullet 3 + 2) + - ``nattree`` satisfies the positivity condition for ``nattree A`` ... (bullet 1) .. _Correctness-rules: -**Correctness rules.** +Correctness rules ++++++++++++++++++ + We shall now describe the rules allowing the introduction of a new inductive definition. @@ -1009,7 +1016,9 @@ has type :math:`\Type(k)` with :math:`k<j` and :math:`k≤ i`. .. _Template-polymorphism: -**Template polymorphism.** +Template polymorphism ++++++++++++++++++++++ + Inductive types declared in Type are polymorphic over their arguments in Type. If :math:`A` is an arity of some sort and s is a sort, we write :math:`A_{/s}` for the arity obtained from :math:`A` by replacing its sort with s. @@ -1053,7 +1062,7 @@ provided that the following side conditions hold: we have :math:`(E[Γ_{I′} ;Γ_{P′}] ⊢ C_i : s_{q_i})_{i=1… n}` ; + the sorts :math:`s_i` are such that all eliminations, to :math:`\Prop`, :math:`\Set` and :math:`\Type(j)`, are allowed - (see Section Destructors_). + (see Section :ref:`Destructors`). @@ -1083,14 +1092,14 @@ The sorts :math:`s_j` are chosen canonically so that each :math:`s_j` is minimal respect to the hierarchy :math:`\Prop ⊂ \Set_p ⊂ \Type` where :math:`\Set_p` is predicative :math:`\Set`. More precisely, an empty or small singleton inductive definition (i.e. an inductive definition of which all inductive types are -singleton – see paragraph Destructors_) is set in :math:`\Prop`, a small non-singleton +singleton – see Section :ref:`Destructors`) is set in :math:`\Prop`, a small non-singleton inductive type is set in :math:`\Set` (even in case :math:`\Set` is impredicative – see Section The-Calculus-of-Inductive-Construction-with-impredicative-Set_), and otherwise in the Type hierarchy. Note that the side-condition about allowed elimination sorts in the rule **Ind-Family** is just to avoid to recompute the allowed elimination -sorts at each instance of a pattern-matching (see section Destructors_). As +sorts at each instance of a pattern-matching (see Section :ref:`Destructors`). As an example, let us consider the following definition: .. example:: @@ -1106,7 +1115,7 @@ in the Type hierarchy. Here, the parameter :math:`A` has this property, hence, if :g:`option` is applied to a type in :math:`\Set`, the result is in :math:`\Set`. Note that if :g:`option` is applied to a type in :math:`\Prop`, then, the result is not set in :math:`\Prop` but in :math:`\Set` still. This is because :g:`option` is not a singleton type -(see section Destructors_) and it would lose the elimination to :math:`\Set` and :math:`\Type` +(see Section :ref:`Destructors`) and it would lose the elimination to :math:`\Set` and :math:`\Type` if set in :math:`\Prop`. .. example:: @@ -1135,9 +1144,10 @@ eliminations schemes are allowed. Check (fun (A:Prop) (B:Set) => prod A B). Check (fun (A:Type) (B:Prop) => prod A B). -Remark: Template polymorphism used to be called “sort-polymorphism of -inductive types” before universe polymorphism (see Chapter :ref:`polymorphicuniverses`) was -introduced. +.. note:: + Template polymorphism used to be called “sort-polymorphism of + inductive types” before universe polymorphism + (see Chapter :ref:`polymorphicuniverses`) was introduced. .. _Destructors: @@ -1213,9 +1223,11 @@ Coquand in :cite:`Coq92`. One is the definition by pattern-matching. The second one is a definition by guarded fixpoints. -.. _The-match…with-end-construction: +.. _match-construction: + +The match ... with ... end construction ++++++++++++++++++++++++++++++++++++++++ -**The match…with …end construction** The basic idea of this operator is that we have an object :math:`m` in an inductive type :math:`I` and we want to prove a property which possibly depends on :math:`m`. For this, it is enough to prove the property for @@ -1272,7 +1284,7 @@ and :math:`I:A` and :math:`λ a x . P : B` then by :math:`[I:A|B]` we mean that :math:`λ a x . P` with :math:`m` in the above match-construct. -.. _Notations: +.. _cic_notations: **Notations.** The :math:`[I:A|B]` is defined as the smallest relation satisfying the following rules: We write :math:`[I|B]` for :math:`[I:A|B]` where :math:`A` is the type of :math:`I`. @@ -1473,20 +1485,20 @@ definition :math:`\ind{r}{Γ_I}{Γ_C}` with :math:`Γ_C = [c_1 :C_1 ;…;c_n :C_ -**Example.** -Below is a typing rule for the term shown in the previous example: +.. example:: + Below is a typing rule for the term shown in the previous example: -.. inference:: list example + .. inference:: list example - \begin{array}{l} - E[Γ] ⊢ t : (\List ~\nat) \\ - E[Γ] ⊢ P : B \\ - [(\List ~\nat)|B] \\ - E[Γ] ⊢ f_1 : {(\kw{nil} ~\nat)}^P \\ - E[Γ] ⊢ f_2 : {(\kw{cons} ~\nat)}^P - \end{array} - ------------------------------------------------ - E[Γ] ⊢ \case(t,P,f_1 |f_2 ) : (P~t) + \begin{array}{l} + E[Γ] ⊢ t : (\List ~\nat) \\ + E[Γ] ⊢ P : B \\ + [(\List ~\nat)|B] \\ + E[Γ] ⊢ f_1 : {(\kw{nil} ~\nat)}^P \\ + E[Γ] ⊢ f_2 : {(\kw{cons} ~\nat)}^P + \end{array} + ------------------------------------------------ + E[Γ] ⊢ \case(t,P,f_1 |f_2 ) : (P~t) .. _Definition-of-ι-reduction: @@ -1619,9 +1631,8 @@ Given a variable :math:`y` of type an inductive definition in a declaration ones in which one of the :math:`I_l` occurs) are structurally smaller than y. -The following definitions are correct, we enter them using the ``Fixpoint`` -command as described in Section :ref:`TODO-1.3.4` and show the internal -representation. +The following definitions are correct, we enter them using the :cmd:`Fixpoint` +command and show the internal representation. .. example:: .. coqtop:: all @@ -1678,7 +1689,7 @@ possible: **Mutual induction** The principles of mutual induction can be automatically generated -using the Scheme command described in Section :ref:`TODO-13.1`. +using the Scheme command described in Section :ref:`proofschemes-induction-principles`. .. _Admissible-rules-for-global-environments: diff --git a/doc/sphinx/language/coq-library.rst b/doc/sphinx/language/coq-library.rst index 29053d6a57..afb49413dd 100644 --- a/doc/sphinx/language/coq-library.rst +++ b/doc/sphinx/language/coq-library.rst @@ -5,9 +5,6 @@ The |Coq| library ================= -:Source: https://coq.inria.fr/distrib/current/refman/stdlib.html -:Converted by: Pierre Letouzey - .. index:: single: Theories @@ -22,7 +19,7 @@ The |Coq| library is structured into two parts: developments of |Coq| axiomatizations about sets, lists, sorting, arithmetic, etc. This library comes with the system and its modules are directly accessible through the ``Require`` command (see - Section :ref:`TODO-6.5.1-Require`); + Section :ref:`compiled-files`); In addition, user-provided libraries or developments are provided by |Coq| users' community. These libraries and developments are available @@ -51,6 +48,7 @@ at the |Coq| root directory; this includes the modules ``Tactics``. Module ``Logic_Type`` also makes it in the initial state. +.. _init-notations: Notations ~~~~~~~~~ @@ -93,6 +91,8 @@ Notation Precedence Associativity ``_ ^ _`` 30 right ================ ============ =============== +.. _coq-library-logic: + Logic ~~~~~ @@ -200,6 +200,8 @@ The following abbreviations are allowed: The type annotation ``:A`` can be omitted when ``A`` can be synthesized by the system. +.. _coq-equality: + Equality ++++++++ @@ -524,7 +526,7 @@ provides a scope ``nat_scope`` gathering standard notations for common operations (``+``, ``*``) and a decimal notation for numbers, allowing for instance to write ``3`` for :g:`S (S (S O)))`. This also works on the left hand side of a ``match`` expression (see for example -section :ref:`TODO-refine-example`). This scope is opened by default. +section :tacn:`refine`). This scope is opened by default. .. example:: @@ -756,7 +758,7 @@ subdirectories: These directories belong to the initial load path of the system, and the modules they provide are compiled at installation time. So they are directly accessible with the command ``Require`` (see -Section :ref:`TODO-6.5.1-Require`). +Section :ref:`compiled-files`). The different modules of the |Coq| standard library are documented online at http://coq.inria.fr/stdlib. @@ -930,9 +932,8 @@ tactics (see Chapter :ref:`tactics`), there are also: Goal forall x y z:R, x * y * z <> 0. intros; split_Rmult. -These tactics has been written with the tactic language Ltac -described in Chapter :ref:`thetacticlanguage`. - +These tactics has been written with the tactic language |Ltac| +described in Chapter :ref:`ltac`. List library ~~~~~~~~~~~~ diff --git a/doc/sphinx/language/gallina-extensions.rst b/doc/sphinx/language/gallina-extensions.rst index 1d6c11b38d..6ea1c162f9 100644 --- a/doc/sphinx/language/gallina-extensions.rst +++ b/doc/sphinx/language/gallina-extensions.rst @@ -13,43 +13,42 @@ Extensions of |Gallina| Record types ---------------- -The ``Record`` construction is a macro allowing the definition of +The :cmd:`Record` construction is a macro allowing the definition of records as is done in many programming languages. Its syntax is -described in the grammar below. In fact, the ``Record`` macro is more general +described in the grammar below. In fact, the :cmd:`Record` macro is more general than the usual record types, since it allows also for “manifest” -expressions. In this sense, the ``Record`` construction allows defining +expressions. In this sense, the :cmd:`Record` construction allows defining “signatures”. .. _record_grammar: .. productionlist:: `sentence` - record : `record_keyword` ident [binders] [: sort] := [ident] { [`field` ; … ; `field`] }. + record : `record_keyword` `ident` [ `binders` ] [: `sort` ] := [ `ident` ] { [ `field` ; … ; `field` ] }. record_keyword : Record | Inductive | CoInductive - field : name [binders] : type [ where notation ] - : | name [binders] [: term] := term + field : `ident` [ `binders` ] : `type` [ where `notation` ] + : | `ident` [ `binders` ] [: `type` ] := `term` In the expression: -.. cmd:: Record @ident {* @param } {? : @sort} := {? @ident} { {*; @ident {* @binder } : @term } }. +.. cmd:: Record @ident @binders {? : @sort} := {? @ident} { {*; @ident @binders : @type } } -the first identifier `ident` is the name of the defined record and `sort` is its +the first identifier :token:`ident` is the name of the defined record and :token:`sort` is its type. The optional identifier following ``:=`` is the name of its constructor. If it is omitted, -the default name ``Build_``\ `ident`, where `ident` is the record name, is used. If `sort` is +the default name ``Build_``\ :token:`ident`, where :token:`ident` is the record name, is used. If :token:`sort` is omitted, the default sort is `\Type`. The identifiers inside the brackets are the names of -fields. For a given field `ident`, its type is :g:`forall binder …, term`. +fields. For a given field :token:`ident`, its type is :g:`forall binders, type`. Remark that the type of a particular identifier may depend on a previously-given identifier. Thus the -order of the fields is important. Finally, each `param` is a parameter of the record. +order of the fields is important. Finally, :token:`binders` are parameters of the record. More generally, a record may have explicitly defined (a.k.a. manifest) -fields. For instance, we might have:: - - Record ident param : sort := { ident₁ : type₁ ; ident₂ := term₂ ; ident₃ : type₃ }. - -in which case the correctness of |type_3| may rely on the instance |term_2| of |ident_2| and |term_2| in turn -may depend on |ident_1|. +fields. For instance, we might have: +:n:`Record @ident @binders : @sort := { @ident₁ : @type₁ ; @ident₂ := @term₂ ; @ident₃ : @type₃ }`. +in which case the correctness of :n:`@type₃` may rely on the instance :n:`@term₂` of :n:`@ident₂` and :n:`@term₂` may in turn depend on :n:`@ident₁`. .. example:: + The set of rational numbers may be defined as: + .. coqtop:: reset all Record Rat : Set := mkRat @@ -65,11 +64,10 @@ depends on both ``top`` and ``bottom``. Let us now see the work done by the ``Record`` macro. First the macro generates a variant type definition with just one constructor: +:n:`Variant @ident {? @binders } : @sort := @ident₀ {? @binders }`. -.. cmd:: Variant @ident {* @params} : @sort := @ident {* (@ident : @term_1)}. - -To build an object of type `ident`, one should provide the constructor -|ident_0| with the appropriate number of terms filling the fields of the record. +To build an object of type :n:`@ident`, one should provide the constructor +:n:`@ident₀` with the appropriate number of terms filling the fields of the record. .. example:: Let us define the rational :math:`1/2`: @@ -101,15 +99,15 @@ to be all present if the missing ones can be inferred or prompted for This syntax can be disabled globally for printing by -.. cmd:: Unset Printing Records. +.. cmd:: Unset Printing Records For a given type, one can override this using either -.. cmd:: Add Printing Record @ident. +.. cmd:: Add Printing Record @ident to get record syntax or -.. cmd:: Add Printing Constructor @ident. +.. cmd:: Add Printing Constructor @ident to get constructor syntax. @@ -144,7 +142,7 @@ available: It can be activated for printing with -.. cmd:: Set Printing Projections. +.. opt:: Printing Projections .. example:: @@ -169,7 +167,7 @@ and the syntax `term.(@qualid` |term_1| |term_n| `)` to `@qualid` |term_1| `…` In each case, `term` is the object projected and the other arguments are the parameters of the inductive type. -.. note::. Records defined with the ``Record`` keyword are not allowed to be +.. note:: Records defined with the ``Record`` keyword are not allowed to be recursive (references to the record's name in the type of its field raises an error). To define recursive records, one can use the ``Inductive`` and ``CoInductive`` keywords, resulting in an inductive or co-inductive record. @@ -179,9 +177,9 @@ other arguments are the parameters of the inductive type. .. note:: Induction schemes are automatically generated for inductive records. Automatic generation of induction schemes for non-recursive records defined with the ``Record`` keyword can be activated with the - ``Nonrecursive Elimination Schemes`` option (see :ref:`TODO-13.1.1-nonrecursive-elimination-schemes`). + ``Nonrecursive Elimination Schemes`` option (see :ref:`proofschemes-induction-principles`). -.. note::``Structure`` is a synonym of the keyword ``Record``. +.. note:: ``Structure`` is a synonym of the keyword ``Record``. .. warn:: @ident cannot be defined. @@ -189,9 +187,9 @@ other arguments are the parameters of the inductive type. This message is followed by an explanation of this impossibility. There may be three reasons: - #. The name `ident` already exists in the environment (see Section :ref:`TODO-1.3.1-axioms`). + #. The name `ident` already exists in the environment (see :cmd:`Axiom`). #. The body of `ident` uses an incorrect elimination for - `ident` (see Sections :ref:`TODO-1.3.4-fixpoint` and :ref:`TODO-4.5.3-case-expr`). + `ident` (see :cmd:`Fixpoint` and :ref:`Destructors`). #. The type of the projections `ident` depends on previous projections which themselves could not be defined. @@ -208,16 +206,18 @@ other arguments are the parameters of the inductive type. During the definition of the one-constructor inductive definition, all the errors of inductive definitions, as described in Section -:ref:`TODO-1.3.3-inductive-definitions`, may also occur. +:ref:`gallina-inductive-definitions`, may also occur. -**See also** Coercions and records in Section :ref:`TODO-18.9-coercions-and-records` of the chapter devoted to coercions. +**See also** Coercions and records in Section :ref:`coercions-classes-as-records` of the chapter devoted to coercions. .. _primitive_projections: Primitive Projections ~~~~~~~~~~~~~~~~~~~~~ -The option ``Set Primitive Projections`` turns on the use of primitive +.. opt:: Primitive Projections + +Turns on the use of primitive projections when defining subsequent records (even through the ``Inductive`` and ``CoInductive`` commands). Primitive projections extended the Calculus of Inductive Constructions with a new binary @@ -229,21 +229,27 @@ terms when manipulating parameterized records and typechecking time. On the user level, primitive projections can be used as a replacement for the usual defined ones, although there are a few notable differences. -The internally omitted parameters can be reconstructed at printing time -even though they are absent in the actual AST manipulated by the kernel. This -can be obtained by setting the ``Printing Primitive Projection Parameters`` -flag. Another compatibility printing can be activated thanks to the -``Printing Primitive Projection Compatibility`` option which governs the +.. opt:: Printing Primitive Projection Parameters + +This compatibility option reconstructs internally omitted parameters at +printing time (even though they are absent in the actual AST manipulated +by the kernel). + +.. opt:: Printing Primitive Projection Compatibility + +This compatibility option (on by default) governs the printing of pattern-matching over primitive records. Primitive Record Types ++++++++++++++++++++++ -When the ``Set Primitive Projections`` option is on, definitions of +When the :opt:`Primitive Projections` option is on, definitions of record types change meaning. When a type is declared with primitive projections, its :g:`match` construct is disabled (see :ref:`primitive_projections` though). To eliminate the (co-)inductive type, one must use its defined primitive projections. +.. The following paragraph is quite redundant with what is above + For compatibility, the parameters still appear to the user when printing terms even though they are absent in the actual AST manipulated by the kernel. This can be changed by unsetting the @@ -304,7 +310,7 @@ printed back as :g:`match` constructs. Variants and extensions of :g:`match` ------------------------------------- -.. _extended pattern-matching: +.. _mult-match: Multiple and nested pattern-matching ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -316,10 +322,11 @@ patterns are allowed, as in ML-like languages. The extension just acts as a macro that is expanded during parsing into a sequence of match on simple patterns. Especially, a construction defined using the extended match is generally printed -under its expanded form (see ``Set Printing Matching`` in :ref:`controlling-match-pp`). +under its expanded form (see :opt:`Printing Matching`). -See also: :ref:`extended pattern-matching`. +See also: :ref:`extendedpatternmatching`. +.. _if-then-else: Pattern-matching on boolean values: the if expression ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -366,6 +373,7 @@ we have the following equivalence Notice that the printing uses the :g:`if` syntax because `sumbool` is declared as such (see :ref:`controlling-match-pp`). +.. _irrefutable-patterns: Irrefutable patterns: the destructuring let variants ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -462,116 +470,63 @@ of :g:`match` expressions. Printing nested patterns +++++++++++++++++++++++++ +.. opt:: Printing Matching + The Calculus of Inductive Constructions knows pattern-matching only over simple patterns. It is however convenient to re-factorize nested pattern-matching into a single pattern-matching over a nested -pattern. |Coq|’s printer tries to do such limited re-factorization. - -.. cmd:: Set Printing Matching. +pattern. -This tells |Coq| to try to use nested patterns. This is the default -behavior. +When this option is on (default), |Coq|’s printer tries to do such +limited re-factorization. +Turning it off tells |Coq| to print only simple pattern-matching problems +in the same way as the |Coq| kernel handles them. -.. cmd:: Unset Printing Matching. - -This tells |Coq| to print only simple pattern-matching problems in the -same way as the |Coq| kernel handles them. - -.. cmd:: Test Printing Matching. - -This tells if the printing matching mode is on or off. The default is -on. Factorization of clauses with same right-hand side ++++++++++++++++++++++++++++++++++++++++++++++++++ +.. opt:: Printing Factorizable Match Patterns + When several patterns share the same right-hand side, it is additionally possible to share the clauses using disjunctive patterns. Assuming that the -printing matching mode is on, whether |Coq|'s printer shall try to do this kind -of factorization is governed by the following commands: - -.. cmd:: Set Printing Factorizable Match Patterns. - -This tells |Coq|'s printer to try to use disjunctive patterns. This is the -default behavior. - -.. cmd:: Unset Printing Factorizable Match Patterns. - -This tells |Coq|'s printer not to try to use disjunctive patterns. - -.. cmd:: Test Printing Factorizable Match Patterns. - -This tells if the factorization of clauses with same right-hand side is on or -off. +printing matching mode is on, this option (on by default) tells |Coq|'s +printer to try to do this kind of factorization. Use of a default clause +++++++++++++++++++++++ +.. opt:: Printing Allow Default Clause + When several patterns share the same right-hand side which do not depend on the arguments of the patterns, yet an extra factorization is possible: the disjunction of patterns can be replaced with a `_` default clause. Assuming that -the printing matching mode and the factorization mode are on, whether |Coq|'s -printer shall try to use a default clause is governed by the following commands: - -.. cmd:: Set Printing Allow Default Clause. - -This tells |Coq|'s printer to use a default clause when relevant. This is the -default behavior. - -.. cmd:: Unset Printing Allow Default Clause. - -This tells |Coq|'s printer not to use a default clause. - -.. cmd:: Test Printing Allow Default Clause. - -This tells if the use of a default clause is allowed. +the printing matching mode and the factorization mode are on, this option (on by +default) tells |Coq|'s printer to use a default clause when relevant. Printing of wildcard patterns ++++++++++++++++++++++++++++++ -Some variables in a pattern may not occur in the right-hand side of -the pattern-matching clause. There are options to control the display -of these variables. - -.. cmd:: Set Printing Wildcard. +.. opt:: Printing Wildcard -The variables having no occurrences in the right-hand side of the +Some variables in a pattern may not occur in the right-hand side of +the pattern-matching clause. When this option is on (default), the +variables having no occurrences in the right-hand side of the pattern-matching clause are just printed using the wildcard symbol “_”. -.. cmd:: Unset Printing Wildcard. - -The variables, even useless, are printed using their usual name. But -some non-dependent variables have no name. These ones are still -printed using a “_”. - -.. cmd:: Test Printing Wildcard. - -This tells if the wildcard printing mode is on or off. The default is -to print wildcard for useless variables. - Printing of the elimination predicate +++++++++++++++++++++++++++++++++++++ +.. opt:: Printing Synth + In most of the cases, the type of the result of a matched term is mechanically synthesizable. Especially, if the result type does not -depend of the matched term. - -.. cmd:: Set Printing Synth. - -The result type is not printed when |Coq| knows that it can re- +depend of the matched term. When this option is on (default), +the result type is not printed when |Coq| knows that it can re- synthesize it. -.. cmd:: Unset Printing Synth. - -This forces the result type to be always printed. - -.. cmd:: Test Printing Synth. - -This tells if the non-printing of synthesizable types is on or off. -The default is to not print synthesizable types. - Printing matching on irrefutable patterns ++++++++++++++++++++++++++++++++++++++++++ @@ -579,23 +534,23 @@ Printing matching on irrefutable patterns If an inductive type has just one constructor, pattern-matching can be written using the first destructuring let syntax. -.. cmd:: Add Printing Let @ident. +.. cmd:: Add Printing Let @ident This adds `ident` to the list of inductive types for which pattern-matching is written using a let expression. -.. cmd:: Remove Printing Let @ident. +.. cmd:: Remove Printing Let @ident This removes ident from this list. Note that removing an inductive type from this list has an impact only for pattern-matching written using :g:`match`. Pattern-matching explicitly written using a destructuring :g:`let` are not impacted. -.. cmd:: Test Printing Let for @ident. +.. cmd:: Test Printing Let for @ident This tells if `ident` belongs to the list. -.. cmd:: Print Table Printing Let. +.. cmd:: Print Table Printing Let This prints the list of inductive types for which pattern-matching is written using a let expression. @@ -611,20 +566,20 @@ Printing matching on booleans If an inductive type is isomorphic to the boolean type, pattern-matching can be written using ``if`` … ``then`` … ``else`` …: -.. cmd:: Add Printing If @ident. +.. cmd:: Add Printing If @ident This adds ident to the list of inductive types for which pattern-matching is written using an if expression. -.. cmd:: Remove Printing If @ident. +.. cmd:: Remove Printing If @ident This removes ident from this list. -.. cmd:: Test Printing If for @ident. +.. cmd:: Test Printing If for @ident This tells if ident belongs to the list. -.. cmd:: Print Table Printing If. +.. cmd:: Print Table Printing If This prints the list of inductive types for which pattern-matching is written using an if expression. @@ -662,12 +617,12 @@ Advanced recursive functions The following experimental command is available when the ``FunInd`` library has been loaded via ``Require Import FunInd``: -.. cmd:: Function @ident {* @binder} { @decrease_annot } : @type := @term. +.. cmd:: Function @ident {* @binder} { @decrease_annot } : @type := @term This command can be seen as a generalization of ``Fixpoint``. It is actually a wrapper for several ways of defining a function *and other useful related objects*, namely: an induction principle that reflects the recursive -structure of the function (see Section :ref:`TODO-8.5.5-functional-induction`) and its fixpoint equality. +structure of the function (see :tacn:`function induction`) and its fixpoint equality. The meaning of this declaration is to define a function ident, similarly to ``Fixpoint`. Like in ``Fixpoint``, the decreasing argument must be given (unless the function is not recursive), but it might not @@ -680,8 +635,8 @@ The ``Function`` construction also enjoys the ``with`` extension to define mutually recursive definitions. However, this feature does not work for non structurally recursive functions. -See the documentation of functional induction (:ref:`TODO-8.5.5-functional-induction`) -and ``Functional Scheme`` (:ref:`TODO-13.2-functional-scheme`) for how to use +See the documentation of functional induction (:tacn:`function induction`) +and ``Functional Scheme`` (:ref:`functional-scheme`) for how to use the induction principle to easily reason about the function. Remark: To obtain the right principle, it is better to put rigid @@ -729,11 +684,11 @@ presence of partial application of `wrong` in the body of For now, dependent cases are not treated for non structurally terminating functions. -.. exn:: The recursive argument must be specified -.. exn:: No argument name @ident -.. exn:: Cannot use mutual definition with well-founded recursion or measure +.. exn:: The recursive argument must be specified. +.. exn:: No argument name @ident. +.. exn:: Cannot use mutual definition with well-founded recursion or measure. -.. warn:: Cannot define graph for @ident +.. warn:: Cannot define graph for @ident. The generation of the graph relation (`R_ident`) used to compute the induction scheme of ident raised a typing error. Only `ident` is defined; the induction scheme @@ -743,16 +698,16 @@ terminating functions. which ``Function`` cannot deal with yet. - the definition is not a *pattern-matching tree* as explained above. -.. warn:: Cannot define principle(s) for @ident +.. warn:: Cannot define principle(s) for @ident. The generation of the graph relation (`R_ident`) succeeded but the induction principle could not be built. Only `ident` is defined. Please report. -.. warn:: Cannot build functional inversion principle +.. warn:: Cannot build functional inversion principle. `functional inversion` will not be available for the function. -See also: :ref:`TODO-13.2-generating-ind-principles` and ref:`TODO-8.5.5-functional-induction` +See also: :ref:`functional-scheme` and :tacn:`function induction` Depending on the ``{…}`` annotation, different definition mechanisms are used by ``Function``. A more precise description is given below. @@ -763,7 +718,7 @@ used by ``Function``. A more precise description is given below. the following are defined: + `ident_rect`, `ident_rec` and `ident_ind`, which reflect the pattern - matching structure of `term` (see the documentation of :ref:`TODO-1.3.3-Inductive`); + matching structure of `term` (see :cmd:`Inductive`); + The inductive `R_ident` corresponding to the graph of `ident` (silently); + `ident_complete` and `ident_correct` which are inversion information linking the function and its graph. @@ -812,21 +767,22 @@ used by ``Function``. A more precise description is given below. hand. Remark: Proof obligations are presented as several subgoals belonging to a Lemma `ident`\ :math:`_{\sf tcc}`. +.. _section-mechanism: Section mechanism ----------------- The sectioning mechanism can be used to to organize a proof in structured sections. Then local declarations become available (see -Section :ref:`TODO-1.3.2-Definitions`). +Section :ref:`gallina-definitions`). -.. cmd:: Section @ident. +.. cmd:: Section @ident This command is used to open a section named `ident`. -.. cmd:: End @ident. +.. cmd:: End @ident This command closes the section named `ident`. After closing of the section, the local declarations (variables and local definitions) get @@ -859,7 +815,7 @@ Section :ref:`TODO-1.3.2-Definitions`). Notice the difference between the value of `x’` and `x’’` inside section `s1` and outside. - .. exn:: This is not the last opened section + .. exn:: This is not the last opened section. **Remarks:** @@ -888,44 +844,44 @@ together, as well as a means of massive abstraction. In the syntax of module application, the ! prefix indicates that any `Inline` directive in the type of the functor arguments will be ignored -(see :ref:`named_module_type` below). +(see the ``Module Type`` command below). -.. cmd:: Module @ident. +.. cmd:: Module @ident This command is used to start an interactive module named `ident`. -.. cmdv:: Module @ident {* @module_binding}. +.. cmdv:: Module @ident {* @module_binding} Starts an interactive functor with parameters given by module_bindings. -.. cmdv:: Module @ident : @module_type. +.. cmdv:: Module @ident : @module_type Starts an interactive module specifying its module type. -.. cmdv:: Module @ident {* @module_binding} : @module_type. +.. cmdv:: Module @ident {* @module_binding} : @module_type Starts an interactive functor with parameters given by the list of `module binding`, and output module type `module_type`. -.. cmdv:: Module @ident <: {+<: @module_type }. +.. cmdv:: Module @ident <: {+<: @module_type } Starts an interactive module satisfying each `module_type`. - .. cmdv:: Module @ident {* @module_binding} <: {+<; @module_type }. + .. cmdv:: Module @ident {* @module_binding} <: {+<: @module_type }. Starts an interactive functor with parameters given by the list of `module_binding`. The output module type is verified against each `module_type`. -.. cmdv:: Module [ Import | Export ]. +.. cmdv:: Module [ Import | Export ] Behaves like ``Module``, but automatically imports or exports the module. Reserved commands inside an interactive module ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -.. cmd:: Include @module. +.. cmd:: Include @module Includes the content of module in the current interactive module. Here module can be a module expression or a module @@ -933,11 +889,11 @@ Reserved commands inside an interactive module expression then the system tries to instantiate module by the current interactive module. -.. cmd:: Include {+<+ @module}. +.. cmd:: Include {+<+ @module} is a shortcut for the commands ``Include`` `module` for each `module`. -.. cmd:: End @ident. +.. cmd:: End @ident This command closes the interactive module `ident`. If the module type was given the content of the module is matched against it and an error @@ -945,42 +901,40 @@ Reserved commands inside an interactive module functor) its components (constants, inductive types, submodules etc.) are now available through the dot notation. - .. exn:: No such label @ident + .. exn:: No such label @ident. - .. exn:: Signature components for label @ident do not match + .. exn:: Signature components for label @ident do not match. - .. exn:: This is not the last opened module + .. exn:: This is not the last opened module. -.. cmd:: Module @ident := @module_expression. +.. cmd:: Module @ident := @module_expression This command defines the module identifier `ident` to be equal to `module_expression`. - .. cmdv:: Module @ident {* @module_binding} := @module_expression. + .. cmdv:: Module @ident {* @module_binding} := @module_expression Defines a functor with parameters given by the list of `module_binding` and body `module_expression`. - .. cmdv:: Module @ident {* @module_binding} : @module_type := @module_expression. + .. cmdv:: Module @ident {* @module_binding} : @module_type := @module_expression Defines a functor with parameters given by the list of `module_binding` (possibly none), and output module type `module_type`, with body `module_expression`. - .. cmdv:: Module @ident {* @module_binding} <: {+<: @module_type} := @module_expression. + .. cmdv:: Module @ident {* @module_binding} <: {+<: @module_type} := @module_expression Defines a functor with parameters given by module_bindings (possibly none) with body `module_expression`. The body is checked against each |module_type_i|. - .. cmdv:: Module @ident {* @module_binding} := {+<+ @module_expression}. + .. cmdv:: Module @ident {* @module_binding} := {+<+ @module_expression} is equivalent to an interactive module where each `module_expression` is included. -.. _named_module_type: - -.. cmd:: Module Type @ident. +.. cmd:: Module Type @ident This command is used to start an interactive module type `ident`. - .. cmdv:: Module Type @ident {* @module_binding}. + .. cmdv:: Module Type @ident {* @module_binding} Starts an interactive functor type with parameters given by `module_bindings`. @@ -988,43 +942,44 @@ This command is used to start an interactive module type `ident`. Reserved commands inside an interactive module type: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -.. cmd:: Include @module. +.. cmd:: Include @module Same as ``Include`` inside a module. -.. cmd:: Include {+<+ @module}. +.. cmd:: Include {+<+ @module} is a shortcut for the command ``Include`` `module` for each `module`. -.. cmd:: @assumption_keyword Inline @assums. +.. cmd:: @assumption_keyword Inline @assums + :name: Inline The instance of this assumption will be automatically expanded at functor application, except when this functor application is prefixed by a ``!`` annotation. -.. cmd:: End @ident. +.. cmd:: End @ident This command closes the interactive module type `ident`. - .. exn:: This is not the last opened module type + .. exn:: This is not the last opened module type. -.. cmd:: Module Type @ident := @module_type. +.. cmd:: Module Type @ident := @module_type Defines a module type `ident` equal to `module_type`. - .. cmdv:: Module Type @ident {* @module_binding} := @module_type. + .. cmdv:: Module Type @ident {* @module_binding} := @module_type Defines a functor type `ident` specifying functors taking arguments `module_bindings` and returning `module_type`. - .. cmdv:: Module Type @ident {* @module_binding} := {+<+ @module_type }. + .. cmdv:: Module Type @ident {* @module_binding} := {+<+ @module_type } is equivalent to an interactive module type were each `module_type` is included. -.. cmd:: Declare Module @ident : @module_type. +.. cmd:: Declare Module @ident : @module_type Declares a module `ident` of type `module_type`. - .. cmdv:: Declare Module @ident {* @module_binding} : @module_type. + .. cmdv:: Declare Module @ident {* @module_binding} : @module_type Declares a functor with parameters given by the list of `module_binding` and output module type `module_type`. @@ -1188,107 +1143,107 @@ some of the fields and give one of its possible implementations: Notice that ``M`` is a correct body for the component ``M2`` since its ``T`` component is equal ``nat`` and hence ``M1.T`` as specified. -**Remarks:** +.. note:: -#. Modules and module types can be nested components of each other. -#. One can have sections inside a module or a module type, but not a - module or a module type inside a section. -#. Commands like ``Hint`` or ``Notation`` can also appear inside modules and - module types. Note that in case of a module definition like: + #. Modules and module types can be nested components of each other. + #. One can have sections inside a module or a module type, but not a + module or a module type inside a section. + #. Commands like ``Hint`` or ``Notation`` can also appear inside modules and + module types. Note that in case of a module definition like: -:: + :: - Module N : SIG := M. + Module N : SIG := M. -or:: + or:: - Module N : SIG. … End N. + Module N : SIG. … End N. -hints and the like valid for ``N`` are not those defined in ``M`` (or the module body) but the ones defined -in ``SIG``. + hints and the like valid for ``N`` are not those defined in ``M`` + (or the module body) but the ones defined in ``SIG``. .. _import_qualid: -.. cmd:: Import @qualid. +.. cmd:: Import @qualid If `qualid` denotes a valid basic module (i.e. its module type is a signature), makes its components available by their short names. -.. example:: + .. example:: - .. coqtop:: reset all + .. coqtop:: reset all - Module Mod. + Module Mod. - Definition T:=nat. + Definition T:=nat. - Check T. + Check T. - End Mod. + End Mod. - Check Mod.T. + Check Mod.T. - Fail Check T. + Fail Check T. - Import Mod. + Import Mod. - Check T. + Check T. -Some features defined in modules are activated only when a module is -imported. This is for instance the case of notations (see :ref:`TODO-12.1-Notations`). + Some features defined in modules are activated only when a module is + imported. This is for instance the case of notations (see :ref:`Notations`). -Declarations made with the Local flag are never imported by theImport -command. Such declarations are only accessible through their fully -qualified name. + Declarations made with the ``Local`` flag are never imported by the :cmd:`Import` + command. Such declarations are only accessible through their fully + qualified name. -.. example:: + .. example:: - .. coqtop:: all + .. coqtop:: all - Module A. + Module A. - Module B. + Module B. - Local Definition T := nat. + Local Definition T := nat. - End B. + End B. - End A. + End A. - Import A. + Import A. - Fail Check B.T. + Fail Check B.T. .. cmdv:: Export @qualid + :name: Export When the module containing the command Export qualid is imported, qualid is imported as well. - .. exn:: @qualid is not a module + .. exn:: @qualid is not a module. .. warn:: Trying to mask the absolute name @qualid! -.. cmd:: Print Module @ident. +.. cmd:: Print Module @ident - Prints the module type and (optionally) the body of the module `ident`. + Prints the module type and (optionally) the body of the module :n:`@ident`. -.. cmd:: Print Module Type @ident. +.. cmd:: Print Module Type @ident - Prints the module type corresponding to `ident`. + Prints the module type corresponding to :n:`@ident`. .. opt:: Short Module Printing - This option (off by default) disables the printing of the types of fields, - leaving only their names, for the commands ``Print Module`` and ``Print Module Type``. - -.. cmd:: Locate Module @qualid. - - Prints the full name of the module `qualid`. + This option (off by default) disables the printing of the types of fields, + leaving only their names, for the commands :cmd:`Print Module` and + :cmd:`Print Module Type`. Libraries and qualified names --------------------------------- +.. _names-of-libraries: + Names of libraries ~~~~~~~~~~~~~~~~~~ @@ -1296,15 +1251,16 @@ The theories developed in |Coq| are stored in *library files* which are hierarchically classified into *libraries* and *sublibraries*. To express this hierarchy, library names are represented by qualified identifiers qualid, i.e. as list of identifiers separated by dots (see -:ref:`TODO-1.2.3-identifiers`). For instance, the library file ``Mult`` of the standard +:ref:`gallina-identifiers`). For instance, the library file ``Mult`` of the standard |Coq| library ``Arith`` is named ``Coq.Arith.Mult``. The identifier that starts the name of a library is called a *library root*. All library files of the standard library of |Coq| have the reserved root |Coq| but library file names based on other roots can be obtained by using |Coq| commands -(coqc, coqtop, coqdep, …) options ``-Q`` or ``-R`` (see :ref:`TODO-14.3.3-command-line-options`). +(coqc, coqtop, coqdep, …) options ``-Q`` or ``-R`` (see :ref:`command-line-options`). Also, when an interactive |Coq| session starts, a library of root ``Top`` is -started, unless option ``-top`` or ``-notop`` is set (see :ref:`TODO-14.3.3-command-line-options`). +started, unless option ``-top`` or ``-notop`` is set (see :ref:`command-line-options`). +.. _qualified-names: Qualified names ~~~~~~~~~~~~~~~ @@ -1339,13 +1295,13 @@ names also applies to library file names. |Coq| maintains a table called the name table which maps partially qualified names of constructions to absolute names. This table is updated by the -commands ``Require`` (see :ref:`TODO-6.5.1-Require`), Import and Export (see :ref:`import_qualid`) and +commands :cmd:`Require`, :cmd:`Import` and :cmd:`Export` and also each time a new declaration is added to the context. An absolute name is called visible from a given short or partially qualified name when this latter name is enough to denote it. This means that the short or partially qualified name is mapped to the absolute name in |Coq| name table. Definitions flagged as Local are only accessible with -their fully qualified name (see :ref:`TODO-1.3.2-definitions`). +their fully qualified name (see :ref:`gallina-definitions`). It may happen that a visible name is hidden by the short name or a qualified name of another construction. In this case, the name that @@ -1367,16 +1323,15 @@ accessible, absolute names can never be hidden. Locate nat. -See also: Command Locate in :ref:`TODO-6.3.10-locate-qualid` and Locate Library in -:ref:`TODO-6.6.11-locate-library`. +See also: Commands :cmd:`Locate` and :cmd:`Locate Library`. +.. _libraries-and-filesystem: Libraries and filesystem ~~~~~~~~~~~~~~~~~~~~~~~~ -Please note that the questions described here have been subject to -redesign in |Coq| v8.5. Former versions of |Coq| use the same terminology -to describe slightly different things. +.. note:: The questions described here have been subject to redesign in |Coq| 8.5. + Former versions of |Coq| use the same terminology to describe slightly different things. Compiled files (``.vo`` and ``.vio``) store sub-libraries. In order to refer to them inside |Coq|, a translation from file-system names to |Coq| names @@ -1412,7 +1367,7 @@ translation and with an empty logical prefix. The command line option ``-R`` is a variant of ``-Q`` which has the strictly same behavior regarding loadpaths, but which also makes the corresponding ``.vo`` files available through their short names in a way -not unlike the ``Import`` command (see :ref:`import_qualid`). For instance, ``-R`` `path` ``Lib`` +not unlike the ``Import`` command (see :ref:`here <import_qualid>`). For instance, ``-R`` `path` ``Lib`` associates to the ``filepath/fOO/Bar/File.vo`` the logical name ``Lib.fOO.Bar.File``, but allows this file to be accessed through the short names ``fOO.Bar.File,Bar.File`` and ``File``. If several files with @@ -1420,7 +1375,7 @@ identical base name are present in different subdirectories of a recursive loadpath, which of these files is found first may be system- dependent and explicit qualification is recommended. The ``From`` argument of the ``Require`` command can be used to bypass the implicit shortening -by providing an absolute root to the required file (see :ref:`TODO-6.5.1-require-qualid`). +by providing an absolute root to the required file (see :ref:`compiled-files`). There also exists another independent loadpath mechanism attached to OCaml object files (``.cmo`` or ``.cmxs``) rather than |Coq| object @@ -1428,11 +1383,12 @@ files as described above. The OCaml loadpath is managed using the option ``-I`` `path` (in the OCaml world, there is neither a notion of logical name prefix nor a way to access files in subdirectories of path). See the command ``Declare`` ``ML`` ``Module`` in -:ref:`TODO-6.5-compiled-files` to understand the need of the OCaml loadpath. +:ref:`compiled-files` to understand the need of the OCaml loadpath. -See :ref:`TODO-14.3.3-command-line-options` for a more general view over the |Coq| command +See :ref:`command-line-options` for a more general view over the |Coq| command line options. +.. _ImplicitArguments: Implicit arguments ------------------ @@ -1477,7 +1433,9 @@ For instance, the first argument of in module ``List.v`` is strict because :g:`list` is an inductive type and :g:`A` will always be inferable from the type :g:`list A` of the third argument of -:g:`cons`. On the contrary, the second argument of a term of type +:g:`cons`. Also, the first argument of :g:`cons` is strict with respect to the second one, +since the first argument is exactly the type of the second argument. +On the contrary, the second argument of a term of type :: forall P:nat->Prop, forall n:nat, P n -> ex nat P @@ -1548,10 +1506,9 @@ inserted. In the second case, the function is considered to be implicitly applied to the implicit arguments it is waiting for: one says that the implicit argument is maximally inserted. -Each implicit argument can be declared to have to be inserted -maximally or non maximally. This can be governed argument per argument -by the command ``Implicit Arguments`` (see Section :ref:`declare-implicit-args`) or globally by the -command ``Set Maximal Implicit Insertion`` (see Section :ref:`controlling-insertion-implicit-args`). +Each implicit argument can be declared to have to be inserted maximally or non +maximally. This can be governed argument per argument by the command +:cmd:`Arguments (implicits)` or globally by the :opt:`Maximal Implicit Insertion` option. See also :ref:`displaying-implicit-args`. @@ -1564,6 +1521,7 @@ force the given argument to be guessed by replacing it by “_”. If possible, the correct argument will be automatically generated. .. exn:: Cannot infer a term for this placeholder. + :name: Cannot infer a term for this placeholder. (Casual use of implicit arguments) |Coq| was not able to deduce an instantiation of a “_”. @@ -1603,7 +1561,7 @@ absent in every situation but still be able to specify it if needed: The syntax is supported in all top-level definitions: -``Definition``, ``Fixpoint``, ``Lemma`` and so on. For (co-)inductive datatype +:cmd:`Definition`, :cmd:`Fixpoint`, :cmd:`Lemma` and so on. For (co-)inductive datatype declarations, the semantics are the following: an inductive parameter declared as an implicit argument need not be repeated in the inductive definition but will become implicit for the constructors of the @@ -1626,7 +1584,8 @@ Declaring Implicit Arguments To set implicit arguments *a posteriori*, one can use the command: -.. cmd:: Arguments @qualid {* @possibly_bracketed_ident }. +.. cmd:: Arguments @qualid {* @possibly_bracketed_ident } + :name: Arguments (implicits) where the list of `possibly_bracketed_ident` is a prefix of the list of arguments of `qualid` where the ones to be declared implicit are @@ -1639,7 +1598,7 @@ of `qualid`. Implicit arguments can be cleared with the following syntax: -.. cmd:: Arguments @qualid : clear implicits. +.. cmd:: Arguments @qualid : clear implicits .. cmdv:: Global Arguments @qualid {* @possibly_bracketed_ident } @@ -1648,13 +1607,13 @@ Implicit arguments can be cleared with the following syntax: implicit arguments known from inside the section to be the ones declared by the command. -.. cmdv:: Local Arguments @qualid {* @possibly_bracketed_ident }. +.. cmdv:: Local Arguments @qualid {* @possibly_bracketed_ident } When in a module, tell not to activate the implicit arguments ofqualid declared by this command to contexts that require the module. -.. cmdv:: {? Global | Local } Arguments @qualid {*, {+ @possibly_bracketed_ident } }. +.. cmdv:: {? Global | Local } Arguments @qualid {*, {+ @possibly_bracketed_ident } } For names of constants, inductive types, constructors, lemmas which can only be applied to a fixed number of @@ -1706,7 +1665,7 @@ Automatic declaration of implicit arguments |Coq| can also automatically detect what are the implicit arguments of a defined object. The command is just -.. cmd:: Arguments @qualid : default implicits. +.. cmd:: Arguments @qualid : default implicits The auto-detection is governed by options telling if strict, contextual, or reversible-pattern implicit arguments must be @@ -1780,14 +1739,10 @@ appear strictly in the body of the type, they are implicit. Mode for automatic declaration of implicit arguments ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -In case one wants to systematically declare implicit the arguments -detectable as such, one may switch to the automatic declaration of -implicit arguments mode by using the command: - -.. cmd:: Set Implicit Arguments. +.. opt:: Implicit Arguments -Conversely, one may unset the mode by using ``Unset Implicit Arguments``. -The mode is off by default. Auto-detection of implicit arguments is +This option (off by default) allows to systematically declare implicit +the arguments detectable as such. Auto-detection of implicit arguments is governed by options controlling whether strict and contextual implicit arguments have to be considered or not. @@ -1796,76 +1751,55 @@ arguments have to be considered or not. Controlling strict implicit arguments ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.. opt:: Strict Implicit + When the mode for automatic declaration of implicit arguments is on, the default is to automatically set implicit only the strict implicit arguments plus, for historical reasons, a small subset of the non-strict implicit arguments. To relax this constraint and to set -implicit all non strict implicit arguments by default, use the command: - -.. cmd:: Unset Strict Implicit. +implicit all non strict implicit arguments by default, you can turn this +option off. -Conversely, use the command ``Set Strict Implicit`` to restore the -original mode that declares implicit only the strict implicit -arguments plus a small subset of the non strict implicit arguments. +.. opt:: Strongly Strict Implicit -In the other way round, to capture exactly the strict implicit -arguments and no more than the strict implicit arguments, use the -command - -.. cmd:: Set Strongly Strict Implicit. - -Conversely, use the command ``Unset Strongly Strict Implicit`` to let the -option “Strict Implicit” decide what to do. - -Remark: In versions of |Coq| prior to version 8.0, the default was to -declare the strict implicit arguments as implicit. +Use this option (off by default) to capture exactly the strict implicit +arguments and no more than the strict implicit arguments. .. _controlling-contextual-implicit-args: Controlling contextual implicit arguments ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -By default, |Coq| does not automatically set implicit the contextual -implicit arguments. To tell |Coq| to infer also contextual implicit -argument, use command - -.. cmd:: Set Contextual Implicit. +.. opt:: Contextual Implicit -Conversely, use command ``Unset Contextual Implicit`` to unset the -contextual implicit mode. +By default, |Coq| does not automatically set implicit the contextual +implicit arguments. You can turn this option on to tell |Coq| to also +infer contextual implicit argument. .. _controlling-rev-pattern-implicit-args: Controlling reversible-pattern implicit arguments ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -By default, |Coq| does not automatically set implicit the reversible-pattern -implicit arguments. To tell |Coq| to infer also reversible- -pattern implicit argument, use command - -.. cmd:: Set Reversible Pattern Implicit. +.. opt:: Reversible Pattern Implicit -Conversely, use command ``Unset Reversible Pattern Implicit`` to unset the -reversible-pattern implicit mode. +By default, |Coq| does not automatically set implicit the reversible-pattern +implicit arguments. You can turn this option on to tell |Coq| to also infer +reversible-pattern implicit argument. .. _controlling-insertion-implicit-args: Controlling the insertion of implicit arguments not followed by explicit arguments ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -Implicit arguments can be declared to be automatically inserted when a -function is partially applied and the next argument of the function is -an implicit one. In case the implicit arguments are automatically -declared (with the command ``Set Implicit Arguments``), the command - -.. cmd:: Set Maximal Implicit Insertion. +.. opt:: Maximal Implicit Insertion -is used to tell to declare the implicit arguments with a maximal -insertion status. By default, automatically declared implicit -arguments are not declared to be insertable maximally. To restore the -default mode for maximal insertion, use the command +Assuming the implicit argument mode is on, this option (off by default) +declares implicit arguments to be automatically inserted when a +function is partially applied and the next argument of the function is +an implicit one. -.. cmd:: Unset Maximal Implicit Insertion. +.. _explicit-applications: Explicit applications ~~~~~~~~~~~~~~~~~~~~~ @@ -1904,7 +1838,7 @@ Renaming implicit arguments Implicit arguments names can be redefined using the following syntax: -.. cmd:: Arguments @qualid {* @name} : @rename. +.. cmd:: Arguments @qualid {* @name} : @rename With the assert flag, ``Arguments`` can be used to assert that a given object has the expected number of arguments and that these arguments @@ -1930,33 +1864,25 @@ Displaying what the implicit arguments are To display the implicit arguments associated to an object, and to know if each of them is to be used maximally or not, use the command -.. cmd:: Print Implicit @qualid. +.. cmd:: Print Implicit @qualid Explicit displaying of implicit arguments for pretty-printing ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -By default the basic pretty-printing rules hide the inferable implicit -arguments of an application. To force printing all implicit arguments, -use command - -.. cmd:: Set Printing Implicit. +.. opt:: Printing Implicit -Conversely, to restore the hiding of implicit arguments, use command +By default, the basic pretty-printing rules hide the inferable implicit +arguments of an application. Turn this option on to force printing all +implicit arguments. -.. cmd:: Unset Printing Implicit. +.. opt:: Printing Implicit Defensive -By default the basic pretty-printing rules display the implicit +By default, the basic pretty-printing rules display the implicit arguments that are not detected as strict implicit arguments. This “defensive” mode can quickly make the display cumbersome so this can -be deactivated by using the command - -.. cmd:: Unset Printing Implicit Defensive. +be deactivated by turning this option off. -Conversely, to force the display of non strict arguments, use command - -.. cmd:: Set Printing Implicit Defensive. - -See also: ``Set Printing All`` in :ref:`printing_constructions_full`. +See also: :opt:`Printing All`. Interaction with subtyping ~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -1981,17 +1907,14 @@ but succeeds in Deactivation of implicit arguments for parsing ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -Use of implicit arguments can be deactivated by issuing the command: +.. opt:: Parsing Explicit -.. cmd:: Set Parsing Explicit. +Turning this option on (it is off by default) deactivates the use of implicit arguments. In this case, all arguments of constants, inductive types, constructors, etc, including the arguments declared as implicit, have -to be given as if none arguments were implicit. By symmetry, this also -affects printing. To restore parsing and normal printing of implicit -arguments, use: - -.. cmd:: Unset Parsing Explicit. +to be given as if no arguments were implicit. By symmetry, this also +affects printing. Canonical structures ~~~~~~~~~~~~~~~~~~~~ @@ -2006,7 +1929,7 @@ Assume that `qualid` denotes an object ``(Build_struc`` |c_1| … |c_n| ``)`` in structure *struct* of which the fields are |x_1|, …, |x_n|. Assume that `qualid` is declared as a canonical structure using the command -.. cmd:: Canonical Structure @qualid. +.. cmd:: Canonical Structure @qualid Then, each time an equation of the form ``(``\ |x_i| ``_)`` |eq_beta_delta_iota_zeta| |c_i| has to be solved during the type-checking process, `qualid` is used as a solution. @@ -2047,11 +1970,11 @@ and ``B`` can be synthesized in the next statement. Remark: If a same field occurs in several canonical structure, then only the structure declared first as canonical is considered. -.. cmdv:: Canonical Structure @ident := @term : @type. +.. cmdv:: Canonical Structure @ident := @term : @type -.. cmdv:: Canonical Structure @ident := @term. +.. cmdv:: Canonical Structure @ident := @term -.. cmdv:: Canonical Structure @ident : @type := @term. +.. cmdv:: Canonical Structure @ident : @type := @term These are equivalent to a regular definition of `ident` followed by the declaration ``Canonical Structure`` `ident`. @@ -2079,7 +2002,7 @@ It is possible to bind variable names to a given type (e.g. in a development using arithmetic, it may be convenient to bind the names `n` or `m` to the type ``nat`` of natural numbers). The command for that is -.. cmd:: Implicit Types {+ @ident } : @type. +.. cmd:: Implicit Types {+ @ident } : @type The effect of the command is to automatically set the type of bound variables starting with `ident` (either `ident` itself or `ident` followed by @@ -2101,7 +2024,7 @@ case, this latter type is considered). Lemma cons_inj_bool : forall (m n:bool) l, n :: l = m :: l -> n = m. -.. cmdv:: Implicit Type @ident : @type. +.. cmdv:: Implicit Type @ident : @type This is useful for declaring the implicit type of a single variable. @@ -2140,7 +2063,7 @@ the ``Generalizable`` vernacular command to avoid unexpected generalizations when mistyping identifiers. There are several commands that specify which variables should be generalizable. -.. cmd:: Generalizable All Variables. +.. cmd:: Generalizable All Variables All variables are candidate for generalization if they appear free in the context under a @@ -2148,16 +2071,16 @@ that specify which variables should be generalizable. of typos. In such cases, the context will probably contain some unexpected generalized variable. -.. cmd:: Generalizable No Variables. +.. cmd:: Generalizable No Variables Disable implicit generalization entirely. This is the default behavior. -.. cmd:: Generalizable (Variable | Variables) {+ @ident }. +.. cmd:: Generalizable (Variable | Variables) {+ @ident } Allow generalization of the given identifiers only. Calling this command multiple times adds to the allowed identifiers. -.. cmd:: Global Generalizable. +.. cmd:: Global Generalizable Allows exporting the choice of generalizable variables. @@ -2177,6 +2100,7 @@ implicitly, as maximally-inserted arguments. In these binders, the binding name for the bound object is optional, whereas the type is mandatory, dually to regular binders. +.. _Coercions: Coercions --------- @@ -2201,43 +2125,38 @@ to coercions are provided in :ref:`implicitcoercions`. Printing constructions in full ------------------------------ +.. opt:: Printing All + Coercions, implicit arguments, the type of pattern-matching, but also notations (see :ref:`syntaxextensionsandinterpretationscopes`) can obfuscate the behavior of some tactics (typically the tactics applying to occurrences of subterms are -sensitive to the implicit arguments). The command - -.. cmd:: Set Printing All. - +sensitive to the implicit arguments). Turning this option on deactivates all high-level printing features such as coercions, implicit arguments, returned type of pattern-matching, notations and various syntactic sugar for pattern-matching or record projections. -Otherwise said, ``Set Printing All`` includes the effects of the commands -``Set Printing Implicit``, ``Set Printing Coercions``, ``Set Printing Synth``, -``Unset Printing Projections``, and ``Unset Printing Notations``. To reactivate -the high-level printing features, use the command +Otherwise said, :opt:`Printing All` includes the effects of the options +:opt:`Printing Implicit`, :opt:`Printing Coercions`, :opt:`Printing Synth`, +:opt:`Printing Projections`, and :opt:`Printing Notations`. To reactivate +the high-level printing features, use the command ``Unset Printing All``. -.. cmd:: Unset Printing All. +.. _printing-universes: Printing universes ------------------ -The following command: - -.. cmd:: Set Printing Universes. - -activates the display of the actual level of each occurrence of ``Type``. -See :ref:`TODO-4.1.1-sorts` for details. This wizard option, in combination -with ``Set Printing All`` (see :ref:`printing_constructions_full`) can help to diagnose failures -to unify terms apparently identical but internally different in the -Calculus of Inductive Constructions. To reactivate the display of the -actual level of the occurrences of Type, use +.. opt:: Printing Universes -.. cmd:: Unset Printing Universes. +Turn this option on to activate the display of the actual level of each +occurrence of :g:`Type`. See :ref:`Sorts` for details. This wizard option, in +combination with :opt:`Printing All` can help to diagnose failures to unify +terms apparently identical but internally different in the Calculus of Inductive +Constructions. The constraints on the internal level of the occurrences of Type -(see :ref:`TODO-4.1.1-sorts`) can be printed using the command +(see :ref:`Sorts`) can be printed using the command -.. cmd:: Print {? Sorted} Universes. +.. cmd:: Print {? Sorted} Universes + :name: Print Universes If the optional ``Sorted`` option is given, each universe will be made equivalent to a numbered label reflecting its level (with a linear @@ -2245,12 +2164,13 @@ ordering) in the universe hierarchy. This command also accepts an optional output filename: -.. cmd:: Print {? Sorted} Universes @string. +.. cmdv:: Print {? Sorted} Universes @string If `string` ends in ``.dot`` or ``.gv``, the constraints are printed in the DOT language, and can be processed by Graphviz tools. The format is unspecified if `string` doesn’t end in ``.dot`` or ``.gv``. +.. _existential-variables: Existential variables --------------------- @@ -2260,9 +2180,9 @@ subterms to eventually be replaced by actual subterms. Existential variables are generated in place of unsolvable implicit arguments or “_” placeholders when using commands such as ``Check`` (see -Section :ref:`TODO-6.3.1-check`) or when using tactics such as ``refine`` (see Section -:ref:`TODO-8.2.3-refine`), as well as in place of unsolvable instances when using -tactics such that ``eapply`` (see Section :ref:`TODO-8.2.4-apply`). An existential +Section :ref:`requests-to-the-environment`) or when using tactics such as +:tacn:`refine`, as well as in place of unsolvable instances when using +tactics such that :tacn:`eapply`. An existential variable is defined in a context, which is the context of variables of the placeholder which generated the existential variable, and a type, which is the expected type of the placeholder. @@ -2307,25 +2227,19 @@ existential variable used in the same context as its context of definition is wr Existential variables can be named by the user upon creation using the syntax ``?``\ `ident`. This is useful when the existential variable needs to be explicitly handled later in the script (e.g. -with a named-goal selector, see :ref:`TODO-9.2-goal-selectors`). +with a named-goal selector, see :ref:`goal-selectors`). .. _explicit-display-existentials: Explicit displaying of existential instances for pretty-printing ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -The command: - -.. cmd:: Set Printing Existential Instances. - -activates the full display of how the context of an existential -variable is instantiated at each of the occurrences of the existential -variable. +.. opt:: Printing Existential Instances -To deactivate the full display of the instances of existential -variables, use +This option (off by default) activates the full display of how the +context of an existential variable is instantiated at each of the +occurrences of the existential variable. -.. cmd:: Unset Printing Existential Instances. Solving existential variables using tactics ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -2338,7 +2252,7 @@ is not specified and is implementation-dependent. The inner tactic may use any variable defined in its scope, including repeated alternations between variables introduced by term binding as well as those introduced by tactic binding. The expression `tacexpr` can be any tactic -expression as described in :ref:`thetacticlanguage`. +expression as described in :ref:`ltac`. .. coqtop:: all @@ -2349,5 +2263,5 @@ using highly automated tactics without resorting to writing the proof-term by means of the interactive proof engine. This mechanism is comparable to the ``Declare Implicit Tactic`` command -defined at :ref:`TODO-8.9.7-implicit-automation`, except that the used +defined at :ref:`tactics-implicit-automation`, except that the used tactic is local to each hole instead of being declared globally. diff --git a/doc/sphinx/language/gallina-specification-language.rst b/doc/sphinx/language/gallina-specification-language.rst new file mode 100644 index 0000000000..c26ae2a93b --- /dev/null +++ b/doc/sphinx/language/gallina-specification-language.rst @@ -0,0 +1,1363 @@ +.. _gallinaspecificationlanguage: + +------------------------------------ + The Gallina specification language +------------------------------------ + +This chapter describes Gallina, the specification language of Coq. It allows +developing mathematical theories and to prove specifications of programs. The +theories are built from axioms, hypotheses, parameters, lemmas, theorems and +definitions of constants, functions, predicates and sets. The syntax of logical +objects involved in theories is described in Section :ref:`term`. The +language of commands, called *The Vernacular* is described in Section +:ref:`vernacular`. + +In Coq, logical objects are typed to ensure their logical correctness. The +rules implemented by the typing algorithm are described in Chapter :ref:`calculusofinductiveconstructions`. + + +About the grammars in the manual +================================ + +Grammars are presented in Backus-Naur form (BNF). Terminal symbols are +set in black ``typewriter font``. In addition, there are special notations for +regular expressions. + +An expression enclosed in square brackets ``[…]`` means at most one +occurrence of this expression (this corresponds to an optional +component). + +The notation “``entry sep … sep entry``” stands for a non empty sequence +of expressions parsed by entry and separated by the literal “``sep``” [1]_. + +Similarly, the notation “``entry … entry``” stands for a non empty +sequence of expressions parsed by the “``entry``” entry, without any +separator between. + +At the end, the notation “``[entry sep … sep entry]``” stands for a +possibly empty sequence of expressions parsed by the “``entry``” entry, +separated by the literal “``sep``”. + + +Lexical conventions +=================== + +Blanks + Space, newline and horizontal tabulation are considered as blanks. + Blanks are ignored but they separate tokens. + +Comments + Comments in Coq are enclosed between ``(*`` and ``*)``, and can be nested. + They can contain any character. However, :token:`string` literals must be + correctly closed. Comments are treated as blanks. + +Identifiers and access identifiers + Identifiers, written :token:`ident`, are sequences of letters, digits, ``_`` and + ``'``, that do not start with a digit or ``'``. That is, they are + recognized by the following lexical class: + + .. productionlist:: coq + first_letter : a..z ∣ A..Z ∣ _ ∣ unicode-letter + subsequent_letter : a..z ∣ A..Z ∣ 0..9 ∣ _ ∣ ' ∣ unicode-letter ∣ unicode-id-part + ident : `first_letter`[`subsequent_letter`…`subsequent_letter`] + access_ident : .`ident` + + All characters are meaningful. In particular, identifiers are case-sensitive. + The entry ``unicode-letter`` non-exhaustively includes Latin, + Greek, Gothic, Cyrillic, Arabic, Hebrew, Georgian, Hangul, Hiragana + and Katakana characters, CJK ideographs, mathematical letter-like + symbols, hyphens, non-breaking space, … The entry ``unicode-id-part`` + non-exhaustively includes symbols for prime letters and subscripts. + + Access identifiers, written :token:`access_ident`, are identifiers prefixed by + `.` (dot) without blank. They are used in the syntax of qualified + identifiers. + +Natural numbers and integers + Numerals are sequences of digits. Integers are numerals optionally + preceded by a minus sign. + + .. productionlist:: coq + digit : 0..9 + num : `digit`…`digit` + integer : [-]`num` + +Strings + Strings are delimited by ``"`` (double quote), and enclose a sequence of + any characters different from ``"`` or the sequence ``""`` to denote the + double quote character. In grammars, the entry for quoted strings is + :production:`string`. + +Keywords + The following identifiers are reserved keywords, and cannot be + employed otherwise:: + + _ as at cofix else end exists exists2 fix for + forall fun if IF in let match mod Prop return + Set then Type using where with + +Special tokens + The following sequences of characters are special tokens:: + + ! % & && ( () ) * + ++ , - -> . .( .. + / /\ : :: :< := :> ; < <- <-> <: <= <> = + => =_D > >-> >= ? ?= @ [ \/ ] ^ { | |- + || } ~ + + Lexical ambiguities are resolved according to the “longest match” + rule: when a sequence of non alphanumerical characters can be + decomposed into several different ways, then the first token is the + longest possible one (among all tokens defined at this moment), and so + on. + +.. _term: + +Terms +===== + +Syntax of terms +--------------- + +The following grammars describe the basic syntax of the terms of the +*Calculus of Inductive Constructions* (also called Cic). The formal +presentation of Cic is given in Chapter :ref:`calculusofinductiveconstructions`. Extensions of this syntax +are given in Chapter :ref:`extensionsofgallina`. How to customize the syntax +is described in Chapter :ref:`syntaxextensionsandinterpretationscopes`. + +.. productionlist:: coq + term : forall `binders` , `term` + : | fun `binders` => `term` + : | fix `fix_bodies` + : | cofix `cofix_bodies` + : | let `ident` [`binders`] [: `term`] := `term` in `term` + : | let fix `fix_body` in `term` + : | let cofix `cofix_body` in `term` + : | let ( [`name` , … , `name`] ) [`dep_ret_type`] := `term` in `term` + : | let ' `pattern` [in `term`] := `term` [`return_type`] in `term` + : | if `term` [`dep_ret_type`] then `term` else `term` + : | `term` : `term` + : | `term` <: `term` + : | `term` :> + : | `term` -> `term` + : | `term` `arg` … `arg` + : | @ `qualid` [`term` … `term`] + : | `term` % `ident` + : | match `match_item` , … , `match_item` [`return_type`] with + : [[|] `equation` | … | `equation`] end + : | `qualid` + : | `sort` + : | `num` + : | _ + : | ( `term` ) + arg : `term` + : | ( `ident` := `term` ) + binders : `binder` … `binder` + binder : `name` + : | ( `name` … `name` : `term` ) + : | ( `name` [: `term`] := `term` ) + : | ' `pattern` + name : `ident` | _ + qualid : `ident` | `qualid` `access_ident` + sort : Prop | Set | Type + fix_bodies : `fix_body` + : | `fix_body` with `fix_body` with … with `fix_body` for `ident` + cofix_bodies : `cofix_body` + : | `cofix_body` with `cofix_body` with … with `cofix_body` for `ident` + fix_body : `ident` `binders` [`annotation`] [: `term`] := `term` + cofix_body : `ident` [`binders`] [: `term`] := `term` + annotation : { struct `ident` } + match_item : `term` [as `name`] [in `qualid` [`pattern` … `pattern`]] + dep_ret_type : [as `name`] `return_type` + return_type : return `term` + equation : `mult_pattern` | … | `mult_pattern` => `term` + mult_pattern : `pattern` , … , `pattern` + pattern : `qualid` `pattern` … `pattern` + : | @ `qualid` `pattern` … `pattern` + : | `pattern` as `ident` + : | `pattern` % `ident` + : | `qualid` + : | _ + : | `num` + : | ( `or_pattern` , … , `or_pattern` ) + or_pattern : `pattern` | … | `pattern` + + +Types +----- + +Coq terms are typed. Coq types are recognized by the same syntactic +class as :token:`term`. We denote by :production:`type` the semantic subclass +of types inside the syntactic class :token:`term`. + +.. _gallina-identifiers: + +Qualified identifiers and simple identifiers +-------------------------------------------- + +*Qualified identifiers* (:token:`qualid`) denote *global constants* +(definitions, lemmas, theorems, remarks or facts), *global variables* +(parameters or axioms), *inductive types* or *constructors of inductive +types*. *Simple identifiers* (or shortly :token:`ident`) are a syntactic subset +of qualified identifiers. Identifiers may also denote *local variables*, +while qualified identifiers do not. + +Numerals +-------- + +Numerals have no definite semantics in the calculus. They are mere +notations that can be bound to objects through the notation mechanism +(see Chapter :ref:`syntaxextensionsandinterpretationscopes` for details). +Initially, numerals are bound to Peano’s representation of natural +numbers (see :ref:`datatypes`). + +.. note:: + + Negative integers are not at the same level as :token:`num`, for this + would make precedence unnatural. + +Sorts +----- + +There are three sorts :g:`Set`, :g:`Prop` and :g:`Type`. + +- :g:`Prop` is the universe of *logical propositions*. The logical propositions + themselves are typing the proofs. We denote propositions by :production:`form`. + This constitutes a semantic subclass of the syntactic class :token:`term`. + +- :g:`Set` is is the universe of *program types* or *specifications*. The + specifications themselves are typing the programs. We denote + specifications by :production:`specif`. This constitutes a semantic subclass of + the syntactic class :token:`term`. + +- :g:`Type` is the type of :g:`Prop` and :g:`Set` + +More on sorts can be found in Section :ref:`sorts`. + +.. _binders: + +Binders +------- + +Various constructions such as :g:`fun`, :g:`forall`, :g:`fix` and :g:`cofix` +*bind* variables. A binding is represented by an identifier. If the binding +variable is not used in the expression, the identifier can be replaced by the +symbol :g:`_`. When the type of a bound variable cannot be synthesized by the +system, it can be specified with the notation :n:`(@ident : @type)`. There is also +a notation for a sequence of binding variables sharing the same type: +:n:`({+ @ident} : @type)`. A +binder can also be any pattern prefixed by a quote, e.g. :g:`'(x,y)`. + +Some constructions allow the binding of a variable to value. This is +called a “let-binder”. The entry :token:`binder` of the grammar accepts +either an assumption binder as defined above or a let-binder. The notation in +the latter case is :n:`(@ident := @term)`. In a let-binder, only one +variable can be introduced at the same time. It is also possible to give +the type of the variable as follows: +:n:`(@ident : @type := @term)`. + +Lists of :token:`binder` are allowed. In the case of :g:`fun` and :g:`forall`, +it is intended that at least one binder of the list is an assumption otherwise +fun and forall gets identical. Moreover, parentheses can be omitted in +the case of a single sequence of bindings sharing the same type (e.g.: +:g:`fun (x y z : A) => t` can be shortened in :g:`fun x y z : A => t`). + +Abstractions +------------ + +The expression :n:`fun @ident : @type => @term` defines the +*abstraction* of the variable :token:`ident`, of type :token:`type`, over the term +:token:`term`. It denotes a function of the variable :token:`ident` that evaluates to +the expression :token:`term` (e.g. :g:`fun x : A => x` denotes the identity +function on type :g:`A`). The keyword :g:`fun` can be followed by several +binders as given in Section :ref:`binders`. Functions over +several variables are equivalent to an iteration of one-variable +functions. For instance the expression +“fun :token:`ident`\ :math:`_{1}` … :token:`ident`\ :math:`_{n}` +: :token:`type` => :token:`term`” +denotes the same function as “ fun :token:`ident`\ +:math:`_{1}` : :token:`type` => … +fun :token:`ident`\ :math:`_{n}` : :token:`type` => :token:`term`”. If +a let-binder occurs in +the list of binders, it is expanded to a let-in definition (see +Section :ref:`let-in`). + +Products +-------- + +The expression :n:`forall @ident : @type, @term` denotes the +*product* of the variable :token:`ident` of type :token:`type`, over the term :token:`term`. +As for abstractions, :g:`forall` is followed by a binder list, and products +over several variables are equivalent to an iteration of one-variable +products. Note that :token:`term` is intended to be a type. + +If the variable :token:`ident` occurs in :token:`term`, the product is called +*dependent product*. The intention behind a dependent product +:g:`forall x : A, B` is twofold. It denotes either +the universal quantification of the variable :g:`x` of type :g:`A` +in the proposition :g:`B` or the functional dependent product from +:g:`A` to :g:`B` (a construction usually written +:math:`\Pi_{x:A}.B` in set theory). + +Non dependent product types have a special notation: :g:`A -> B` stands for +:g:`forall _ : A, B`. The *non dependent product* is used both to denote +the propositional implication and function types. + +Applications +------------ + +The expression :token:`term`\ :math:`_0` :token:`term`\ :math:`_1` denotes the +application of :token:`term`\ :math:`_0` to :token:`term`\ :math:`_1`. + +The expression :token:`term`\ :math:`_0` :token:`term`\ :math:`_1` ... +:token:`term`\ :math:`_n` denotes the application of the term +:token:`term`\ :math:`_0` to the arguments :token:`term`\ :math:`_1` ... then +:token:`term`\ :math:`_n`. It is equivalent to ( … ( :token:`term`\ :math:`_0` +:token:`term`\ :math:`_1` ) … ) :token:`term`\ :math:`_n` : associativity is to the +left. + +The notation :n:`(@ident := @term)` for arguments is used for making +explicit the value of implicit arguments (see +Section :ref:`explicit-applications`). + +Type cast +--------- + +The expression :n:`@term : @type` is a type cast expression. It enforces +the type of :token:`term` to be :token:`type`. + +:n:`@term <: @type` locally sets up the virtual machine for checking that +:token:`term` has type :token:`type`. + +Inferable subterms +------------------ + +Expressions often contain redundant pieces of information. Subterms that can be +automatically inferred by Coq can be replaced by the symbol ``_`` and Coq will +guess the missing piece of information. + +.. _let-in: + +Let-in definitions +------------------ + +:n:`let @ident := @term in @term’` +denotes the local binding of :token:`term` to the variable +:token:`ident` in :token:`term`’. There is a syntactic sugar for let-in +definition of functions: :n:`let @ident {+ @binder} := @term in @term’` +stands for :n:`let @ident := fun {+ @binder} => @term in @term’`. + +Definition by case analysis +--------------------------- + +Objects of inductive types can be destructurated by a case-analysis +construction called *pattern-matching* expression. A pattern-matching +expression is used to analyze the structure of an inductive object and +to apply specific treatments accordingly. + +This paragraph describes the basic form of pattern-matching. See +Section :ref:`Mult-match` and Chapter :ref:`extendedpatternmatching` for the description +of the general form. The basic form of pattern-matching is characterized +by a single :token:`match_item` expression, a :token:`mult_pattern` restricted to a +single :token:`pattern` and :token:`pattern` restricted to the form +:n:`@qualid {* @ident}`. + +The expression match ":token:`term`:math:`_0` :token:`return_type` with +:token:`pattern`:math:`_1` => :token:`term`:math:`_1` :math:`|` … :math:`|` +:token:`pattern`:math:`_n` => :token:`term`:math:`_n` end" denotes a +*pattern-matching* over the term :token:`term`:math:`_0` (expected to be +of an inductive type :math:`I`). The terms :token:`term`:math:`_1`\ …\ +:token:`term`:math:`_n` are the *branches* of the pattern-matching +expression. Each of :token:`pattern`:math:`_i` has a form :token:`qualid` +:token:`ident` where :token:`qualid` must denote a constructor. There should be +exactly one branch for every constructor of :math:`I`. + +The :token:`return_type` expresses the type returned by the whole match +expression. There are several cases. In the *non dependent* case, all +branches have the same type, and the :token:`return_type` is the common type of +branches. In this case, :token:`return_type` can usually be omitted as it can be +inferred from the type of the branches [2]_. + +In the *dependent* case, there are three subcases. In the first subcase, +the type in each branch may depend on the exact value being matched in +the branch. In this case, the whole pattern-matching itself depends on +the term being matched. This dependency of the term being matched in the +return type is expressed with an “as :token:`ident`” clause where :token:`ident` +is dependent in the return type. For instance, in the following example: + +.. coqtop:: in + + Inductive bool : Type := true : bool | false : bool. + Inductive eq (A:Type) (x:A) : A -> Prop := eq_refl : eq A x x. + Inductive or (A:Prop) (B:Prop) : Prop := + | or_introl : A -> or A B + | or_intror : B -> or A B. + + Definition bool_case (b:bool) : or (eq bool b true) (eq bool b false) := + match b as x return or (eq bool x true) (eq bool x false) with + | true => or_introl (eq bool true true) (eq bool true false) (eq_refl bool true) + | false => or_intror (eq bool false true) (eq bool false false) (eq_refl bool false) + end. + +the branches have respective types ":g:`or (eq bool true true) (eq bool true false)`" +and ":g:`or (eq bool false true) (eq bool false false)`" while the whole +pattern-matching expression has type ":g:`or (eq bool b true) (eq bool b false)`", +the identifier :g:`b` being used to represent the dependency. + +.. note:: + + When the term being matched is a variable, the ``as`` clause can be + omitted and the term being matched can serve itself as binding name in + the return type. For instance, the following alternative definition is + accepted and has the same meaning as the previous one. + + .. coqtop:: in + + Definition bool_case (b:bool) : or (eq bool b true) (eq bool b false) := + match b return or (eq bool b true) (eq bool b false) with + | true => or_introl (eq bool true true) (eq bool true false) (eq_refl bool true) + | false => or_intror (eq bool false true) (eq bool false false) (eq_refl bool false) + end. + +The second subcase is only relevant for annotated inductive types such +as the equality predicate (see Section :ref:`coq-equality`), +the order predicate on natural numbers or the type of lists of a given +length (see Section :ref:`matching-dependent`). In this configuration, the +type of each branch can depend on the type dependencies specific to the +branch and the whole pattern-matching expression has a type determined +by the specific dependencies in the type of the term being matched. This +dependency of the return type in the annotations of the inductive type +is expressed using a “:g:`in` :math:`I` :g:`_ … _` :token:`pattern`:math:`_1` … +:token:`pattern`:math:`_n`” clause, where + +- :math:`I` is the inductive type of the term being matched; + +- the :g:`_` are matching the parameters of the inductive type: the + return type is not dependent on them. + +- the :token:`pattern`:math:`_i` are matching the annotations of the + inductive type: the return type is dependent on them + +- in the basic case which we describe below, each :token:`pattern`:math:`_i` + is a name :token:`ident`:math:`_i`; see :ref:`match-in-patterns` for the + general case + +For instance, in the following example: + +.. coqtop:: in + + Definition eq_sym (A:Type) (x y:A) (H:eq A x y) : eq A y x := + match H in eq _ _ z return eq A z x with + | eq_refl _ => eq_refl A x + end. + +the type of the branch is :g:`eq A x x` because the third argument of +:g:`eq` is :g:`x` in the type of the pattern :g:`eq_refl`. On the contrary, the +type of the whole pattern-matching expression has type :g:`eq A y x` because the +third argument of eq is y in the type of H. This dependency of the case analysis +in the third argument of :g:`eq` is expressed by the identifier :g:`z` in the +return type. + +Finally, the third subcase is a combination of the first and second +subcase. In particular, it only applies to pattern-matching on terms in +a type with annotations. For this third subcase, both the clauses ``as`` and +``in`` are available. + +There are specific notations for case analysis on types with one or two +constructors: ``if … then … else …`` and ``let (…,…) := … in …`` (see +Sections :ref:`if-then-else` and :ref:`irrefutable-patterns`). + +Recursive functions +------------------- + +The expression “``fix`` :token:`ident`:math:`_1` :token:`binder`:math:`_1` ``:`` +:token:`type`:math:`_1` ``:=`` :token:`term`:math:`_1` ``with … with`` +:token:`ident`:math:`_n` :token:`binder`:math:`_n` : :token:`type`:math:`_n` +``:=`` :token:`term`:math:`_n` ``for`` :token:`ident`:math:`_i`” denotes the +:math:`i`-th component of a block of functions defined by mutual structural +recursion. It is the local counterpart of the :cmd:`Fixpoint` command. When +:math:`n=1`, the “``for`` :token:`ident`:math:`_i`” clause is omitted. + +The expression “``cofix`` :token:`ident`:math:`_1` :token:`binder`:math:`_1` ``:`` +:token:`type`:math:`_1` ``with … with`` :token:`ident`:math:`_n` :token:`binder`:math:`_n` +: :token:`type`:math:`_n` ``for`` :token:`ident`:math:`_i`” denotes the +:math:`i`-th component of a block of terms defined by a mutual guarded +co-recursion. It is the local counterpart of the :cmd:`CoFixpoint` command. When +:math:`n=1`, the “``for`` :token:`ident`:math:`_i`” clause is omitted. + +The association of a single fixpoint and a local definition have a special +syntax: :n:`let fix @ident @binders := @term in` stands for +:n:`let @ident := fix @ident @binders := @term in`. The same applies for co-fixpoints. + +.. _vernacular: + +The Vernacular +============== + +.. productionlist:: coq + sentence : `assumption` + : | `definition` + : | `inductive` + : | `fixpoint` + : | `assertion` `proof` + assumption : `assumption_keyword` `assums`. + assumption_keyword : Axiom | Conjecture + : | Parameter | Parameters + : | Variable | Variables + : | Hypothesis | Hypotheses + assums : `ident` … `ident` : `term` + : | ( `ident` … `ident` : `term` ) … ( `ident` … `ident` : `term` ) + definition : [Local] Definition `ident` [`binders`] [: `term`] := `term` . + : | Let `ident` [`binders`] [: `term`] := `term` . + inductive : Inductive `ind_body` with … with `ind_body` . + : | CoInductive `ind_body` with … with `ind_body` . + ind_body : `ident` [`binders`] : `term` := + : [[|] `ident` [`binders`] [:`term`] | … | `ident` [`binders`] [:`term`]] + fixpoint : Fixpoint `fix_body` with … with `fix_body` . + : | CoFixpoint `cofix_body` with … with `cofix_body` . + assertion : `assertion_keyword` `ident` [`binders`] : `term` . + assertion_keyword : Theorem | Lemma + : | Remark | Fact + : | Corollary | Proposition + : | Definition | Example + proof : Proof . … Qed . + : | Proof . … Defined . + : | Proof . … Admitted . + +.. todo:: This use of … in this grammar is inconsistent + What about removing the proof part of this grammar from this chapter + and putting it somewhere where top-level tactics can be described as well? + See also #7583. + +This grammar describes *The Vernacular* which is the language of +commands of Gallina. A sentence of the vernacular language, like in +many natural languages, begins with a capital letter and ends with a +dot. + +The different kinds of command are described hereafter. They all suppose +that the terms occurring in the sentences are well-typed. + +.. _gallina-assumptions: + +Assumptions +----------- + +Assumptions extend the environment with axioms, parameters, hypotheses +or variables. An assumption binds an :token:`ident` to a :token:`type`. It is accepted +by Coq if and only if this :token:`type` is a correct type in the environment +preexisting the declaration and if :token:`ident` was not previously defined in +the same module. This :token:`type` is considered to be the type (or +specification, or statement) assumed by :token:`ident` and we say that :token:`ident` +has type :token:`type`. + +.. _Axiom: + +.. cmd:: Parameter @ident : @type + + This command links :token:`type` to the name :token:`ident` as its specification in + the global context. The fact asserted by :token:`type` is thus assumed as a + postulate. + + .. exn:: @ident already exists. + :name: @ident already exists. (Axiom) + :undocumented: + + .. cmdv:: Parameter {+ @ident } : @type + + Adds several parameters with specification :token:`type`. + + .. cmdv:: Parameter {+ ( {+ @ident } : @type ) } + + Adds blocks of parameters with different specifications. + + .. cmdv:: Local Parameter {+ ( {+ @ident } : @type ) } + :name: Local Parameter + + Such parameters are never made accessible through their unqualified name by + :cmd:`Import` and its variants. You have to explicitly give their fully + qualified name to refer to them. + + .. cmdv:: {? Local } Parameters {+ ( {+ @ident } : @type ) } + {? Local } Axiom {+ ( {+ @ident } : @type ) } + {? Local } Axioms {+ ( {+ @ident } : @type ) } + {? Local } Conjecture {+ ( {+ @ident } : @type ) } + {? Local } Conjectures {+ ( {+ @ident } : @type ) } + :name: Parameters; Axiom; Axioms; Conjecture; Conjectures + + These variants are synonyms of :n:`{? Local } Parameter {+ ( {+ @ident } : @type ) }`. + +.. cmd:: Variable @ident : @type + + This command links :token:`type` to the name :token:`ident` in the context of + the current section (see Section :ref:`section-mechanism` for a description of + the section mechanism). When the current section is closed, name :token:`ident` + will be unknown and every object using this variable will be explicitly + parametrized (the variable is *discharged*). Using the :cmd:`Variable` command out + of any section is equivalent to using :cmd:`Local Parameter`. + + .. exn:: @ident already exists. + :name: @ident already exists. (Variable) + :undocumented: + + .. cmdv:: Variable {+ @ident } : @term + + Links :token:`type` to each :token:`ident`. + + .. cmdv:: Variable {+ ( {+ @ident } : @term ) } + + Adds blocks of variables with different specifications. + + .. cmdv:: Variables {+ ( {+ @ident } : @term) } + Hypothesis {+ ( {+ @ident } : @term) } + Hypotheses {+ ( {+ @ident } : @term) } + :name: Variables; Hypothesis; Hypotheses + + These variants are synonyms of :n:`Variable {+ ( {+ @ident } : @term) }`. + +.. note:: + It is advised to use the commands :cmd:`Axiom`, :cmd:`Conjecture` and + :cmd:`Hypothesis` (and their plural forms) for logical postulates (i.e. when + the assertion :token:`type` is of sort :g:`Prop`), and to use the commands + :cmd:`Parameter` and :cmd:`Variable` (and their plural forms) in other cases + (corresponding to the declaration of an abstract mathematical entity). + +.. _gallina-definitions: + +Definitions +----------- + +Definitions extend the environment with associations of names to terms. +A definition can be seen as a way to give a meaning to a name or as a +way to abbreviate a term. In any case, the name can later be replaced at +any time by its definition. + +The operation of unfolding a name into its definition is called +:math:`\delta`-conversion (see Section :ref:`delta-reduction`). A +definition is accepted by the system if and only if the defined term is +well-typed in the current context of the definition and if the name is +not already used. The name defined by the definition is called a +*constant* and the term it refers to is its *body*. A definition has a +type which is the type of its body. + +A formal presentation of constants and environments is given in +Section :ref:`typing-rules`. + +.. cmd:: Definition @ident := @term + + This command binds :token:`term` to the name :token:`ident` in the environment, + provided that :token:`term` is well-typed. + + .. exn:: @ident already exists. + :name: @ident already exists. (Definition) + :undocumented: + + .. cmdv:: Definition @ident : @type := @term + + This variant checks that the type of :token:`term` is definitionally equal to + :token:`type`, and registers :token:`ident` as being of type + :token:`type`, and bound to value :token:`term`. + + .. exn:: The term @term has type @type while it is expected to have type @type'. + :undocumented: + + .. cmdv:: Definition @ident @binders {? : @term } := @term + + This is equivalent to + :n:`Definition @ident : forall @binders, @term := fun @binders => @term`. + + .. cmdv:: Local Definition @ident {? @binders } {? : @type } := @term + :name: Local Definition + + Such definitions are never made accessible through their + unqualified name by :cmd:`Import` and its variants. + You have to explicitly give their fully qualified name to refer to them. + + .. cmdv:: {? Local } Example @ident {? @binders } {? : @type } := @term + :name: Example + + This is equivalent to :cmd:`Definition`. + +.. seealso:: :cmd:`Opaque`, :cmd:`Transparent`, :tacn:`unfold`. + +.. cmd:: Let @ident := @term + + This command binds the value :token:`term` to the name :token:`ident` in the + environment of the current section. The name :token:`ident` disappears when the + current section is eventually closed, and all persistent objects (such + as theorems) defined within the section and depending on :token:`ident` are + prefixed by the let-in definition :n:`let @ident := @term in`. + Using the :cmd:`Let` command out of any section is equivalent to using + :cmd:`Local Definition`. + + .. exn:: @ident already exists. + :name: @ident already exists. (Let) + :undocumented: + + .. cmdv:: Let @ident {? @binders } {? : @type } := @term + :undocumented: + + .. cmdv:: Let Fixpoint @ident @fix_body {* with @fix_body} + :name: Let Fixpoint + :undocumented: + + .. cmdv:: Let CoFixpoint @ident @cofix_body {* with @cofix_body} + :name: Let CoFixpoint + :undocumented: + +.. seealso:: Section :ref:`section-mechanism`, commands :cmd:`Opaque`, + :cmd:`Transparent`, and tactic :tacn:`unfold`. + +.. _gallina-inductive-definitions: + +Inductive definitions +--------------------- + +We gradually explain simple inductive types, simple annotated inductive +types, simple parametric inductive types, mutually inductive types. We +explain also co-inductive types. + +Simple inductive types +~~~~~~~~~~~~~~~~~~~~~~ + +.. cmd:: Inductive @ident : {? @sort } := {? | } @ident : @type {* | @ident : @type } + + This command defines a simple inductive type and its constructors. + The first :token:`ident` is the name of the inductively defined type + and :token:`sort` is the universe where it lives. The next :token:`ident`\s + are the names of its constructors and :token:`type` their respective types. + Depending on the universe where the inductive type :token:`ident` lives + (e.g. its type :token:`sort`), Coq provides a number of destructors. + Destructors are named :token:`ident`\ ``_ind``, :token:`ident`\ ``_rec`` + or :token:`ident`\ ``_rect`` which respectively correspond to elimination + principles on :g:`Prop`, :g:`Set` and :g:`Type`. + The type of the destructors expresses structural induction/recursion + principles over objects of type :token:`ident`. + The constant :token:`ident`\ ``_ind`` is always provided, + whereas :token:`ident`\ ``_rec`` and :token:`ident`\ ``_rect`` can be + impossible to derive (for example, when :token:`ident` is a proposition). + + .. exn:: Non strictly positive occurrence of @ident in @type. + + The types of the constructors have to satisfy a *positivity condition* + (see Section :ref:`positivity`). This condition ensures the soundness of + the inductive definition. + + .. exn:: The conclusion of @type is not valid; it must be built from @ident. + + The conclusion of the type of the constructors must be the inductive type + :token:`ident` being defined (or :token:`ident` applied to arguments in + the case of annotated inductive types — cf. next section). + + .. example:: + The set of natural numbers is defined as: + + .. coqtop:: all + + Inductive nat : Set := + | O : nat + | S : nat -> nat. + + The type nat is defined as the least :g:`Set` containing :g:`O` and closed by + the :g:`S` constructor. The names :g:`nat`, :g:`O` and :g:`S` are added to the + environment. + + Now let us have a look at the elimination principles. They are three of them: + :g:`nat_ind`, :g:`nat_rec` and :g:`nat_rect`. The type of :g:`nat_ind` is: + + .. coqtop:: all + + Check nat_ind. + + This is the well known structural induction principle over natural + numbers, i.e. the second-order form of Peano’s induction principle. It + allows proving some universal property of natural numbers (:g:`forall + n:nat, P n`) by induction on :g:`n`. + + The types of :g:`nat_rec` and :g:`nat_rect` are similar, except that they pertain + to :g:`(P:nat->Set)` and :g:`(P:nat->Type)` respectively. They correspond to + primitive induction principles (allowing dependent types) respectively + over sorts ``Set`` and ``Type``. + + .. cmdv:: Inductive @ident {? : @sort } := {? | } {*| @ident {? @binders } {? : @type } } + + Constructors :token:`ident`\s can come with :token:`binders` in which case, + the actual type of the constructor is :n:`forall @binders, @type`. + + In the case where inductive types have no annotations (next section + gives an example of such annotations), a constructor can be defined + by only giving the type of its arguments. + + .. example:: + + .. coqtop:: in + + Inductive nat : Set := O | S (_:nat). + + +Simple annotated inductive types +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +In an annotated inductive types, the universe where the inductive type +is defined is no longer a simple sort, but what is called an arity, +which is a type whose conclusion is a sort. + +.. example:: + + As an example of annotated inductive types, let us define the + :g:`even` predicate: + + .. coqtop:: all + + Inductive even : nat -> Prop := + | even_0 : even O + | even_SS : forall n:nat, even n -> even (S (S n)). + + The type :g:`nat->Prop` means that even is a unary predicate (inductively + defined) over natural numbers. The type of its two constructors are the + defining clauses of the predicate even. The type of :g:`even_ind` is: + + .. coqtop:: all + + Check even_ind. + + From a mathematical point of view it asserts that the natural numbers satisfying + the predicate even are exactly in the smallest set of naturals satisfying the + clauses :g:`even_0` or :g:`even_SS`. This is why, when we want to prove any + predicate :g:`P` over elements of :g:`even`, it is enough to prove it for :g:`O` + and to prove that if any natural number :g:`n` satisfies :g:`P` its double + successor :g:`(S (S n))` satisfies also :g:`P`. This is indeed analogous to the + structural induction principle we got for :g:`nat`. + +Parametrized inductive types +~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +.. cmdv:: Inductive @ident @binders {? : @type } := {? | } @ident : @type {* | @ident : @type} + + In the previous example, each constructor introduces a different + instance of the predicate :g:`even`. In some cases, all the constructors + introduce the same generic instance of the inductive definition, in + which case, instead of an annotation, we use a context of parameters + which are :token:`binders` shared by all the constructors of the definition. + + Parameters differ from inductive type annotations in the fact that the + conclusion of each type of constructor invoke the inductive type with + the same values of parameters as its specification. + + .. example:: + + A typical example is the definition of polymorphic lists: + + .. coqtop:: in + + Inductive list (A:Set) : Set := + | nil : list A + | cons : A -> list A -> list A. + + In the type of :g:`nil` and :g:`cons`, we write :g:`(list A)` and not + just :g:`list`. The constructors :g:`nil` and :g:`cons` will have respectively + types: + + .. coqtop:: all + + Check nil. + Check cons. + + Types of destructors are also quantified with :g:`(A:Set)`. + + Once again, it is possible to specify only the type of the arguments + of the constructors, and to omit the type of the conclusion: + + .. coqtop:: in + + Inductive list (A:Set) : Set := nil | cons (_:A) (_:list A). + +.. note:: + + It is possible in the type of a constructor, to + invoke recursively the inductive definition on an argument which is not + the parameter itself. + + One can define : + + .. coqtop:: all + + Inductive list2 (A:Set) : Set := + | nil2 : list2 A + | cons2 : A -> list2 (A*A) -> list2 A. + + that can also be written by specifying only the type of the arguments: + + .. coqtop:: all reset + + Inductive list2 (A:Set) : Set := nil2 | cons2 (_:A) (_:list2 (A*A)). + + But the following definition will give an error: + + .. coqtop:: all + + Fail Inductive listw (A:Set) : Set := + | nilw : listw (A*A) + | consw : A -> listw (A*A) -> listw (A*A). + + because the conclusion of the type of constructors should be :g:`listw A` + in both cases. + + + A parametrized inductive definition can be defined using annotations + instead of parameters but it will sometimes give a different (bigger) + sort for the inductive definition and will produce a less convenient + rule for case elimination. + +.. seealso:: + Section :ref:`inductive-definitions` and the :tacn:`induction` tactic. + +Variants +~~~~~~~~ + +.. cmd:: Variant @ident @binders {? : @type } := {? | } @ident : @type {* | @ident : @type} + + The :cmd:`Variant` command is identical to the :cmd:`Inductive` command, except + that it disallows recursive definition of types (for instance, lists cannot + be defined using :cmd:`Variant`). No induction scheme is generated for + this variant, unless option :opt:`Nonrecursive Elimination Schemes` is on. + + .. exn:: The @num th argument of @ident must be @ident in @type. + :undocumented: + +Mutually defined inductive types +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +.. cmdv:: Inductive @ident {? : @type } := {? | } {*| @ident : @type } {* with {? | } {*| @ident {? : @type } } } + + This variant allows defining a block of mutually inductive types. + It has the same semantics as the above :cmd:`Inductive` definition for each + :token:`ident`. All :token:`ident` are simultaneously added to the environment. + Then well-typing of constructors can be checked. Each one of the :token:`ident` + can be used on its own. + + .. cmdv:: Inductive @ident @binders {? : @type } := {? | } {*| @ident : @type } {* with {? | } {*| @ident @binders {? : @type } } } + + In this variant, the inductive definitions are parametrized + with :token:`binders`. However, parameters correspond to a local context + in which the whole set of inductive declarations is done. For this + reason, the parameters must be strictly the same for each inductive types. + +.. example:: + The typical example of a mutual inductive data type is the one for trees and + forests. We assume given two types :g:`A` and :g:`B` as variables. It can + be declared the following way. + + .. coqtop:: in + + Variables A B : Set. + + Inductive tree : Set := node : A -> forest -> tree + + with forest : Set := + | leaf : B -> forest + | cons : tree -> forest -> forest. + + This declaration generates automatically six induction principles. They are + respectively called :g:`tree_rec`, :g:`tree_ind`, :g:`tree_rect`, + :g:`forest_rec`, :g:`forest_ind`, :g:`forest_rect`. These ones are not the most + general ones but are just the induction principles corresponding to each + inductive part seen as a single inductive definition. + + To illustrate this point on our example, we give the types of :g:`tree_rec` + and :g:`forest_rec`. + + .. coqtop:: all + + Check tree_rec. + + Check forest_rec. + + Assume we want to parametrize our mutual inductive definitions with the + two type variables :g:`A` and :g:`B`, the declaration should be + done the following way: + + .. coqtop:: in + + Inductive tree (A B:Set) : Set := node : A -> forest A B -> tree A B + + with forest (A B:Set) : Set := + | leaf : B -> forest A B + | cons : tree A B -> forest A B -> forest A B. + + Assume we define an inductive definition inside a section + (cf. :ref:`section-mechanism`). When the section is closed, the variables + declared in the section and occurring free in the declaration are added as + parameters to the inductive definition. + +.. seealso:: + A generic command :cmd:`Scheme` is useful to build automatically various + mutual induction principles. + +.. _coinductive-types: + +Co-inductive types +~~~~~~~~~~~~~~~~~~ + +The objects of an inductive type are well-founded with respect to the +constructors of the type. In other words, such objects contain only a +*finite* number of constructors. Co-inductive types arise from relaxing +this condition, and admitting types whose objects contain an infinity of +constructors. Infinite objects are introduced by a non-ending (but +effective) process of construction, defined in terms of the constructors +of the type. + +.. cmd:: CoInductive @ident @binders {? : @type } := {? | } @ident : @type {* | @ident : @type} + + This command introduces a co-inductive type. + The syntax of the command is the same as the command :cmd:`Inductive`. + No principle of induction is derived from the definition of a co-inductive + type, since such principles only make sense for inductive types. + For co-inductive types, the only elimination principle is case analysis. + +.. example:: + An example of a co-inductive type is the type of infinite sequences of + natural numbers, usually called streams. + + .. coqtop:: in + + CoInductive Stream : Set := Seq : nat -> Stream -> Stream. + + The usual destructors on streams :g:`hd:Stream->nat` and :g:`tl:Str->Str` + can be defined as follows: + + .. coqtop:: in + + Definition hd (x:Stream) := let (a,s) := x in a. + Definition tl (x:Stream) := let (a,s) := x in s. + +Definition of co-inductive predicates and blocks of mutually +co-inductive definitions are also allowed. + +.. example:: + An example of a co-inductive predicate is the extensional equality on + streams: + + .. coqtop:: in + + CoInductive EqSt : Stream -> Stream -> Prop := + eqst : forall s1 s2:Stream, + hd s1 = hd s2 -> EqSt (tl s1) (tl s2) -> EqSt s1 s2. + + In order to prove the extensional equality of two streams :g:`s1` and :g:`s2` + we have to construct an infinite proof of equality, that is, an infinite + object of type :g:`(EqSt s1 s2)`. We will see how to introduce infinite + objects in Section :ref:`cofixpoint`. + +Definition of recursive functions +--------------------------------- + +Definition of functions by recursion over inductive objects +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +This section describes the primitive form of definition by recursion over +inductive objects. See the :cmd:`Function` command for more advanced +constructions. + +.. _Fixpoint: + +.. cmd:: Fixpoint @ident @binders {? {struct @ident} } {? : @type } := @term + + This command allows defining functions by pattern-matching over inductive + objects using a fixed point construction. The meaning of this declaration is + to define :token:`ident` a recursive function with arguments specified by + the :token:`binders` such that :token:`ident` applied to arguments + corresponding to these :token:`binders` has type :token:`type`, and is + equivalent to the expression :token:`term`. The type of :token:`ident` is + consequently :n:`forall @binders, @type` and its value is equivalent + to :n:`fun @binders => @term`. + + To be accepted, a :cmd:`Fixpoint` definition has to satisfy some syntactical + constraints on a special argument called the decreasing argument. They + are needed to ensure that the :cmd:`Fixpoint` definition always terminates. + The point of the :n:`{struct @ident}` annotation is to let the user tell the + system which argument decreases along the recursive calls. + + The :n:`{struct @ident}` annotation may be left implicit, in this case the + system tries successively arguments from left to right until it finds one + that satisfies the decreasing condition. + + .. note:: + + + Some fixpoints may have several arguments that fit as decreasing + arguments, and this choice influences the reduction of the fixpoint. + Hence an explicit annotation must be used if the leftmost decreasing + argument is not the desired one. Writing explicit annotations can also + speed up type-checking of large mutual fixpoints. + + + In order to keep the strong normalization property, the fixed point + reduction will only be performed when the argument in position of the + decreasing argument (which type should be in an inductive definition) + starts with a constructor. + + + .. example:: + One can define the addition function as : + + .. coqtop:: all + + Fixpoint add (n m:nat) {struct n} : nat := + match n with + | O => m + | S p => S (add p m) + end. + + The match operator matches a value (here :g:`n`) with the various + constructors of its (inductive) type. The remaining arguments give the + respective values to be returned, as functions of the parameters of the + corresponding constructor. Thus here when :g:`n` equals :g:`O` we return + :g:`m`, and when :g:`n` equals :g:`(S p)` we return :g:`(S (add p m))`. + + The match operator is formally described in + Section :ref:`match-construction`. + The system recognizes that in the inductive call :g:`(add p m)` the first + argument actually decreases because it is a *pattern variable* coming + from :g:`match n with`. + + .. example:: + + The following definition is not correct and generates an error message: + + .. coqtop:: all + + Fail Fixpoint wrongplus (n m:nat) {struct n} : nat := + match m with + | O => n + | S p => S (wrongplus n p) + end. + + because the declared decreasing argument :g:`n` does not actually + decrease in the recursive call. The function computing the addition over + the second argument should rather be written: + + .. coqtop:: all + + Fixpoint plus (n m:nat) {struct m} : nat := + match m with + | O => n + | S p => S (plus n p) + end. + + .. example:: + + The recursive call may not only be on direct subterms of the recursive + variable :g:`n` but also on a deeper subterm and we can directly write + the function :g:`mod2` which gives the remainder modulo 2 of a natural + number. + + .. coqtop:: all + + Fixpoint mod2 (n:nat) : nat := + match n with + | O => O + | S p => match p with + | O => S O + | S q => mod2 q + end + end. + + + .. cmdv:: Fixpoint @ident @binders {? {struct @ident} } {? : @type } := @term {* with @ident @binders {? : @type } := @term } + + This variant allows defining simultaneously several mutual fixpoints. + It is especially useful when defining functions over mutually defined + inductive types. + + .. example:: + The size of trees and forests can be defined the following way: + + .. coqtop:: all + + Fixpoint tree_size (t:tree) : nat := + match t with + | node a f => S (forest_size f) + end + with forest_size (f:forest) : nat := + match f with + | leaf b => 1 + | cons t f' => (tree_size t + forest_size f') + end. + +.. _cofixpoint: + +Definitions of recursive objects in co-inductive types +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +.. cmd:: CoFixpoint @ident {? @binders } {? : @type } := @term + + This command introduces a method for constructing an infinite object of a + coinductive type. For example, the stream containing all natural numbers can + be introduced applying the following method to the number :g:`O` (see + Section :ref:`coinductive-types` for the definition of :g:`Stream`, :g:`hd` + and :g:`tl`): + + .. coqtop:: all + + CoFixpoint from (n:nat) : Stream := Seq n (from (S n)). + + Oppositely to recursive ones, there is no decreasing argument in a + co-recursive definition. To be admissible, a method of construction must + provide at least one extra constructor of the infinite object for each + iteration. A syntactical guard condition is imposed on co-recursive + definitions in order to ensure this: each recursive call in the + definition must be protected by at least one constructor, and only by + constructors. That is the case in the former definition, where the single + recursive call of :g:`from` is guarded by an application of :g:`Seq`. + On the contrary, the following recursive function does not satisfy the + guard condition: + + .. coqtop:: all + + Fail CoFixpoint filter (p:nat -> bool) (s:Stream) : Stream := + if p (hd s) then Seq (hd s) (filter p (tl s)) else filter p (tl s). + + The elimination of co-recursive definition is done lazily, i.e. the + definition is expanded only when it occurs at the head of an application + which is the argument of a case analysis expression. In any other + context, it is considered as a canonical expression which is completely + evaluated. We can test this using the command :cmd:`Eval`, which computes + the normal forms of a term: + + .. coqtop:: all + + Eval compute in (from 0). + Eval compute in (hd (from 0)). + Eval compute in (tl (from 0)). + + .. cmdv:: CoFixpoint @ident {? @binders } {? : @type } := @term {* with @ident {? @binders } : {? @type } := @term } + + As in the :cmd:`Fixpoint` command, it is possible to introduce a block of + mutually dependent methods. + +.. _Assertions: + +Assertions and proofs +--------------------- + +An assertion states a proposition (or a type) of which the proof (or an +inhabitant of the type) is interactively built using tactics. The interactive +proof mode is described in Chapter :ref:`proofhandling` and the tactics in +Chapter :ref:`Tactics`. The basic assertion command is: + +.. cmd:: Theorem @ident {? @binders } : @type + + After the statement is asserted, Coq needs a proof. Once a proof of + :token:`type` under the assumptions represented by :token:`binders` is given and + validated, the proof is generalized into a proof of :n:`forall @binders, @type` and + the theorem is bound to the name :token:`ident` in the environment. + + .. exn:: The term @term has type @type which should be Set, Prop or Type. + :undocumented: + + .. exn:: @ident already exists. + :name: @ident already exists. (Theorem) + + The name you provided is already defined. You have then to choose + another name. + + .. exn:: Nested proofs are not allowed unless you turn option Nested Proofs Allowed on. + + You are asserting a new statement while already being in proof editing mode. + This feature, called nested proofs, is disabled by default. + To activate it, turn option :opt:`Nested Proofs Allowed` on. + + .. cmdv:: Lemma @ident {? @binders } : @type + Remark @ident {? @binders } : @type + Fact @ident {? @binders } : @type + Corollary @ident {? @binders } : @type + Proposition @ident {? @binders } : @type + :name: Lemma; Remark; Fact; Corollary; Proposition + + These commands are all synonyms of :n:`Theorem @ident {? @binders } : type`. + +.. cmdv:: Theorem @ident {? @binders } : @type {* with @ident {? @binders } : @type} + + This command is useful for theorems that are proved by simultaneous induction + over a mutually inductive assumption, or that assert mutually dependent + statements in some mutual co-inductive type. It is equivalent to + :cmd:`Fixpoint` or :cmd:`CoFixpoint` but using tactics to build the proof of + the statements (or the body of the specification, depending on the point of + view). The inductive or co-inductive types on which the induction or + coinduction has to be done is assumed to be non ambiguous and is guessed by + the system. + + Like in a :cmd:`Fixpoint` or :cmd:`CoFixpoint` definition, the induction hypotheses + have to be used on *structurally smaller* arguments (for a :cmd:`Fixpoint`) or + be *guarded by a constructor* (for a :cmd:`CoFixpoint`). The verification that + recursive proof arguments are correct is done only at the time of registering + the lemma in the environment. To know if the use of induction hypotheses is + correct at some time of the interactive development of a proof, use the + command :cmd:`Guarded`. + + The command can be used also with :cmd:`Lemma`, :cmd:`Remark`, etc. instead of + :cmd:`Theorem`. + +.. cmdv:: Definition @ident {? @binders } : @type + + This allows defining a term of type :token:`type` using the proof editing + mode. It behaves as :cmd:`Theorem` but is intended to be used in conjunction with + :cmd:`Defined` in order to define a constant of which the computational + behavior is relevant. + + The command can be used also with :cmd:`Example` instead of :cmd:`Definition`. + + .. seealso:: :cmd:`Opaque`, :cmd:`Transparent`, :tacn:`unfold`. + +.. cmdv:: Let @ident {? @binders } : @type + + Like :n:`Definition @ident {? @binders } : @type` except that the definition is + turned into a let-in definition generalized over the declarations depending + on it after closing the current section. + +.. cmdv:: Fixpoint @ident @binders : @type {* with @ident @binders : @type} + + This generalizes the syntax of :cmd:`Fixpoint` so that one or more bodies + can be defined interactively using the proof editing mode (when a + body is omitted, its type is mandatory in the syntax). When the block + of proofs is completed, it is intended to be ended by :cmd:`Defined`. + +.. cmdv:: CoFixpoint @ident {? @binders } : @type {* with @ident {? @binders } : @type} + + This generalizes the syntax of :cmd:`CoFixpoint` so that one or more bodies + can be defined interactively using the proof editing mode. + +A proof starts by the keyword :cmd:`Proof`. Then Coq enters the proof editing mode +until the proof is completed. The proof editing mode essentially contains +tactics that are described in chapter :ref:`Tactics`. Besides tactics, there +are commands to manage the proof editing mode. They are described in Chapter +:ref:`proofhandling`. + +When the proof is completed it should be validated and put in the environment +using the keyword :cmd:`Qed`. + +.. note:: + + #. Several statements can be simultaneously asserted provided option + :opt:`Nested Proofs Allowed` was turned on. + + #. Not only other assertions but any vernacular command can be given + while in the process of proving a given assertion. In this case, the + command is understood as if it would have been given before the + statements still to be proved. Nonetheless, this practice is discouraged + and may stop working in future versions. + + #. Proofs ended by :cmd:`Qed` are declared opaque. Their content cannot be + unfolded (see :ref:`performingcomputations`), thus + realizing some form of *proof-irrelevance*. To be able to unfold a + proof, the proof should be ended by :cmd:`Defined`. + + #. :cmd:`Proof` is recommended but can currently be omitted. On the opposite + side, :cmd:`Qed` (or :cmd:`Defined`) is mandatory to validate a proof. + + #. One can also use :cmd:`Admitted` in place of :cmd:`Qed` to turn the + current asserted statement into an axiom and exit the proof editing mode. + +.. [1] + This is similar to the expression “*entry* :math:`\{` sep *entry* + :math:`\}`” in standard BNF, or “*entry* :math:`(` sep *entry* + :math:`)`\ \*” in the syntax of regular expressions. + +.. [2] + Except if the inductive type is empty in which case there is no + equation that can be used to infer the return type. diff --git a/doc/sphinx/practical-tools/coq-commands.rst b/doc/sphinx/practical-tools/coq-commands.rst index 1ff808894a..ad1f0caa60 100644 --- a/doc/sphinx/practical-tools/coq-commands.rst +++ b/doc/sphinx/practical-tools/coq-commands.rst @@ -16,6 +16,8 @@ The options are (basically) the same for the first two commands, and roughly described below. You can also look at the ``man`` pages of ``coqtop`` and ``coqc`` for more details. +.. _interactive-use: + Interactive use (coqtop) ------------------------ @@ -39,10 +41,12 @@ Batch compilation (coqc) The ``coqc`` command takes a name *file* as argument. Then it looks for a vernacular file named *file*.v, and tries to compile it into a -*file*.vo file (See :ref:`TODO-6.5`). Warning: The name *file* should be a -regular |Coq| identifier, as defined in Section :ref:'TODO-1.1'. It should contain -only letters, digits or underscores (_). For instance, ``/bar/foo/toto.v`` is valid, but -``/bar/foo/to-to.v`` is invalid. +*file*.vo file (See :ref:`compiled-files`). + +.. caution:: The name *file* should be a + regular |Coq| identifier, as defined in Section :ref:'TODO-1.1'. It should contain + only letters, digits or underscores (_). For instance, ``/bar/foo/toto.v`` is valid, but + ``/bar/foo/to-to.v`` is invalid. Customization at launch time @@ -51,18 +55,24 @@ Customization at launch time By resource file ~~~~~~~~~~~~~~~~~~~~~~~ -When |Coq| is launched, with either ``coqtop`` or ``coqc``, the resource file -``$XDG_CONFIG_HOME/coq/coqrc.xxx`` is loaded, where ``$XDG_CONFIG_HOME`` +When |Coq| is launched, with either ``coqtop`` or ``coqc``, the +resource file ``$XDG_CONFIG_HOME/coq/coqrc.xxx``, if it exists, will +be implicitly prepended to any document read by Coq, whether it is an +interactive session or a file to compile. Here, ``$XDG_CONFIG_HOME`` is the configuration directory of the user (by default its home -directory ``/.config`` and ``xxx`` is the version number (e.g. 8.8). If +directory ``~/.config``) and ``xxx`` is the version number (e.g. 8.8). If this file is not found, then the file ``$XDG_CONFIG_HOME/coqrc`` is -searched. You can also specify an arbitrary name for the resource file +searched. If not found, it is the file ``~/.coqrc.xxx`` which is searched, +and, if still not found, the file ``~/.coqrc``. If the latter is also +absent, no resource file is loaded. +You can also specify an arbitrary name for the resource file (see option ``-init-file`` below). -This file may contain, for instance, ``Add LoadPath`` commands to add +The resource file may contain, for instance, ``Add LoadPath`` commands to add directories to the load path of |Coq|. It is possible to skip the loading of the resource file with the option ``-q``. +.. _customization-by-environment-variables: By environment variables ~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -70,7 +80,7 @@ By environment variables Load path can be specified to the |Coq| system by setting up ``$COQPATH`` environment variable. It is a list of directories separated by ``:`` (``;`` on Windows). |Coq| will also honor ``$XDG_DATA_HOME`` and -``$XDG_DATA_DIRS`` (see Section :ref:`TODO-2.6.3`). +``$XDG_DATA_DIRS`` (see Section :ref:`libraries-and-filesystem`). Some |Coq| commands call other |Coq| commands. In this case, they look for the commands in directory specified by ``$COQBIN``. If this variable is @@ -84,6 +94,8 @@ list of assignments of the form ``name=``:n:``{*; attr}`` where ANSI escape code. The list of highlight tags can be retrieved with the ``-list-tags`` command-line option of ``coqtop``. +.. _command-line-options: + By command line options ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -91,25 +103,25 @@ The following command-line options are recognized by the commands ``coqc`` and ``coqtop``, unless stated otherwise: :-I *directory*, -include *directory*: Add physical path *directory* - to the OCaml loadpath. See also: :ref:`TODO-2.6.1` and the - command Declare ML Module Section :ref:`TODO-6.5`. + to the OCaml loadpath. See also: :ref:`names-of-libraries` and the + command Declare ML Module Section :ref:`compiled-files`. :-Q *directory* dirpath: Add physical path *directory* to the list of directories where |Coq| looks for a file and bind it to the the logical directory *dirpath*. The subdirectory structure of *directory* is recursively available from |Coq| using absolute names (extending the - dirpath prefix) (see Section :ref:`TODO-2.6.2`).Note that only those + dirpath prefix) (see Section :ref:`qualified-names`).Note that only those subdirectories and files which obey the lexical conventions of what is - an ident (see Section :ref:`TODO-1.1`) are taken into account. Conversely, the + an :n:`@ident` are taken into account. Conversely, the underlying file systems or operating systems may be more restrictive than |Coq|. While Linux’s ext4 file system supports any |Coq| recursive layout (within the limit of 255 bytes per file name), the default on NTFS (Windows) or HFS+ (MacOS X) file systems is on the contrary to disallow two files differing only in the case in the same directory. - See also: Section :ref:`TODO-2.6.1`. + See also: Section :ref:`names-of-libraries`. :-R *directory* dirpath: Do as -Q *directory* dirpath but make the subdirectory structure of *directory* recursively visible so that the recursive contents of physical *directory* is available from |Coq| using - short or partially qualified names. See also: Section :ref:`TODO-2.6.1`. + short or partially qualified names. See also: Section :ref:`names-of-libraries`. :-top dirpath: Set the toplevel module name to dirpath instead of Top. Not valid for `coqc` as the toplevel module name is inferred from the name of the output file. @@ -145,7 +157,7 @@ and ``coqtop``, unless stated otherwise: -compile-verbose. :-w (all|none|w₁,…,wₙ): Configure the display of warnings. This option expects all, none or a comma-separated list of warning names or - categories (see Section :ref:`TODO-6.9.3`). + categories (see Section :ref:`controlling-display`). :-color (on|off|auto): Enable or not the coloring of output of `coqtop`. Default is auto, meaning that `coqtop` dynamically decides, depending on whether the output channel supports ANSI escape sequences. @@ -164,13 +176,13 @@ and ``coqtop``, unless stated otherwise: Coq's auto-generated name scheme with names of the form *ident0*, *ident1*, etc. The command ``Set Mangle Names`` turns the behavior on in a document, and ``Set Mangle Names Prefix "ident"`` changes the used prefix. This feature - s intended to be used as a linter for developments that want to be robust to + is intended to be used as a linter for developments that want to be robust to changes in the auto-generated name scheme. The options are provided to facilitate tracking down problems. :-compat *version*: Attempt to maintain some backward-compatibility with a previous version. :-dump-glob *file*: Dump references for global names in file *file* - (to be used by coqdoc, see :ref:`TODO-15.4`). By default, if *file.v* is being + (to be used by coqdoc, see :ref:`coqdoc`). By default, if *file.v* is being compiled, *file.glob* is used. :-no-glob: Disable the dumping of references for global names. :-image *file*: Set the binary image to be used by `coqc` to be *file* diff --git a/doc/sphinx/practical-tools/coqide.rst b/doc/sphinx/practical-tools/coqide.rst index 1fcfc665be..f9903e6104 100644 --- a/doc/sphinx/practical-tools/coqide.rst +++ b/doc/sphinx/practical-tools/coqide.rst @@ -10,7 +10,7 @@ used as a user-friendly replacement to `coqtop`. Its main purpose is to allow the user to navigate forward and backward into a Coq vernacular file, executing corresponding commands or undoing them respectively. -CoqIDE is run by typing the command `coqide` on the command line. +|CoqIDE| is run by typing the command `coqide` on the command line. Without argument, the main screen is displayed with an “unnamed buffer”, and with a file name as argument, another buffer displaying the contents of that file. Additionally, `coqide` accepts the same @@ -43,7 +43,7 @@ is the one where Coq commands are currently executed. Buffers may be edited as in any text editor, and classical basic editing commands (Copy/Paste, …) are available in the *Edit* menu. -CoqIDE offers only basic editing commands, so if you need more complex +|CoqIDE| offers only basic editing commands, so if you need more complex editing commands, you may launch your favorite text editor on the current buffer, using the *Edit/External Editor* menu. @@ -75,7 +75,7 @@ There are two additional buttons for navigation within the running buffer. The "down" button with a line goes directly to the end; the "up" button with a line goes back to the beginning. The handling of errors when using the go-to-the-end button depends on whether |Coq| is running in asynchronous mode or not (see -Chapter :ref:`Asyncprocessing`). If it is not running in that mode, execution +Chapter :ref:`asynchronousandparallelproofprocessing`). If it is not running in that mode, execution stops as soon as an error is found. Otherwise, execution continues, and the error is marked with an underline in the error foreground color, with a background in the error background color (pink by default). The same @@ -86,14 +86,14 @@ If you ever try to execute a command which happens to run during a long time, and would like to abort it before its termination, you may use the interrupt button (the white cross on a red circle). -There are other buttons on the CoqIDE toolbar: a button to save the running +There are other buttons on the |CoqIDE| toolbar: a button to save the running buffer; a button to close the current buffer (an "X"); buttons to switch among buffers (left and right arrows); an "information" button; and a "gears" button. -The "information" button is described in Section :ref:`sec:trytactics`. +The "information" button is described in Section :ref:`try-tactics-automatically`. The "gears" button submits proof terms to the |Coq| kernel for type-checking. -When |Coq| uses asynchronous processing (see Chapter :ref:`Asyncprocessing`), +When |Coq| uses asynchronous processing (see Chapter :ref:`asynchronousandparallelproofprocessing`), proofs may have been completed without kernel-checking of generated proof terms. The presence of unchecked proof terms is indicated by ``Qed`` statements that have a subdued *being-processed* color (light blue by default), rather than the @@ -150,18 +150,16 @@ arguments. Queries ------------ -.. _coqide_queryselected: - .. image:: ../_static/coqide-queries.png :alt: |CoqIDE| queries We call *query* any vernacular command that does not change the current state, such as ``Check``, ``Search``, etc. To run such commands interactively, without -writing them in scripts, CoqIDE offers a *query pane*. The query pane can be +writing them in scripts, |CoqIDE| offers a *query pane*. The query pane can be displayed on demand by using the ``View`` menu, or using the shortcut ``F1``. Queries can also be performed by selecting a particular phrase, then choosing an item from the ``Queries`` menu. The response then appears in the message window. -Figure :ref:`fig:queryselected` shows the result after selecting of the phrase +The image above shows the result after selecting of the phrase ``Nat.mul`` in the script window, and choosing ``Print`` from the ``Queries`` menu. @@ -221,7 +219,7 @@ still edit this configuration file by hand, but this is more involved. Using Unicode symbols -------------------------- -CoqIDE is based on GTK+ and inherits from it support for Unicode in +|CoqIDE| is based on GTK+ and inherits from it support for Unicode in its text windows. Consequently a large set of symbols is available for notations. diff --git a/doc/sphinx/practical-tools/utilities.rst b/doc/sphinx/practical-tools/utilities.rst new file mode 100644 index 0000000000..59a88771a0 --- /dev/null +++ b/doc/sphinx/practical-tools/utilities.rst @@ -0,0 +1,1008 @@ +.. include:: ../replaces.rst + +.. _utilities: + +--------------------- + Utilities +--------------------- + +The distribution provides utilities to simplify some tedious works +beside proof development, tactics writing or documentation. + + +Using Coq as a library +---------------------- + +In previous versions, ``coqmktop`` was used to build custom +toplevels - for example for better debugging or custom static +linking. Nowadays, the preferred method is to use ``ocamlfind``. + +The most basic custom toplevel is built using: + +:: + + % ocamlfind ocamlopt -thread -rectypes -linkall -linkpkg \ + -package coq.toplevel \ + toplevel/coqtop\_bin.ml -o my\_toplevel.native + + +For example, to statically link |L_tac|, you can just do: + +:: + + % ocamlfind ocamlopt -thread -rectypes -linkall -linkpkg \ + -package coq.toplevel -package coq.ltac \ + toplevel/coqtop\_bin.ml -o my\_toplevel.native + +and similarly for other plugins. + + +Building a |Coq| project with coq_makefile +------------------------------------------ + +The majority of |Coq| projects are very similar: a collection of ``.v`` +files and eventually some ``.ml`` ones (a |Coq| plugin). The main piece of +metadata needed in order to build the project are the command line +options to ``coqc`` (e.g. ``-R``, ``-I``, see also: Section +:ref:`command-line-options`). Collecting the list of files and options is the job +of the ``_CoqProject`` file. + +A simple example of a ``_CoqProject`` file follows: + +:: + + -R theories/ MyCode + theories/foo.v + theories/bar.v + -I src/ + src/baz.ml4 + src/bazaux.ml + src/qux_plugin.mlpack + + +Currently, both |CoqIDE| and Proof-General (version ≥ ``4.3pre``) +understand ``_CoqProject`` files and invoke |Coq| with the desired options. + +The ``coq_makefile`` utility can be used to set up a build infrastructure +for the |Coq| project based on makefiles. The recommended way of +invoking ``coq_makefile`` is the following one: + +:: + + coq_makefile -f _CoqProject -o CoqMakefile + + +Such command generates the following files: + +CoqMakefile + is a generic makefile for ``GNU Make`` that provides + targets to build the project (both ``.v`` and ``.ml*`` files), to install it + system-wide in the ``coq-contrib`` directory (i.e. where |Coq| is installed) + as well as to invoke coqdoc to generate HTML documentation. + +CoqMakefile.conf + contains make variables assignments that reflect + the contents of the ``_CoqProject`` file as well as the path relevant to + |Coq|. + + +An optional file ``CoqMakefile.local`` can be provided by the user in order to +extend ``CoqMakefile``. In particular one can declare custom actions to be +performed before or after the build process. Similarly one can customize the +install target or even provide new targets. Extension points are documented in +paragraph :ref:`coqmakefilelocal`. + +The extensions of the files listed in ``_CoqProject`` is used in order to +decide how to build them. In particular: + + ++ |Coq| files must use the ``.v`` extension ++ |OCaml| files must use the ``.ml`` or ``.mli`` extension ++ |OCaml| files that require pre processing for syntax + extensions (like ``VERNAC EXTEND``) must use the ``.ml4`` extension ++ In order to generate a plugin one has to list all |OCaml| + modules (i.e. ``Baz`` for ``baz.ml``) in a ``.mlpack`` file (or ``.mllib`` + file). + + +The use of ``.mlpack`` files has to be preferred over ``.mllib`` files, +since it results in a “packed” plugin: All auxiliary modules (as +``Baz`` and ``Bazaux``) are hidden inside the plugin’s “name space” +(``Qux_plugin``). This reduces the chances of begin unable to load two +distinct plugins because of a clash in their auxiliary module names. + +.. _coqmakefilelocal: + +CoqMakefile.local +~~~~~~~~~~~~~~~~~ + +The optional file ``CoqMakefile.local`` is included by the generated +file ``CoqMakefile``. It can contain two kinds of directives. + +**Variable assignment** + +The variable must belong to the variables listed in the ``Parameters`` +section of the generated makefile. +Here we describe only few of them. + +:CAMLPKGS: + can be used to specify third party findlib packages, and is + passed to the OCaml compiler on building or linking of modules. Eg: + ``-package yojson``. +:CAMLFLAGS: + can be used to specify additional flags to the |OCaml| + compiler, like ``-bin-annot`` or ``-w``.... +:COQC, COQDEP, COQDOC: + can be set in order to use alternative binaries + (e.g. wrappers) +:COQ_SRC_SUBDIRS: + can be extended by including other paths in which ``*.cm*`` files + are searched. For example ``COQ_SRC_SUBDIRS+=user-contrib/Unicoq`` + lets you build a plugin containing OCaml code that depends on the + OCaml code of ``Unicoq``. + +**Rule extension** + +The following makefile rules can be extended. + +.. example:: + + :: + + pre-all:: + echo "This line is print before making the all target" + install-extra:: + cp ThisExtraFile /there/it/goes + +``pre-all::`` + run before the ``all`` target. One can use this to configure + the project, or initialize sub modules or check dependencies are met. + +``post-all::`` + run after the ``all`` target. One can use this to run a test + suite, or compile extracted code. + +``install-extra::`` + run after ``install``. One can use this to install extra files. + +``install-doc::`` + One can use this to install extra doc. + +``uninstall::`` + \ + +``uninstall-doc::`` + \ + +``clean::`` + \ + +``cleanall::`` + \ + +``archclean::`` + \ + +``merlin-hook::`` + One can append lines to the generated ``.merlin`` file extending this + target. + +Timing targets and performance testing +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The generated ``Makefile`` supports the generation of two kinds of timing +data: per-file build-times, and per-line times for an individual file. + +The following targets and Makefile variables allow collection of per- +file timing data: + + ++ ``TIMED=1`` + passing this variable will cause ``make`` to emit a line + describing the user-space build-time and peak memory usage for each + file built. + + .. note:: + On ``Mac OS``, this works best if you’ve installed ``gnu-time``. + + .. example:: + For example, the output of ``make TIMED=1`` may look like + this: + + :: + + COQDEP Fast.v + COQDEP Slow.v + COQC Slow.v + Slow (user: 0.34 mem: 395448 ko) + COQC Fast.v + Fast (user: 0.01 mem: 45184 ko) + ++ ``pretty-timed`` + this target stores the output of ``make TIMED=1`` into + ``time-of-build.log``, and displays a table of the times, sorted from + slowest to fastest, which is also stored in ``time-of-build-pretty.log``. + If you want to construct the ``log`` for targets other than the default + one, you can pass them via the variable ``TGTS``, e.g., ``make pretty-timed + TGTS="a.vo b.vo"``. + + .. :: + This target requires ``python`` to build the table. + + .. note:: + This target will *append* to the timing log; if you want a + fresh start, you must remove the ``filetime-of-build.log`` or + ``run make cleanall``. + + .. example:: + + For example, the output of ``make pretty-timed`` may look like this: + + :: + + COQDEP Fast.v + COQDEP Slow.v + COQC Slow.v + Slow (user: 0.36 mem: 393912 ko) + COQC Fast.v + Fast (user: 0.05 mem: 45992 ko) + Time | File Name + -------------------- + 0m00.41s | Total + -------------------- + 0m00.36s | Slow + 0m00.05s | Fast + + ++ ``print-pretty-timed-diff`` + this target builds a table of timing + changes between two compilations; run ``make make-pretty-timed-before`` to + build the log of the “before” times, and run ``make make-pretty-timed- + after`` to build the log of the “after” times. The table is printed on + the command line, and stored in ``time-of-build-both.log``. This target is + most useful for profiling the difference between two commits to a + repo. + + .. note:: + This target requires ``python`` to build the table. + + .. note:: + The ``make-pretty-timed-before`` and ``make-pretty-timed-after`` targets will + *append* to the timing log; if you want a fresh start, you must remove + the files ``time-of-build-before.log`` and ``time-of-build-after.log`` or run + ``make cleanall`` *before* building either the “before” or “after” + targets. + + .. note:: + The table will be sorted first by absolute time + differences rounded towards zero to a whole-number of seconds, then by + times in the “after” column, and finally lexicographically by file + name. This will put the biggest changes in either direction first, and + will prefer sorting by build-time over subsecond changes in build time + (which are frequently noise); lexicographic sorting forces an order on + files which take effectively no time to compile. + + .. example:: + For example, the output table from + ``make print-pretty-timed-diff`` may look like this: + + :: + + After | File Name | Before || Change | % Change + -------------------------------------------------------- + 0m00.39s | Total | 0m00.35s || +0m00.03s | +11.42% + -------------------------------------------------------- + 0m00.37s | Slow | 0m00.01s || +0m00.36s | +3600.00% + 0m00.02s | Fast | 0m00.34s || -0m00.32s | -94.11% + + +The following targets and ``Makefile`` variables allow collection of per- +line timing data: + + ++ ``TIMING=1`` + passing this variable will cause ``make`` to use ``coqc -time`` to + write to a ``.v.timing`` file for each ``.v`` file compiled, which contains + line-by-line timing information. + + .. example:: + For example, running ``make all TIMING=1`` may result in a file like this: + + :: + + Chars 0 - 26 [Require~Coq.ZArith.BinInt.] 0.157 secs (0.128u,0.028s) + Chars 27 - 68 [Declare~Reduction~comp~:=~vm_c...] 0. secs (0.u,0.s) + Chars 69 - 162 [Definition~foo0~:=~Eval~comp~i...] 0.153 secs (0.136u,0.019s) + Chars 163 - 208 [Definition~foo1~:=~Eval~comp~i...] 0.239 secs (0.236u,0.s) + ++ ``print-pretty-single-time-diff`` + :: + print-pretty-single-time-diff BEFORE=path/to/file.v.before-timing AFTER=path/to/file.v.after-timing + + this target will make a sorted table of the per-line timing differences + between the timing logs in the ``BEFORE`` and ``AFTER`` files, display it, and + save it to the file specified by the ``TIME_OF_PRETTY_BUILD_FILE`` variable, + which defaults to ``time-of-build-pretty.log``. + To generate the ``.v.before-timing`` or ``.v.after-timing`` files, you should + pass ``TIMING=before`` or ``TIMING=after`` rather than ``TIMING=1``. + + .. note:: + The sorting used here is the same as in the ``print-pretty-timed -diff`` target. + + .. note:: + This target requires python to build the table. + + .. example:: + For example, running ``print-pretty-single-time-diff`` might give a table like this: + + :: + + After | Code | Before || Change | % Change + --------------------------------------------------------------------------------------------------- + 0m00.50s | Total | 0m04.17s || -0m03.66s | -87.96% + --------------------------------------------------------------------------------------------------- + 0m00.145s | Chars 069 - 162 [Definition~foo0~:=~Eval~comp~i...] | 0m00.192s || -0m00.04s | -24.47% + 0m00.126s | Chars 000 - 026 [Require~Coq.ZArith.BinInt.] | 0m00.143s || -0m00.01s | -11.88% + N/A | Chars 027 - 068 [Declare~Reduction~comp~:=~nati...] | 0m00.s || +0m00.00s | N/A + 0m00.s | Chars 027 - 068 [Declare~Reduction~comp~:=~vm_c...] | N/A || +0m00.00s | N/A + 0m00.231s | Chars 163 - 208 [Definition~foo1~:=~Eval~comp~i...] | 0m03.836s || -0m03.60s | -93.97% + + ++ ``all.timing.diff``, ``path/to/file.v.timing.diff`` + The ``path/to/file.v.timing.diff`` target will make a ``.v.timing.diff`` file for + the corresponding ``.v`` file, with a table as would be generated by + the ``print-pretty-single-time-diff`` target; it depends on having already + made the corresponding ``.v.before-timing`` and ``.v.after-timing`` files, + which can be made by passing ``TIMING=before`` and ``TIMING=after``. + The ``all.timing.diff`` target will make such timing difference files for + all of the ``.v`` files that the ``Makefile`` knows about. It will fail if + some ``.v.before-timing`` or ``.v.after-timing`` files don’t exist. + + .. note:: + This target requires python to build the table. + + +Reusing/extending the generated Makefile +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Including the generated makefile with an include directive is +discouraged. The contents of this file, including variable names and +status of rules shall change in the future. Users are advised to +include ``Makefile.conf`` or call a target of the generated Makefile as in +``make -f Makefile target`` from another Makefile. + +One way to get access to all targets of the generated ``CoqMakefile`` is to +have a generic target for invoking unknown targets. + +.. example:: + + :: + + # KNOWNTARGETS will not be passed along to CoqMakefile + KNOWNTARGETS := CoqMakefile extra-stuff extra-stuff2 + # KNOWNFILES will not get implicit targets from the final rule, and so + # depending on them won't invoke the submake + # Warning: These files get declared as PHONY, so any targets depending + # on them always get rebuilt + KNOWNFILES := Makefile _CoqProject + + .DEFAULT_GOAL := invoke-coqmakefile + + CoqMakefile: Makefile _CoqProject + $(COQBIN)coq_makefile -f _CoqProject -o CoqMakefile + + invoke-coqmakefile: CoqMakefile + $(MAKE) --no-print-directory -f CoqMakefile $(filter-out $(KNOWNTARGETS),$(MAKECMDGOALS)) + + .PHONY: invoke-coqmakefile $(KNOWNFILES) + + #################################################################### + ## Your targets here ## + #################################################################### + + # This should be the last rule, to handle any targets not declared above + %: invoke-coqmakefile + @true + + + +Building a subset of the targets with ``-j`` +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +To build, say, two targets foo.vo and bar.vo in parallel one can use +``make only TGTS="foo.vo bar.vo" -j``. + +.. note:: + + ``make foo.vo bar.vo -j`` has a different meaning for the make + utility, in particular it may build a shared prerequisite twice. + + +.. note:: + + For users of coq_makefile with version < 8.7 + + + Support for “sub-directory” is deprecated. To perform actions before + or after the build (like invoking ``make`` on a subdirectory) one can hook + in pre-all and post-all extension points. + + ``-extra-phony`` and ``-extra`` are deprecated. To provide additional target + (``.PHONY`` or not) please use ``CoqMakefile.local``. + + + +Modules dependencies +-------------------- + +In order to compute modules dependencies (so to use ``make``), |Coq| comes +with an appropriate tool, ``coqdep``. + +``coqdep`` computes inter-module dependencies for |Coq| and |OCaml| +programs, and prints the dependencies on the standard output in a +format readable by make. When a directory is given as argument, it is +recursively looked at. + +Dependencies of |Coq| modules are computed by looking at ``Require`` +commands (``Require``, ``Require Export``, ``Require Import``), but also at the +command ``Declare ML Module``. + +Dependencies of |OCaml| modules are computed by looking at +`open` commands and the dot notation *module.value*. However, this is +done approximately and you are advised to use ``ocamldep`` instead for the +|OCaml| modules dependencies. + +See the man page of ``coqdep`` for more details and options. + +The build infrastructure generated by ``coq_makefile`` uses ``coqdep`` to +automatically compute the dependencies among the files part of the +project. + + +.. _coqdoc: + +Documenting |Coq| files with coqdoc +----------------------------------- + +coqdoc is a documentation tool for the proof assistant |Coq|, similar to +``javadoc`` or ``ocamldoc``. The task of coqdoc is + + +#. to produce a nice |Latex| and/or HTML document from the |Coq| + sources, readable for a human and not only for the proof assistant; +#. to help the user navigating in his own (or third-party) sources. + + + +Principles +~~~~~~~~~~ + +Documentation is inserted into |Coq| files as *special comments*. Thus +your files will compile as usual, whether you use coqdoc or not. coqdoc +presupposes that the given |Coq| files are well-formed (at least +lexically). Documentation starts with ``(**``, followed by a space, and +ends with the pending ``*)``. The documentation format is inspired by Todd +A. Coram’s *Almost Free Text (AFT)* tool: it is mainly ``ASCII`` text with +some syntax-light controls, described below. coqdoc is robust: it +shouldn’t fail, whatever the input is. But remember: “garbage in, +garbage out”. + + +|Coq| material inside documentation. +++++++++++++++++++++++++++++++++++++ + +|Coq| material is quoted between the delimiters ``[`` and ``]``. Square brackets +may be nested, the inner ones being understood as being part of the +quoted code (thus you can quote a term like ``fun x => u`` by writing ``[fun +x => u]``). Inside quotations, the code is pretty-printed in the same +way as it is in code parts. + +Pre-formatted vernacular is enclosed by ``[[`` and ``]]``. The former must be +followed by a newline and the latter must follow a newline. + + +Pretty-printing. +++++++++++++++++ + +coqdoc uses different faces for identifiers and keywords. The pretty- +printing of |Coq| tokens (identifiers or symbols) can be controlled +using one of the following commands: + +:: + + + (** printing *token* %...LATEX...% #...html...# *) + + +or + +:: + + + (** printing *token* $...LATEX math...$ #...html...# *) + + +It gives the |Latex| and HTML texts to be produced for the given |Coq| +token. One of the |Latex| or HTML text may be omitted, causing the +default pretty-printing to be used for this token. + +The printing for one token can be removed with + +:: + + + (** remove printing *token* *) + + +Initially, the pretty-printing table contains the following mapping: + +==== === ==== ===== === ==== ==== === +`->` → `<-` ← `*` × +`<=` ≤ `>=` ≥ `=>` ⇒ +`<>` ≠ `<->` ↔ `|-` ⊢ +`\/` ∨ `/\\` ∧ `~` ¬ +==== === ==== ===== === ==== ==== === + +Any of these can be overwritten or suppressed using the printing +commands. + +.. note:: + + The recognition of tokens is done by a (``ocaml``) lex + automaton and thus applies the longest-match rule. For instance, `->~` + is recognized as a single token, where |Coq| sees two tokens. It is the + responsibility of the user to insert space between tokens *or* to give + pretty-printing rules for the possible combinations, e.g. + + :: + + (** printing ->~ %\ensuremath{\rightarrow\lnot}% *) + + + +Sections +++++++++ + +Sections are introduced by 1 to 4 leading stars (i.e. at the beginning +of the line) followed by a space. One star is a section, two stars a +sub-section, etc. The section title is given on the remaining of the +line. + +.. example:: + + :: + + (** * Well-founded relations + + In this section, we introduce... *) + + +Lists. +++++++ + +List items are introduced by a leading dash. coqdoc uses whitespace to +determine the depth of a new list item and which text belongs in which +list items. A list ends when a line of text starts at or before the +level of indenting of the list’s dash. A list item’s dash must always +be the first non-space character on its line (so, in particular, a +list can not begin on the first line of a comment - start it on the +second line instead). + +.. example:: + + :: + + We go by induction on [n]: + - If [n] is 0... + - If [n] is [S n'] we require... + + two paragraphs of reasoning, and two subcases: + + - In the first case... + - In the second case... + + So the theorem holds. + + + +Rules. +++++++ + +More than 4 leading dashes produce a horizontal rule. + + +Emphasis. ++++++++++ + +Text can be italicized by placing it in underscores. A non-identifier +character must precede the leading underscore and follow the trailing +underscore, so that uses of underscores in names aren’t mistaken for +emphasis. Usually, these are spaces or punctuation. + +:: + + This sentence contains some _emphasized text_. + + + +Escaping to |Latex| and HTML. ++++++++++++++++++++++++++++++++ + +Pure |Latex| or HTML material can be inserted using the following +escape sequences: + + ++ ``$...LATEX stuff...$`` inserts some |Latex| material in math mode. + Simply discarded in HTML output. ++ ``%...LATEX stuff...%`` inserts some |Latex| material. Simply + discarded in HTML output. ++ ``#...HTML stuff...#`` inserts some HTML material. Simply discarded in + |Latex| output. + +.. note:: + to simply output the characters ``$``, ``%`` and ``#`` and escaping + their escaping role, these characters must be doubled. + + +Verbatim +++++++++ + +Verbatim material is introduced by a leading ``<<`` and closed by ``>>`` +at the beginning of a line. + +.. example:: + + :: + + Here is the corresponding caml code: + << + let rec fact n = + if n <= 1 then 1 else n * fact (n-1) + >> + + + +Hyperlinks +++++++++++ + +Hyperlinks can be inserted into the HTML output, so that any +identifier is linked to the place of its definition. + +``coqc file.v`` automatically dumps localization information in +``file.glob`` or appends it to a file specified using option ``--dump-glob +file``. Take care of erasing this global file, if any, when starting +the whole compilation process. + +Then invoke coqdoc or ``coqdoc --glob-from file`` to tell coqdoc to look +for name resolutions into the file ``file`` (it will look in ``file.glob`` +by default). + +Identifiers from the |Coq| standard library are linked to the Coq web +site at `<http://coq.inria.fr/library/>`_. This behavior can be changed +using command line options ``--no-externals`` and ``--coqlib``; see below. + + +Hiding / Showing parts of the source. ++++++++++++++++++++++++++++++++++++++ + +Some parts of the source can be hidden using command line options ``-g`` +and ``-l`` (see below), or using such comments: + +:: + + + (* begin hide *) + *some Coq material* + (* end hide *) + + +Conversely, some parts of the source which would be hidden can be +shown using such comments: + +:: + + + (* begin show *) + *some Coq material* + (* end show *) + + +The latter cannot be used around some inner parts of a proof, but can +be used around a whole proof. + + +Usage +~~~~~ + +coqdoc is invoked on a shell command line as follows: +``coqdoc <options and files>``. +Any command line argument which is not an option is considered to be a +file (even if it starts with a ``-``). |Coq| files are identified by the +suffixes ``.v`` and ``.g`` and |Latex| files by the suffix ``.tex``. + + +:HTML output: This is the default output. One HTML file is created for + each |Coq| file given on the command line, together with a file + ``index.html`` (unless ``option-no-index is passed``). The HTML pages use a + style sheet named ``style.css``. Such a file is distributed with coqdoc. +:|Latex| output: A single |Latex| file is created, on standard + output. It can be redirected to a file with option ``-o``. The order of + files on the command line is kept in the final document. |Latex| + files given on the command line are copied ‘as is’ in the final + document . DVI and PostScript can be produced directly with the + options ``-dvi`` and ``-ps`` respectively. +:TEXmacs output: To translate the input files to TEXmacs format, + to be used by the TEXmacs |Coq| interface. + + + +Command line options +++++++++++++++++++++ + + +**Overall options** + + + :--HTML: Select a HTML output. + :--|Latex|: Select a |Latex| output. + :--dvi: Select a DVI output. + :--ps: Select a PostScript output. + :--texmacs: Select a TEXmacs output. + :--stdout: Write output to stdout. + :-o file, --output file: Redirect the output into the file ‘file’ + (meaningless with ``-html``). + :-d dir, --directory dir: Output files into directory ‘dir’ instead of + current directory (option ``-d`` does not change the filename specified + with option ``-o``, if any). + :--body-only: Suppress the header and trailer of the final document. + Thus, you can insert the resulting document into a larger one. + :-p string, --preamble string: Insert some material in the |Latex| + preamble, right before ``\begin{document}`` (meaningless with ``-html``). + :--vernac-file file,--tex-file file: Considers the file ‘file’ + respectively as a ``.v`` (or ``.g``) file or a ``.tex`` file. + :--files-from file: Read file names to process in file ‘file’ as if + they were given on the command line. Useful for program sources split + up into several directories. + :-q, --quiet: Be quiet. Do not print anything except errors. + :-h, --help: Give a short summary of the options and exit. + :-v, --version: Print the version and exit. + + + +**Index options** + + Default behavior is to build an index, for the HTML output only, + into ``index.html``. + + :--no-index: Do not output the index. + :--multi-index: Generate one page for each category and each letter in + the index, together with a top page ``index.html``. + :--index string: Make the filename of the index string instead of + “index”. Useful since “index.html” is special. + + + +**Table of contents option** + + :-toc, --table-of-contents: Insert a table of contents. For a |Latex| + output, it inserts a ``\tableofcontents`` at the beginning of the + document. For a HTML output, it builds a table of contents into + ``toc.html``. + :--toc-depth int: Only include headers up to depth ``int`` in the table of + contents. + + +**Hyperlinks options** + + :--glob-from file: Make references using |Coq| globalizations from file + file. (Such globalizations are obtained with Coq option ``-dump-glob``). + :--no-externals: Do not insert links to the |Coq| standard library. + :--external url coqdir: Use given URL for linking references whose + name starts with prefix ``coqdir``. + :--coqlib url: Set base URL for the Coq standard library (default is + `<http://coq.inria.fr/library/>`_). This is equivalent to ``--external url + Coq``. + :-R dir coqdir: Map physical directory dir to |Coq| logical + directory ``coqdir`` (similarly to |Coq| option ``-R``). + + .. note:: + + option ``-R`` only has + effect on the files *following* it on the command line, so you will + probably need to put this option first. + + +**Title options** + + :-s , --short: Do not insert titles for the files. The default + behavior is to insert a title like “Library Foo” for each file. + :--lib-name string: Print “string Foo” instead of “Library Foo” in + titles. For example “Chapter” and “Module” are reasonable choices. + :--no-lib-name: Print just “Foo” instead of “Library Foo” in titles. + :--lib-subtitles: Look for library subtitles. When enabled, the + beginning of each file is checked for a comment of the form: + + :: + + (** * ModuleName : text *) + + where ``ModuleName`` must be the name of the file. If it is present, the + text is used as a subtitle for the module in appropriate places. + :-t string, --title string: Set the document title. + + +**Contents options** + + :-g, --gallina: Do not print proofs. + :-l, --light: Light mode. Suppress proofs (as with ``-g``) and the following commands: + + + [Recursive] Tactic Definition + + Hint / Hints + + Require + + Transparent / Opaque + + Implicit Argument / Implicits + + Section / Variable / Hypothesis / End + + + + The behavior of options ``-g`` and ``-l`` can be locally overridden using the + ``(* begin show *) … (* end show *)`` environment (see above). + + There are a few options to drive the parsing of comments: + + :--parse-comments: Parses regular comments delimited by ``(*`` and ``*)`` as + well. They are typeset inline. + :--plain-comments: Do not interpret comments, simply copy them as + plain-text. + :--interpolate: Use the globalization information to typeset + identifiers appearing in |Coq| escapings inside comments. + +**Language options** + + + Default behavior is to assume ASCII 7 bits input files. + + :-latin1, --latin1: Select ISO-8859-1 input files. It is equivalent to + --inputenc latin1 --charset iso-8859-1. + :-utf8, --utf8: Set --inputenc utf8x for |Latex| output and--charset + utf-8 for HTML output. Also use Unicode replacements for a couple of + standard plain ASCII notations such as → for ``->`` and ∀ for ``forall``. |Latex| + UTF-8 support can be found + at `<http://www.ctan.org/pkg/unicode>`_. For the interpretation of Unicode + characters by |Latex|, extra packages which coqdoc does not provide + by default might be required, such as textgreek for some Greek letters + or ``stmaryrd`` for some mathematical symbols. If a Unicode character is + missing an interpretation in the utf8x input encoding, add + ``\DeclareUnicodeCharacter{code}{LATEX-interpretation}``. Packages + and declarations can be added with option ``-p``. + :--inputenc string: Give a |Latex| input encoding, as an option to |Latex| + package ``inputenc``. + :--charset string: Specify the HTML character set, to be inserted in + the HTML header. + + + +The coqdoc |Latex| style file +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +In case you choose to produce a document without the default |Latex| +preamble (by using option ``--no-preamble``), then you must insert into +your own preamble the command + +:: + + \usepackage{coqdoc} + +The package optionally takes the argument ``[color]`` to typeset +identifiers with colors (this requires the ``xcolor`` package). + +Then you may alter the rendering of the document by redefining some +macros: + +:coqdockw, coqdocid, …: The one-argument macros for typesetting + keywords and identifiers. Defaults are sans-serif for keywords and + italic for identifiers.For example, if you would like a slanted font + for keywords, you may insert + + :: + + \renewcommand{\coqdockw}[1]{\textsl{#1}} + + + anywhere between ``\usepackage{coqdoc}`` and ``\begin{document}``. + + +:coqdocmodule: + One-argument macro for typesetting the title of a ``.v`` + file. Default is + + :: + + \newcommand{\coqdocmodule}[1]{\section*{Module #1}} + + and you may redefine it using ``\renewcommand``. + +Embedded Coq phrases inside |Latex| documents +--------------------------------------------- + +When writing a documentation about a proof development, one may want +to insert |Coq| phrases inside a |Latex| document, possibly together +with the corresponding answers of the system. We provide a mechanical +way to process such |Coq| phrases embedded in |Latex| files: the ``coq-tex`` +filter. This filter extracts |Coq| phrases embedded in |Latex| files, +evaluates them, and insert the outcome of the evaluation after each +phrase. + +Starting with a file ``file.tex`` containing |Coq| phrases, the ``coq-tex`` +filter produces a file named ``file.v.tex`` with the Coq outcome. + +There are options to produce the |Coq| parts in smaller font, italic, +between horizontal rules, etc. See the man page of ``coq-tex`` for more +details. + +|Coq| and GNU Emacs +----------------------- + + +The |Coq| Emacs mode +~~~~~~~~~~~~~~~~~~~~~~~~~ + +|Coq| comes with a Major mode for GNU Emacs, ``gallina.el``. This mode +provides syntax highlighting and also a rudimentary indentation +facility in the style of the ``Caml`` GNU Emacs mode. + +Add the following lines to your ``.emacs`` file: + +:: + + (setq auto-mode-alist (cons '("\\.v$" . coq-mode) auto-mode-alist)) + (autoload 'coq-mode "gallina" "Major mode for editing Coq vernacular." t) + + +The |Coq| major mode is triggered by visiting a file with extension ``.v``, +or manually with the command ``M-x coq-mode``. It gives you the correct +syntax table for the |Coq| language, and also a rudimentary indentation +facility: + + ++ pressing ``Tab`` at the beginning of a line indents the line like the + line above; ++ extra tabulations increase the indentation level (by 2 spaces by default); ++ ``M-Tab`` decreases the indentation level. + + +An inferior mode to run |Coq| under Emacs, by Marco Maggesi, is also +included in the distribution, in file ``inferior-coq.el``. Instructions to +use it are contained in this file. + + +Proof-General +~~~~~~~~~~~~~ + +Proof-General is a generic interface for proof assistants based on +Emacs. The main idea is that the |Coq| commands you are editing are sent +to a |Coq| toplevel running behind Emacs and the answers of the system +automatically inserted into other Emacs buffers. Thus you don’t need +to copy-paste the |Coq| material from your files to the |Coq| toplevel or +conversely from the |Coq| toplevel to some files. + +Proof-General is developed and distributed independently of the system +|Coq|. It is freely available at `<https://proofgeneral.github.io/>`_. + + +Module specification +-------------------- + +Given a |Coq| vernacular file, the gallina filter extracts its +specification (inductive types declarations, definitions, type of +lemmas and theorems), removing the proofs parts of the file. The |Coq| +file ``file.v`` gives birth to the specification file ``file.g`` (where +the suffix ``.g`` stands for |Gallina|). + +See the man page of ``gallina`` for more details and options. + + +Man pages +--------- + +There are man pages for the commands ``coqdep``, ``gallina`` and ``coq-tex``. Man +pages are installed at installation time (see installation +instructions in file ``INSTALL``, step 6). diff --git a/doc/sphinx/proof-engine/detailed-tactic-examples.rst b/doc/sphinx/proof-engine/detailed-tactic-examples.rst index 932f967881..84810ddba5 100644 --- a/doc/sphinx/proof-engine/detailed-tactic-examples.rst +++ b/doc/sphinx/proof-engine/detailed-tactic-examples.rst @@ -6,6 +6,8 @@ Detailed examples of tactics This chapter presents detailed examples of certain tactics, to illustrate their behavior. +.. _dependent-induction: + dependent induction ------------------- @@ -316,7 +318,7 @@ explicit proof terms: This concludes our example. -See also: The ``induction`` :ref:`TODO-9-induction`, ``case`` :ref:`TODO-9-induction` and ``inversion`` :ref:`TODO-8.14-inversion` tactics. +See also: The :tacn:`induction`, :tacn:`case`, and :tacn:`inversion` tactics. autorewrite @@ -403,6 +405,8 @@ Example 2: Mac Carthy function autorewrite with base1 using reflexivity || simpl. +.. _quote: + quote ----- @@ -544,8 +548,7 @@ Combining variables and constants ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ One can have both variables and constants in abstracts terms; for -example, this is the case for the ``ring`` tactic -:ref:`TODO-25-ringandfieldtacticfamilies`. Then one must provide to +example, this is the case for the :tacn:`ring` tactic. Then one must provide to ``quote`` a list of *constructors of constants*. For example, if the list is ``[O S]`` then closed natural numbers will be considered as constants and other terms as variables. @@ -606,7 +609,7 @@ don’t expect miracles from it! See also: comments of source file ``plugins/quote/quote.ml`` -See also: the ``ring`` tactic :ref:`TODO-25-ringandfieldtacticfamilies` +See also: the :tacn:`ring` tactic. Using the tactical language @@ -733,7 +736,7 @@ and this length is decremented for each rotation down to, but not including, 1 because for a list of length ``n``, we can make exactly ``n−1`` rotations to generate at most ``n`` distinct lists. Here, it must be noticed that we use the natural numbers of Coq for the -rotation counter. On Figure :ref:`TODO-9.1-tactic-language`, we can +rotation counter. In :ref:`ltac-syntax`, we can see that it is possible to use usual natural numbers but they are only used as arguments for primitive tactics and they cannot be handled, in particular, we cannot make computations with them. So, a natural @@ -830,7 +833,7 @@ The pattern matching on goals allows a complete and so a powerful backtracking when returning tactic values. An interesting application is the problem of deciding intuitionistic propositional logic. Considering the contraction-free sequent calculi LJT* of Roy Dyckhoff -:ref:`TODO-56-biblio`, it is quite natural to code such a tactic +:cite:`Dyc92`, it is quite natural to code such a tactic using the tactic language as shown on figures: :ref:`Deciding intuitionistic propositions (1) <decidingintuitionistic1>` and :ref:`Deciding intuitionistic propositions (2) @@ -868,7 +871,7 @@ Deciding type isomorphisms A more tricky problem is to decide equalities between types and modulo isomorphisms. Here, we choose to use the isomorphisms of the simply typed λ-calculus with Cartesian product and unit type (see, for -example, [:ref:`TODO-45`]). The axioms of this λ-calculus are given below. +example, :cite:`RC95`). The axioms of this λ-calculus are given below. .. coqtop:: in reset diff --git a/doc/sphinx/proof-engine/ltac.rst b/doc/sphinx/proof-engine/ltac.rst new file mode 100644 index 0000000000..88c1e225fd --- /dev/null +++ b/doc/sphinx/proof-engine/ltac.rst @@ -0,0 +1,1310 @@ +.. include:: ../preamble.rst +.. include:: ../replaces.rst + +.. _ltac: + +The tactic language +=================== + +This chapter gives a compact documentation of |Ltac|, the tactic language +available in |Coq|. We start by giving the syntax, and next, we present the +informal semantics. If you want to know more regarding this language and +especially about its foundations, you can refer to :cite:`Del00`. Chapter +:ref:`detailedexamplesoftactics` is devoted to giving examples of use of this +language on small but also with non-trivial problems. + +.. _ltac-syntax: + +Syntax +------ + +The syntax of the tactic language is given below. See Chapter +:ref:`gallinaspecificationlanguage` for a description of the BNF metasyntax used +in these grammar rules. Various already defined entries will be used in this +chapter: entries :token:`natural`, :token:`integer`, :token:`ident`, +:token:`qualid`, :token:`term`, :token:`cpattern` and :token:`atomic_tactic` +represent respectively the natural and integer numbers, the authorized +identificators and qualified names, Coq terms and patterns and all the atomic +tactics described in Chapter :ref:`tactics`. The syntax of :token:`cpattern` is +the same as that of terms, but it is extended with pattern matching +metavariables. In :token:`cpattern`, a pattern-matching metavariable is +represented with the syntax :g:`?id` where :g:`id` is an :token:`ident`. The +notation :g:`_` can also be used to denote metavariable whose instance is +irrelevant. In the notation :g:`?id`, the identifier allows us to keep +instantiations and to make constraints whereas :g:`_` shows that we are not +interested in what will be matched. On the right hand side of pattern-matching +clauses, the named metavariable are used without the question mark prefix. There +is also a special notation for second-order pattern-matching problems: in an +applicative pattern of the form :g:`@?id id1 … idn`, the variable id matches any +complex expression with (possible) dependencies in the variables :g:`id1 … idn` +and returns a functional term of the form :g:`fun id1 … idn => term`. + +The main entry of the grammar is :n:`@expr`. This language is used in proof +mode but it can also be used in toplevel definitions as shown below. + +.. note:: + + - The infix tacticals “… \|\| …”, “… + …”, and “… ; …” are associative. + + - In :token:`tacarg`, there is an overlap between qualid as a direct tactic + argument and :token:`qualid` as a particular case of term. The resolution is + done by first looking for a reference of the tactic language and if + it fails, for a reference to a term. To force the resolution as a + reference of the tactic language, use the form :g:`ltac:(@qualid)`. To + force the resolution as a reference to a term, use the syntax + :g:`(@qualid)`. + + - As shown by the figure, tactical ``\|\|`` binds more than the prefix + tacticals try, repeat, do and abstract which themselves bind more + than the postfix tactical “… ;[ … ]” which binds more than “… ; …”. + + For instance + + .. coqtop:: in + + try repeat tac1 || tac2; tac3; [tac31 | ... | tac3n]; tac4. + + is understood as + + .. coqtop:: in + + try (repeat (tac1 || tac2)); + ((tac3; [tac31 | ... | tac3n]); tac4). + +.. productionlist:: coq + expr : `expr` ; `expr` + : | [> `expr` | ... | `expr` ] + : | `expr` ; [ `expr` | ... | `expr` ] + : | `tacexpr3` + tacexpr3 : do (`natural` | `ident`) tacexpr3 + : | progress `tacexpr3` + : | repeat `tacexpr3` + : | try `tacexpr3` + : | once `tacexpr3` + : | exactly_once `tacexpr3` + : | timeout (`natural` | `ident`) `tacexpr3` + : | time [`string`] `tacexpr3` + : | only `selector`: `tacexpr3` + : | `tacexpr2` + tacexpr2 : `tacexpr1` || `tacexpr3` + : | `tacexpr1` + `tacexpr3` + : | tryif `tacexpr1` then `tacexpr1` else `tacexpr1` + : | `tacexpr1` + tacexpr1 : fun `name` ... `name` => `atom` + : | let [rec] `let_clause` with ... with `let_clause` in `atom` + : | match goal with `context_rule` | ... | `context_rule` end + : | match reverse goal with `context_rule` | ... | `context_rule` end + : | match `expr` with `match_rule` | ... | `match_rule` end + : | lazymatch goal with `context_rule` | ... | `context_rule` end + : | lazymatch reverse goal with `context_rule` | ... | `context_rule` end + : | lazymatch `expr` with `match_rule` | ... | `match_rule` end + : | multimatch goal with `context_rule` | ... | `context_rule` end + : | multimatch reverse goal with `context_rule` | ... | `context_rule` end + : | multimatch `expr` with `match_rule` | ... | `match_rule` end + : | abstract `atom` + : | abstract `atom` using `ident` + : | first [ `expr` | ... | `expr` ] + : | solve [ `expr` | ... | `expr` ] + : | idtac [ `message_token` ... `message_token`] + : | fail [`natural`] [`message_token` ... `message_token`] + : | fresh | fresh `string` | fresh `qualid` + : | context `ident` [`term`] + : | eval `redexpr` in `term` + : | type of `term` + : | constr : `term` + : | uconstr : `term` + : | type_term `term` + : | numgoals + : | guard `test` + : | assert_fails `tacexpr3` + : | assert_suceeds `tacexpr3` + : | `atomic_tactic` + : | `qualid` `tacarg` ... `tacarg` + : | `atom` + atom : `qualid` + : | () + : | `integer` + : | ( `expr` ) + message_token : `string` | `ident` | `integer` + tacarg : `qualid` + : | () + : | ltac : `atom` + : | `term` + let_clause : `ident` [`name` ... `name`] := `expr` + context_rule : `context_hyp`, ..., `context_hyp` |- `cpattern` => `expr` + : | `cpattern` => `expr` + : | |- `cpattern` => `expr` + : | _ => `expr` + context_hyp : `name` : `cpattern` + : | `name` := `cpattern` [: `cpattern`] + match_rule : `cpattern` => `expr` + : | context [ident] [ `cpattern` ] => `expr` + : | _ => `expr` + test : `integer` = `integer` + : | `integer` (< | <= | > | >=) `integer` + selector : [`ident`] + : | `integer` + : (`integer` | `integer` - `integer`), ..., (`integer` | `integer` - `integer`) + toplevel_selector : `selector` + : | `all` + : | `par` + +.. productionlist:: coq + top : [Local] Ltac `ltac_def` with ... with `ltac_def` + ltac_def : `ident` [`ident` ... `ident`] := `expr` + : | `qualid` [`ident` ... `ident`] ::= `expr` + +.. _ltac-semantics: + +Semantics +--------- + +Tactic expressions can only be applied in the context of a proof. The +evaluation yields either a term, an integer or a tactic. Intermediary +results can be terms or integers but the final result must be a tactic +which is then applied to the focused goals. + +There is a special case for ``match goal`` expressions of which the clauses +evaluate to tactics. Such expressions can only be used as end result of +a tactic expression (never as argument of a non recursive local +definition or of an application). + +The rest of this section explains the semantics of every construction of +|Ltac|. + +Sequence +~~~~~~~~ + +A sequence is an expression of the following form: + +.. tacn:: @expr ; @expr + :name: ltac-seq + + The expression :n:`@expr__1` is evaluated to :n:`v__1`, which must be + a tactic value. The tactic :n:`v__1` is applied to the current goal, + possibly producing more goals. Then :n:`@expr__2` is evaluated to + produce :n:`v__2`, which must be a tactic value. The tactic + :n:`v__2` is applied to all the goals produced by the prior + application. Sequence is associative. + +Local application of tactics +~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Different tactics can be applied to the different goals using the +following form: + +.. tacn:: [> {*| @expr }] + :name: [> ... | ... | ... ] (dispatch) + + The expressions :n:`@expr__i` are evaluated to :n:`v__i`, for + i=0,...,n and all have to be tactics. The :n:`v__i` is applied to the + i-th goal, for =1,...,n. It fails if the number of focused goals is not + exactly n. + + .. note:: + + If no tactic is given for the i-th goal, it behaves as if the tactic idtac + were given. For instance, ``[> | auto]`` is a shortcut for ``[> idtac | auto + ]``. + + .. tacv:: [> {*| @expr} | @expr .. | {*| @expr}] + + In this variant, token:`expr` is used for each goal coming after those + covered by the first list of :n:`@expr` but before those coevered by the + last list of :n:`@expr`. + + .. tacv:: [> {*| @expr} | .. | {*| @expr}] + + In this variant, idtac is used for the goals not covered by the two lists of + :n:`@expr`. + + .. tacv:: [> @expr .. ] + + In this variant, the tactic :n:`@expr` is applied independently to each of + the goals, rather than globally. In particular, if there are no goal, the + tactic is not run at all. A tactic which expects multiple goals, such as + ``swap``, would act as if a single goal is focused. + + .. tacv:: expr ; [{*| @expr}] + + This variant of local tactic application is paired with a sequence. In this + variant, there must be as many :n:`@expr` in the list as goals generated + by the application of the first :n:`@expr` to each of the individual goals + independently. All the above variants work in this form too. + Formally, :n:`@expr ; [ ... ]` is equivalent to :n:`[> @expr ; [> ... ] .. ]`. + +.. _goal-selectors: + +Goal selectors +~~~~~~~~~~~~~~ + +We can restrict the application of a tactic to a subset of the currently +focused goals with: + +.. tacn:: @toplevel_selector : @expr + :name: ... : ... (goal selector) + + We can also use selectors as a tactical, which allows to use them nested + in a tactic expression, by using the keyword ``only``: + + .. tacv:: only selector : expr + :name: only ... : ... + + When selecting several goals, the tactic expr is applied globally to all + selected goals. + + .. tacv:: [@ident] : @expr + + In this variant, :n:`@expr` is applied locally to a goal previously named + by the user (see :ref:`existential-variables`). + + .. tacv:: @num : @expr + + In this variant, :n:`@expr` is applied locally to the :token:`num`-th goal. + + .. tacv:: {+, @num-@num} : @expr + + In this variant, :n:`@expr` is applied globally to the subset of goals + described by the given ranges. You can write a single ``n`` as a shortcut + for ``n-n`` when specifying multiple ranges. + + .. tacv:: all: @expr + :name: all: ... + + In this variant, :n:`@expr` is applied to all focused goals. ``all:`` can only + be used at the toplevel of a tactic expression. + + .. tacv:: !: @expr + + In this variant, if exactly one goal is focused :n:`expr` is + applied to it. Otherwise the tactical fails. ``!:`` can only be + used at the toplevel of a tactic expression. + + .. tacv:: par: @expr + :name: par: ... + + In this variant, :n:`@expr` is applied to all focused goals in parallel. + The number of workers can be controlled via the command line option + ``-async-proofs-tac-j`` taking as argument the desired number of workers. + Limitations: ``par:`` only works on goals containing no existential + variables and :n:`@expr` must either solve the goal completely or do + nothing (i.e. it cannot make some progress). ``par:`` can only be used at + the toplevel of a tactic expression. + + .. exn:: No such goal. + :name: No such goal. (Goal selector) + + .. TODO change error message index entry + +For loop +~~~~~~~~ + +There is a for loop that repeats a tactic :token:`num` times: + +.. tacn:: do @num @expr + :name: do + + :n:`@expr` is evaluated to ``v`` which must be a tactic value. This tactic + value ``v`` is applied :token:`num` times. Supposing :token:`num` > 1, after the + first application of ``v``, ``v`` is applied, at least once, to the generated + subgoals and so on. It fails if the application of ``v`` fails before the num + applications have been completed. + +Repeat loop +~~~~~~~~~~~ + +We have a repeat loop with: + +.. tacn:: repeat @expr + :name: repeat + + :n:`@expr` is evaluated to ``v``. If ``v`` denotes a tactic, this tactic is + applied to each focused goal independently. If the application succeeds, the + tactic is applied recursively to all the generated subgoals until it eventually + fails. The recursion stops in a subgoal when the tactic has failed *to make + progress*. The tactic :n:`repeat @expr` itself never fails. + +Error catching +~~~~~~~~~~~~~~ + +We can catch the tactic errors with: + +.. tacn:: try @expr + :name: try + + :n:`@expr` is evaluated to ``v`` which must be a tactic value. The tactic + value ``v`` is applied to each focused goal independently. If the application of + ``v`` fails in a goal, it catches the error and leaves the goal unchanged. If the + level of the exception is positive, then the exception is re-raised with its + level decremented. + +Detecting progress +~~~~~~~~~~~~~~~~~~ + +We can check if a tactic made progress with: + +.. tacn:: progress expr + :name: progress + + :n:`@expr` is evaluated to v which must be a tactic value. The tactic value ``v`` + is applied to each focued subgoal independently. If the application of ``v`` + to one of the focused subgoal produced subgoals equal to the initial + goals (up to syntactical equality), then an error of level 0 is raised. + + .. exn:: Failed to progress. + +Backtracking branching +~~~~~~~~~~~~~~~~~~~~~~ + +We can branch with the following structure: + +.. tacn:: @expr__1 + @expr__2 + :name: + (backtracking branching) + + :n:`@expr__1` and :n:`@expr__2` are evaluated respectively to :n:`v__1` and + :n:`v__2` which must be tactic values. The tactic value :n:`v__1` is applied to + each focused goal independently and if it fails or a later tactic fails, then + the proof backtracks to the current goal and :n:`v__2` is applied. + + Tactics can be seen as having several successes. When a tactic fails it + asks for more successes of the prior tactics. + :n:`@expr__1 + @expr__2` has all the successes of :n:`v__1` followed by all the + successes of :n:`v__2`. Algebraically, + :n:`(@expr__1 + @expr__2); @expr__3 = (@expr__1; @expr__3) + (@expr__2; @expr__3)`. + + Branching is left-associative. + +First tactic to work +~~~~~~~~~~~~~~~~~~~~ + +Backtracking branching may be too expensive. In this case we may +restrict to a local, left biased, branching and consider the first +tactic to work (i.e. which does not fail) among a panel of tactics: + +.. tacn:: first [{*| @expr}] + :name: first + + The :n:`@expr__i` are evaluated to :n:`v__i` and :n:`v__i` must be + tactic values, for i=1,...,n. Supposing n>1, it applies, in each focused + goal independently, :n:`v__1`, if it works, it stops otherwise it + tries to apply :n:`v__2` and so on. It fails when there is no + applicable tactic. In other words, + :n:`first [:@expr__1 | ... | @expr__n]` behaves, in each goal, as the the first + :n:`v__i` to have *at least* one success. + + .. exn:: No applicable tactic. + + .. tacv:: first @expr + + This is an |Ltac| alias that gives a primitive access to the first + tactical as a |Ltac| definition without going through a parsing rule. It + expects to be given a list of tactics through a ``Tactic Notation``, + allowing to write notations of the following form: + + .. example:: + + .. coqtop:: in + + Tactic Notation "foo" tactic_list(tacs) := first tacs. + +Left-biased branching +~~~~~~~~~~~~~~~~~~~~~ + +Yet another way of branching without backtracking is the following +structure: + +.. tacn:: @expr__1 || @expr__2 + :name: || (left-biased branching) + + :n:`@expr__1` and :n:`@expr__2` are evaluated respectively to :n:`v__1` and + :n:`v__2` which must be tactic values. The tactic value :n:`v__1` is + applied in each subgoal independently and if it fails *to progress* then + :n:`v__2` is applied. :n:`@expr__1 || @expr__2` is + equivalent to :n:`first [ progress @expr__1 | @expr__2 ]` (except that + if it fails, it fails like :n:`v__2`). Branching is left-associative. + +Generalized biased branching +~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The tactic + +.. tacn:: tryif @expr__1 then @expr__2 else @expr__3 + :name: tryif + + is a generalization of the biased-branching tactics above. The + expression :n:`@expr__1` is evaluated to :n:`v__1`, which is then + applied to each subgoal independently. For each goal where :n:`v__1` + succeeds at least once, :n:`@expr__2` is evaluated to :n:`v__2` which + is then applied collectively to the generated subgoals. The :n:`v__2` + tactic can trigger backtracking points in :n:`v__1`: where :n:`v__1` + succeeds at least once, + :n:`tryif @expr__1 then @expr__2 else @expr__3` is equivalent to + :n:`v__1; v__2`. In each of the goals where :n:`v__1` does not succeed at least + once, :n:`@expr__3` is evaluated in :n:`v__3` which is is then applied to the + goal. + +Soft cut +~~~~~~~~ + +Another way of restricting backtracking is to restrict a tactic to a +single success *a posteriori*: + +.. tacn:: once @expr + :name: once + + :n:`@expr` is evaluated to ``v`` which must be a tactic value. The tactic value + ``v`` is applied but only its first success is used. If ``v`` fails, + :n:`once @expr` fails like ``v``. If ``v`` has a least one success, + :n:`once @expr` succeeds once, but cannot produce more successes. + +Checking the successes +~~~~~~~~~~~~~~~~~~~~~~ + +Coq provides an experimental way to check that a tactic has *exactly +one* success: + +.. tacn:: exactly_once @expr + :name: exactly_once + + :n:`@expr` is evaluated to ``v`` which must be a tactic value. The tactic value + ``v`` is applied if it has at most one success. If ``v`` fails, + :n:`exactly_once @expr` fails like ``v``. If ``v`` has a exactly one success, + :n:`exactly_once @expr` succeeds like ``v``. If ``v`` has two or more + successes, exactly_once expr fails. + + .. warning:: + + The experimental status of this tactic pertains to the fact if ``v`` + performs side effects, they may occur in a unpredictable way. Indeed, + normally ``v`` would only be executed up to the first success until + backtracking is needed, however exactly_once needs to look ahead to see + whether a second success exists, and may run further effects + immediately. + + .. exn:: This tactic has more than one success. + +Checking the failure +~~~~~~~~~~~~~~~~~~~~ + +Coq provides a derived tactic to check that a tactic *fails*: + +.. tacn:: assert_fails @expr + :name: assert_fails + + This behaves like :n:`tryif @expr then fail 0 tac "succeeds" else idtac`. + +Checking the success +~~~~~~~~~~~~~~~~~~~~ + +Coq provides a derived tactic to check that a tactic has *at least one* +success: + +.. tacn:: assert_succeeds @expr + :name: assert_suceeds + + This behaves like + :n:`tryif (assert_fails tac) then fail 0 tac "fails" else idtac`. + +Solving +~~~~~~~ + +We may consider the first to solve (i.e. which generates no subgoal) +among a panel of tactics: + +.. tacn:: solve [{*| @expr}] + :name: solve + + The :n:`@expr__i` are evaluated to :n:`v__i` and :n:`v__i` must be + tactic values, for i=1,...,n. Supposing n>1, it applies :n:`v__1` to + each goal independently, if it doesn’t solve the goal then it tries to + apply :n:`v__2` and so on. It fails if there is no solving tactic. + + .. exn:: Cannot solve the goal. + + .. tacv:: solve @expr + + This is an |Ltac| alias that gives a primitive access to the :n:`solve:` + tactical. See the :n:`first` tactical for more information. + +Identity +~~~~~~~~ + +The constant :n:`idtac` is the identity tactic: it leaves any goal unchanged but +it appears in the proof script. + +.. tacn:: idtac {* message_token} + :name: idtac + + This prints the given tokens. Strings and integers are printed + literally. If a (term) variable is given, its contents are printed. + +Failing +~~~~~~~ + +.. tacn:: fail + :name: fail + + This is the always-failing tactic: it does not solve any + goal. It is useful for defining other tacticals since it can be caught by + :tacn:`try`, :tacn:`repeat`, :tacn:`match goal`, or the branching tacticals. The + :tacn:`fail` tactic will, however, succeed if all the goals have already been + solved. + + .. tacv:: fail @num + + The number is the failure level. If no level is specified, it defaults to 0. + The level is used by :tacn:`try`, :tacn:`repeat`, :tacn:`match goal` and the branching + tacticals. If 0, it makes :tacn:`match goal` considering the next clause + (backtracking). If non zero, the current :tacn:`match goal` block, :tacn:`try`, + :tacn:`repeat`, or branching command is aborted and the level is decremented. In + the case of :n:`+`, a non-zero level skips the first backtrack point, even if + the call to :n:`fail @num` is not enclosed in a :n:`+` command, + respecting the algebraic identity. + + .. tacv:: fail {* message_token} + + The given tokens are used for printing the failure message. + + .. tacv:: fail @num {* message_token} + + This is a combination of the previous variants. + + .. tacv:: gfail + :name: gfail + + This variant fails even if there are no goals left. + + .. tacv:: gfail {* message_token} + + .. tacv:: gfail @num {* message_token} + + These variants fail with an error message or an error level even if + there are no goals left. Be careful however if Coq terms have to be + printed as part of the failure: term construction always forces the + tactic into the goals, meaning that if there are no goals when it is + evaluated, a tactic call like :n:`let x:=H in fail 0 x` will succeed. + + .. exn:: Tactic Failure message (level @num). + +Timeout +~~~~~~~ + +We can force a tactic to stop if it has not finished after a certain +amount of time: + +.. tacn:: timeout @num @expr + :name: timeout + + :n:`@expr` is evaluated to ``v`` which must be a tactic value. The tactic value + ``v`` is applied normally, except that it is interrupted after :n:`@num` seconds + if it is still running. In this case the outcome is a failure. + + .. warning:: + + For the moment, timeout is based on elapsed time in seconds, + which is very machine-dependent: a script that works on a quick machine + may fail on a slow one. The converse is even possible if you combine a + timeout with some other tacticals. This tactical is hence proposed only + for convenience during debug or other development phases, we strongly + advise you to not leave any timeout in final scripts. Note also that + this tactical isn’t available on the native Windows port of Coq. + +Timing a tactic +~~~~~~~~~~~~~~~ + +A tactic execution can be timed: + +.. tacn:: time @string @expr + :name: time + + evaluates :n:`@expr` and displays the time the tactic expression ran, whether it + fails or successes. In case of several successes, the time for each successive + runs is displayed. Time is in seconds and is machine-dependent. The :n:`@string` + argument is optional. When provided, it is used to identify this particular + occurrence of time. + +Timing a tactic that evaluates to a term +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Tactic expressions that produce terms can be timed with the experimental +tactic + +.. tacn:: time_constr expr + :name: time_constr + + which evaluates :n:`@expr ()` and displays the time the tactic expression + evaluated, assuming successful evaluation. Time is in seconds and is + machine-dependent. + + This tactic currently does not support nesting, and will report times + based on the innermost execution. This is due to the fact that it is + implemented using the tactics + + .. tacn:: restart_timer @string + :name: restart_timer + + and + + .. tacn:: finish_timing {? @string} @string + :name: finish_timing + + which (re)set and display an optionally named timer, respectively. The + parenthesized string argument to :n:`finish_timing` is also optional, and + determines the label associated with the timer for printing. + + By copying the definition of :n:`time_constr` from the standard library, + users can achive support for a fixed pattern of nesting by passing + different :n:`@string` parameters to :n:`restart_timer` and :n:`finish_timing` + at each level of nesting. + + .. example:: + + .. coqtop:: all + + Ltac time_constr1 tac := + let eval_early := match goal with _ => restart_timer "(depth 1)" end in + let ret := tac () in + let eval_early := match goal with _ => finish_timing ( "Tactic evaluation" ) "(depth 1)" end in + ret. + + Goal True. + let v := time_constr + ltac:(fun _ => + let x := time_constr1 ltac:(fun _ => constr:(10 * 10)) in + let y := time_constr1 ltac:(fun _ => eval compute in x) in + y) in + pose v. + Abort. + +Local definitions +~~~~~~~~~~~~~~~~~ + +Local definitions can be done as follows: + +.. tacn:: let @ident__1 := @expr__1 {* with @ident__i := @expr__i} in @expr + + each :n:`@expr__i` is evaluated to :n:`v__i`, then, :n:`@expr` is evaluated + by substituting :n:`v__i` to each occurrence of :n:`@ident__i`, for + i=1,...,n. There is no dependencies between the :n:`@expr__i` and the + :n:`@ident__i`. + + Local definitions can be recursive by using :n:`let rec` instead of :n:`let`. + In this latter case, the definitions are evaluated lazily so that the rec + keyword can be used also in non recursive cases so as to avoid the eager + evaluation of local definitions. + + .. but rec changes the binding!! + +Application +~~~~~~~~~~~ + +An application is an expression of the following form: + +.. tacn:: @qualid {+ @tacarg} + + The reference :n:`@qualid` must be bound to some defined tactic definition + expecting at least as many arguments as the provided :n:`tacarg`. The + expressions :n:`@expr__i` are evaluated to :n:`v__i`, for i=1,...,n. + + .. what expressions ?? + +Function construction +~~~~~~~~~~~~~~~~~~~~~ + +A parameterized tactic can be built anonymously (without resorting to +local definitions) with: + +.. tacn:: fun {+ @ident} => @expr + + Indeed, local definitions of functions are a syntactic sugar for binding + a :n:`fun` tactic to an identifier. + +Pattern matching on terms +~~~~~~~~~~~~~~~~~~~~~~~~~ + +We can carry out pattern matching on terms with: + +.. tacn:: match @expr with {+| @cpattern__i => @expr__i} end + + The expression :n:`@expr` is evaluated and should yield a term which is + matched against :n:`cpattern__1`. The matching is non-linear: if a + metavariable occurs more than once, it should match the same expression + every time. It is first-order except on the variables of the form :n:`@?id` + that occur in head position of an application. For these variables, the + matching is second-order and returns a functional term. + + Alternatively, when a metavariable of the form :n:`?id` occurs under binders, + say :n:`x__1, …, x__n` and the expression matches, the + metavariable is instantiated by a term which can then be used in any + context which also binds the variables :n:`x__1, …, x__n` with + same types. This provides with a primitive form of matching under + context which does not require manipulating a functional term. + + If the matching with :n:`@cpattern__1` succeeds, then :n:`@expr__1` is + evaluated into some value by substituting the pattern matching + instantiations to the metavariables. If :n:`@expr__1` evaluates to a + tactic and the match expression is in position to be applied to a goal + (e.g. it is not bound to a variable by a :n:`let in`), then this tactic is + applied. If the tactic succeeds, the list of resulting subgoals is the + result of the match expression. If :n:`@expr__1` does not evaluate to a + tactic or if the match expression is not in position to be applied to a + goal, then the result of the evaluation of :n:`@expr__1` is the result + of the match expression. + + If the matching with :n:`@cpattern__1` fails, or if it succeeds but the + evaluation of :n:`@expr__1` fails, or if the evaluation of + :n:`@expr__1` succeeds but returns a tactic in execution position whose + execution fails, then :n:`cpattern__2` is used and so on. The pattern + :n:`_` matches any term and shunts all remaining patterns if any. If all + clauses fail (in particular, there is no pattern :n:`_`) then a + no-matching-clause error is raised. + + Failures in subsequent tactics do not cause backtracking to select new + branches or inside the right-hand side of the selected branch even if it + has backtracking points. + + .. exn:: No matching clauses for match. + + No pattern can be used and, in particular, there is no :n:`_` pattern. + + .. exn:: Argument of match does not evaluate to a term. + + This happens when :n:`@expr` does not denote a term. + + .. tacv:: multimatch @expr with {+| @cpattern__i => @expr__i} end + + Using multimatch instead of match will allow subsequent tactics to + backtrack into a right-hand side tactic which has backtracking points + left and trigger the selection of a new matching branch when all the + backtracking points of the right-hand side have been consumed. + + The syntax :n:`match …` is, in fact, a shorthand for :n:`once multimatch …`. + + .. tacv:: lazymatch @expr with {+| @cpattern__i => @expr__i} end + + Using lazymatch instead of match will perform the same pattern + matching procedure but will commit to the first matching branch + rather than trying a new matching if the right-hand side fails. If + the right-hand side of the selected branch is a tactic with + backtracking points, then subsequent failures cause this tactic to + backtrack. + + .. tacv:: context @ident [@cpattern] + + This special form of patterns matches any term with a subterm matching + cpattern. If there is a match, the optional :n:`@ident` is assigned the "matched + context", i.e. the initial term where the matched subterm is replaced by a + hole. The example below will show how to use such term contexts. + + If the evaluation of the right-hand-side of a valid match fails, the next + matching subterm is tried. If no further subterm matches, the next clause + is tried. Matching subterms are considered top-bottom and from left to + right (with respect to the raw printing obtained by setting option + :opt:`Printing All`). + + .. example:: + + .. coqtop:: all + + Ltac f x := + match x with + context f [S ?X] => + idtac X; (* To display the evaluation order *) + assert (p := eq_refl 1 : X=1); (* To filter the case X=1 *) + let x:= context f[O] in assert (x=O) (* To observe the context *) + end. + Goal True. + f (3+4). + +.. _ltac-match-goal: + +Pattern matching on goals +~~~~~~~~~~~~~~~~~~~~~~~~~ + +We can make pattern matching on goals using the following expression: + +.. we should provide the full grammar here + +.. tacn:: match goal with {+| {+ hyp} |- @cpattern => @expr } | _ => @expr end + :name: match goal + + If each hypothesis pattern :n:`hyp`\ :sub:`1,i`, with i=1,...,m\ :sub:`1` is + matched (non-linear first-order unification) by an hypothesis of the + goal and if :n:`cpattern_1` is matched by the conclusion of the goal, + then :n:`@expr__1` is evaluated to :n:`v__1` by substituting the + pattern matching to the metavariables and the real hypothesis names + bound to the possible hypothesis names occurring in the hypothesis + patterns. If :n:`v__1` is a tactic value, then it is applied to the + goal. If this application fails, then another combination of hypotheses + is tried with the same proof context pattern. If there is no other + combination of hypotheses then the second proof context pattern is tried + and so on. If the next to last proof context pattern fails then + the last :n:`@expr` is evaluated to :n:`v` and :n:`v` is + applied. Note also that matching against subterms (using the :n:`context + @ident [ @cpattern ]`) is available and is also subject to yielding several + matchings. + + Failures in subsequent tactics do not cause backtracking to select new + branches or combinations of hypotheses, or inside the right-hand side of + the selected branch even if it has backtracking points. + + .. exn:: No matching clauses for match goal. + + No clause succeeds, i.e. all matching patterns, if any, fail at the + application of the right-hand-side. + + .. note:: + + It is important to know that each hypothesis of the goal can be matched + by at most one hypothesis pattern. The order of matching is the + following: hypothesis patterns are examined from the right to the left + (i.e. hyp\ :sub:`i,m`\ :sub:`i`` before hyp\ :sub:`i,1`). For each + hypothesis pattern, the goal hypothesis are matched in order (fresher + hypothesis first), but it possible to reverse this order (older first) + with the :n:`match reverse goal with` variant. + + .. tacv:: multimatch goal with {+| {+ hyp} |- @cpattern => @expr } | _ => @expr end + + Using :n:`multimatch` instead of :n:`match` will allow subsequent tactics + to backtrack into a right-hand side tactic which has backtracking points + left and trigger the selection of a new matching branch or combination of + hypotheses when all the backtracking points of the right-hand side have + been consumed. + + The syntax :n:`match [reverse] goal …` is, in fact, a shorthand for + :n:`once multimatch [reverse] goal …`. + + .. tacv:: lazymatch goal with {+| {+ hyp} |- @cpattern => @expr } | _ => @expr end + + Using lazymatch instead of match will perform the same pattern matching + procedure but will commit to the first matching branch with the first + matching combination of hypotheses rather than trying a new matching if + the right-hand side fails. If the right-hand side of the selected branch + is a tactic with backtracking points, then subsequent failures cause + this tactic to backtrack. + +Filling a term context +~~~~~~~~~~~~~~~~~~~~~~ + +The following expression is not a tactic in the sense that it does not +produce subgoals but generates a term to be used in tactic expressions: + +.. tacn:: context @ident [@expr] + + :n:`@ident` must denote a context variable bound by a context pattern of a + match expression. This expression evaluates replaces the hole of the + value of :n:`@ident` by the value of :n:`@expr`. + + .. exn:: Not a context variable. + +Generating fresh hypothesis names +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Tactics sometimes have to generate new names for hypothesis. Letting the +system decide a name with the intro tactic is not so good since it is +very awkward to retrieve the name the system gave. The following +expression returns an identifier: + +.. tacn:: fresh {* component} + + It evaluates to an identifier unbound in the goal. This fresh identifier + is obtained by concatenating the value of the :n:`@component`s (each of them + is, either a :n:`@qualid` which has to refer to a (unqualified) name, or + directly a name denoted by a :n:`@string`). + + .. I don't understand this component thing. Couldn't we give the grammar? + + If the resulting name is already used, it is padded with a number so that it + becomes fresh. If no component is given, the name is a fresh derivative of + the name ``H``. + +Computing in a constr +~~~~~~~~~~~~~~~~~~~~~ + +Evaluation of a term can be performed with: + +.. tacn:: eval @redexpr in @term + + where :n:`@redexpr` is a reduction tactic among :tacn:`red`, :tacn:`hnf`, + :tacn:`compute`, :tacn:`simpl`, :tacn:`cbv`, :tacn:`lazy`, :tacn:`unfold`, + :tacn:`fold`, :tacn:`pattern`. + +Recovering the type of a term +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The following returns the type of term: + +.. tacn:: type of @term + +Manipulating untyped terms +~~~~~~~~~~~~~~~~~~~~~~~~~~ + +.. tacn:: uconstr : @term + + The terms built in |Ltac| are well-typed by default. It may not be + appropriate for building large terms using a recursive |Ltac| function: the + term has to be entirely type checked at each step, resulting in potentially + very slow behavior. It is possible to build untyped terms using |Ltac| with + the :n:`uconstr : @term` syntax. + +.. tacn:: type_term @term + + An untyped term, in |Ltac|, can contain references to hypotheses or to + |Ltac| variables containing typed or untyped terms. An untyped term can be + type-checked using the function type_term whose argument is parsed as an + untyped term and returns a well-typed term which can be used in tactics. + +Untyped terms built using :n:`uconstr :` can also be used as arguments to the +:tacn:`refine` tactic. In that case the untyped term is type +checked against the conclusion of the goal, and the holes which are not solved +by the typing procedure are turned into new subgoals. + +Counting the goals +~~~~~~~~~~~~~~~~~~ + +.. tacn:: numgoals + + The number of goals under focus can be recovered using the :n:`numgoals` + function. Combined with the guard command below, it can be used to + branch over the number of goals produced by previous tactics. + + .. example:: + + .. coqtop:: in + + Ltac pr_numgoals := let n := numgoals in idtac "There are" n "goals". + + Goal True /\ True /\ True. + split;[|split]. + + .. coqtop:: all + + all:pr_numgoals. + +Testing boolean expressions +~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +.. tacn:: guard @test + :name: guard + + The :tacn:`guard` tactic tests a boolean expression, and fails if the expression + evaluates to false. If the expression evaluates to true, it succeeds + without affecting the proof. + + The accepted tests are simple integer comparisons. + + .. example:: + + .. coqtop:: in + + Goal True /\ True /\ True. + split;[|split]. + + .. coqtop:: all + + all:let n:= numgoals in guard n<4. + Fail all:let n:= numgoals in guard n=2. + + .. exn:: Condition not satisfied. + +Proving a subgoal as a separate lemma +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +.. tacn:: abstract @expr + :name: abstract + + From the outside, :n:`abstract @expr` is the same as :n:`solve @expr`. + Internally it saves an auxiliary lemma called ``ident_subproofn`` where + ``ident`` is the name of the current goal and ``n`` is chosen so that this is + a fresh name. Such an auxiliary lemma is inlined in the final proof term. + + This tactical is useful with tactics such as :tacn:`omega` or + :tacn:`discriminate` that generate huge proof terms. With that tool the user + can avoid the explosion at time of the Save command without having to cut + manually the proof in smaller lemmas. + + It may be useful to generate lemmas minimal w.r.t. the assumptions they + depend on. This can be obtained thanks to the option below. + + .. tacv:: abstract @expr using @ident + + Give explicitly the name of the auxiliary lemma. + + .. warning:: + + Use this feature at your own risk; explicitly named and reused subterms + don’t play well with asynchronous proofs. + + .. tacv:: transparent_abstract @expr + :name: transparent_abstract + + Save the subproof in a transparent lemma rather than an opaque one. + + .. warning:: + + Use this feature at your own risk; building computationally relevant + terms with tactics is fragile. + + .. tacv:: transparent_abstract @expr using @ident + + Give explicitly the name of the auxiliary transparent lemma. + + .. warning:: + + Use this feature at your own risk; building computationally relevant terms + with tactics is fragile, and explicitly named and reused subterms + don’t play well with asynchronous proofs. + + .. exn:: Proof is not complete. + :name: Proof is not complete. (abstract) + +Tactic toplevel definitions +--------------------------- + +Defining |Ltac| functions +~~~~~~~~~~~~~~~~~~~~~~~~~ + +Basically, |Ltac| toplevel definitions are made as follows: + +.. cmd:: Ltac @ident {* @ident} := @expr + + This defines a new |Ltac| function that can be used in any tactic + script or new |Ltac| toplevel definition. + + .. note:: + + The preceding definition can equivalently be written: + + :n:`Ltac @ident := fun {+ @ident} => @expr` + + Recursive and mutual recursive function definitions are also possible + with the syntax: + + .. cmdv:: Ltac @ident {* @ident} {* with @ident {* @ident}} := @expr + + It is also possible to *redefine* an existing user-defined tactic using the syntax: + + .. cmdv:: Ltac @qualid {* @ident} ::= @expr + + A previous definition of qualid must exist in the environment. The new + definition will always be used instead of the old one and it goes across + module boundaries. + + If preceded by the keyword Local the tactic definition will not be + exported outside the current module. + +Printing |Ltac| tactics +~~~~~~~~~~~~~~~~~~~~~~~ + +.. cmd:: Print Ltac @qualid + + Defined |Ltac| functions can be displayed using this command. + +.. cmd:: Print Ltac Signatures + + This command displays a list of all user-defined tactics, with their arguments. + +Debugging |Ltac| tactics +------------------------ + +Info trace +~~~~~~~~~~ + +.. cmd:: Info @num @expr + :name: Info + + This command can be used to print the trace of the path eventually taken by an + |Ltac| script. That is, the list of executed tactics, discarding + all the branches which have failed. To that end the :cmd:`Info` command can be + used with the following syntax. + + + The number :n:`@num` is the unfolding level of tactics in the trace. At level + 0, the trace contains a sequence of tactics in the actual script, at level 1, + the trace will be the concatenation of the traces of these tactics, etc… + + .. example:: + + .. coqtop:: in reset + + Ltac t x := exists x; reflexivity. + Goal exists n, n=0. + + .. coqtop:: all + + Info 0 t 1||t 0. + + .. coqtop:: in + + Undo. + + .. coqtop:: all + + Info 1 t 1||t 0. + + The trace produced by :cmd:`Info` tries its best to be a reparsable + |Ltac| script, but this goal is not achievable in all generality. + So some of the output traces will contain oddities. + + As an additional help for debugging, the trace produced by :cmd:`Info` contains + (in comments) the messages produced by the :tacn:`idtac` tactical at the right + position in the script. In particular, the calls to idtac in branches which failed are + not printed. + + .. opt:: Info Level @num + + This option is an alternative to the :cmd:`Info` command. + + This will automatically print the same trace as :n:`Info @num` at each + tactic call. The unfolding level can be overridden by a call to the + :cmd:`Info` command. + +Interactive debugger +~~~~~~~~~~~~~~~~~~~~ + +.. opt:: Ltac Debug + + This option governs the step-by-step debugger that comes with the |Ltac| interpreter + +When the debugger is activated, it stops at every step of the evaluation of +the current |Ltac| expression and it prints information on what it is doing. +The debugger stops, prompting for a command which can be one of the +following: + ++-----------------+-----------------------------------------------+ +| simple newline: | go to the next step | ++-----------------+-----------------------------------------------+ +| h: | get help | ++-----------------+-----------------------------------------------+ +| x: | exit current evaluation | ++-----------------+-----------------------------------------------+ +| s: | continue current evaluation without stopping | ++-----------------+-----------------------------------------------+ +| r n: | advance n steps further | ++-----------------+-----------------------------------------------+ +| r string: | advance up to the next call to “idtac string” | ++-----------------+-----------------------------------------------+ + +A non-interactive mode for the debugger is available via the option: + +.. opt:: Ltac Batch Debug + + This option has the effect of presenting a newline at every prompt, when + the debugger is on. The debug log thus created, which does not require + user input to generate when this option is set, can then be run through + external tools such as diff. + +Profiling |Ltac| tactics +~~~~~~~~~~~~~~~~~~~~~~~~ + +It is possible to measure the time spent in invocations of primitive +tactics as well as tactics defined in |Ltac| and their inner +invocations. The primary use is the development of complex tactics, +which can sometimes be so slow as to impede interactive usage. The +reasons for the performence degradation can be intricate, like a slowly +performing |Ltac| match or a sub-tactic whose performance only +degrades in certain situations. The profiler generates a call tree and +indicates the time spent in a tactic depending its calling context. Thus +it allows to locate the part of a tactic definition that contains the +performance bug. + +.. opt:: Ltac Profiling + + This option enables and disables the profiler. + +.. cmd:: Show Ltac Profile + + Prints the profile + + .. cmdv:: Show Ltac Profile @string + + Prints a profile for all tactics that start with :n:`@string`. Append a period + (.) to the string if you only want exactly that name. + +.. cmd:: Reset Ltac Profile + + Resets the profile, that is, deletes all accumulated information. + + .. warning:: + + Backtracking across a :cmd:`Reset Ltac Profile` will not restore the information. + +.. coqtop:: reset in + + Require Import Coq.omega.Omega. + + Ltac mytauto := tauto. + Ltac tac := intros; repeat split; omega || mytauto. + + Notation max x y := (x + (y - x)) (only parsing). + + Goal forall x y z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z, + max x (max y z) = max (max x y) z /\ max x (max y z) = max (max x y) z + /\ (A /\ B /\ C /\ D /\ E /\ F /\ G /\ H /\ I /\ J /\ K /\ L /\ M /\ N /\ O /\ P /\ Q /\ R /\ S /\ T /\ U /\ V /\ W /\ X /\ Y /\ Z + -> Z /\ Y /\ X /\ W /\ V /\ U /\ T /\ S /\ R /\ Q /\ P /\ O /\ N /\ M /\ L /\ K /\ J /\ I /\ H /\ G /\ F /\ E /\ D /\ C /\ B /\ A). + Proof. + +.. coqtop:: all + + Set Ltac Profiling. + tac. + Show Ltac Profile. + Show Ltac Profile "omega". + +.. coqtop:: in + + Abort. + Unset Ltac Profiling. + +.. tacn:: start ltac profiling + :name: start ltac profiling + + This tactic behaves like :tacn:`idtac` but enables the profiler. + +.. tacn:: stop ltac profiling + :name: stop ltac profiling + + Similarly to :tacn:`start ltac profiling`, this tactic behaves like + :tacn:`idtac`. Together, they allow you to exclude parts of a proof script + from profiling. + +.. tacn:: reset ltac profile + :name: reset ltac profile + + This tactic behaves like the corresponding vernacular command + and allow displaying and resetting the profile from tactic scripts for + benchmarking purposes. + +.. tacn:: show ltac profile + :name: show ltac profile + + This tactic behaves like the corresponding vernacular command + and allow displaying and resetting the profile from tactic scripts for + benchmarking purposes. + +.. tacn:: show ltac profile @string + :name: show ltac profile + + This tactic behaves like the corresponding vernacular command + and allow displaying and resetting the profile from tactic scripts for + benchmarking purposes. + +You can also pass the ``-profile-ltac`` command line option to ``coqc``, which +turns the :opt:`Ltac Profiling` option on at the beginning of each document, +and performs a :cmd:`Show Ltac Profile` at the end. + +.. warning:: + + Note that the profiler currently does not handle backtracking into + multi-success tactics, and issues a warning to this effect in many cases + when such backtracking occurs. + +Run-time optimization tactic +~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +.. tacn:: optimize_heap + :name: optimize_heap + +This tactic behaves like :n:`idtac`, except that running it compacts the +heap in the OCaml run-time system. It is analogous to the Vernacular +command :cmd:`Optimize Heap`. diff --git a/doc/sphinx/proof-engine/proof-handling.rst b/doc/sphinx/proof-engine/proof-handling.rst index 52cde52c69..eba0db3ff5 100644 --- a/doc/sphinx/proof-engine/proof-handling.rst +++ b/doc/sphinx/proof-engine/proof-handling.rst @@ -8,176 +8,190 @@ In |Coq|’s proof editing mode all top-level commands documented in Chapter :ref:`vernacularcommands` remain available and the user has access to specialized commands dealing with proof development pragmas documented in this -section. He can also use some other specialized commands called +section. They can also use some other specialized commands called *tactics*. They are the very tools allowing the user to deal with logical reasoning. They are documented in Chapter :ref:`tactics`. -When switching in editing proof mode, the prompt ``Coq <`` is changed into -``ident <`` where ``ident`` is the declared name of the theorem currently -edited. + +Coq user interfaces usually have a way of marking whether the user has +switched to proof editing mode. For instance, in coqtop the prompt ``Coq <`` is changed into +:n:`@ident <` where :token:`ident` is the declared name of the theorem currently edited. At each stage of a proof development, one has a list of goals to prove. Initially, the list consists only in the theorem itself. After having applied some tactics, the list of goals contains the subgoals generated by the tactics. -To each subgoal is associated a number of hypotheses called the *local -context* of the goal. Initially, the local context contains the local -variables and hypotheses of the current section (see Section :ref:`TODO_gallina_assumptions`) -and the local variables and hypotheses of the theorem statement. It is -enriched by the use of certain tactics (see e.g. ``intro`` in Section -:ref:`managingthelocalcontext`). +To each subgoal is associated a number of hypotheses called the *local context* +of the goal. Initially, the local context contains the local variables and +hypotheses of the current section (see Section :ref:`gallina-assumptions`) and +the local variables and hypotheses of the theorem statement. It is enriched by +the use of certain tactics (see e.g. :tacn:`intro`). When a proof is completed, the message ``Proof completed`` is displayed. One can then register this proof as a defined constant in the environment. Because there exists a correspondence between proofs and -terms of λ-calculus, known as the *Curry-Howard isomorphism* [[How80]_, -[Bar81]_, [Gir89]_, [Hue88]_ ], |Coq| -stores proofs as terms of |Cic|. Those terms -are called *proof terms*. +terms of λ-calculus, known as the *Curry-Howard isomorphism* +:cite:`How80,Bar81,Gir89,Hue88`, |Coq| stores proofs as terms of |Cic|. Those +terms are called *proof terms*. + +.. exn:: No focused proof. -.. exn:: No focused proof + Coq raises this error message when one attempts to use a proof editing command + out of the proof editing mode. -Coq raises this error message when one attempts to use a proof editing command -out of the proof editing mode. +.. _proof-editing-mode: Switching on/off the proof editing mode ------------------------------------------- -The proof editing mode is entered by asserting a statement, which -typically is the assertion of a theorem: - -.. cmd:: Theorem @ident [@binders] : @form. +The proof editing mode is entered by asserting a statement, which typically is +the assertion of a theorem using an assertion command like :cmd:`Theorem`. The +list of assertion commands is given in :ref:`Assertions`. The command +:cmd:`Goal` can also be used. -The list of assertion commands is given in Section :ref:TODO-assertions_and_proof`. The -command ``Goal`` can also be used. +.. cmd:: Goal @form -.. cmd:: Goal @form. + This is intended for quick assertion of statements, without knowing in + advance which name to give to the assertion, typically for quick + testing of the provability of a statement. If the proof of the + statement is eventually completed and validated, the statement is then + bound to the name ``Unnamed_thm`` (or a variant of this name not already + used for another statement). -This is intended for quick assertion of statements, without knowing in -advance which name to give to the assertion, typically for quick -testing of the provability of a statement. If the proof of the -statement is eventually completed and validated, the statement is then -bound to the name ``Unnamed_thm`` (or a variant of this name not already -used for another statement). +.. cmd:: Qed -.. cmd:: Qed. + This command is available in interactive editing proof mode when the + proof is completed. Then :cmd:`Qed` extracts a proof term from the proof + script, switches back to Coq top-level and attaches the extracted + proof term to the declared name of the original goal. This name is + added to the environment as an opaque constant. -This command is available in interactive editing proof mode when the -proof is completed. Then ``Qed`` extracts a proof term from the proof -script, switches back to Coq top-level and attaches the extracted -proof term to the declared name of the original goal. This name is -added to the environment as an ``Opaque`` constant. + .. exn:: Attempt to save an incomplete proof. + .. note:: -.. exn:: Attempt to save an incomplete proof - -.. note:: - - Sometimes an error occurs when building the proof term, because - tactics do not enforce completely the term construction - constraints. + Sometimes an error occurs when building the proof term, because + tactics do not enforce completely the term construction + constraints. -The user should also be aware of the fact that since the -proof term is completely rechecked at this point, one may have to wait -a while when the proof is large. In some exceptional cases one may -even incur a memory overflow. + The user should also be aware of the fact that since the + proof term is completely rechecked at this point, one may have to wait + a while when the proof is large. In some exceptional cases one may + even incur a memory overflow. -.. cmdv:: Defined. + .. cmdv:: Defined + :name: Defined -Defines the proved term as a transparent constant. + Same as :cmd:`Qed` but the proof is then declared transparent, which means + that its content can be explicitly used for type-checking and that it can be + unfolded in conversion tactics (see :ref:`performingcomputations`, + :cmd:`Opaque`, :cmd:`Transparent`). -.. cmdv:: Save @ident. + .. cmdv:: Save @ident + :name: Save -Forces the name of the original goal to be :n:`@ident`. This -command (and the following ones) can only be used if the original goal -has been opened using the ``Goal`` command. + Forces the name of the original goal to be :token:`ident`. This + command (and the following ones) can only be used if the original goal + has been opened using the :cmd:`Goal` command. +.. cmd:: Admitted -.. cmd:: Admitted. + This command is available in interactive editing mode to give up + the current proof and declare the initial goal as an axiom. -This command is available in interactive editing proof mode to give up -the current proof and declare the initial goal as an axiom. +.. cmd:: Abort + This command cancels the current proof development, switching back to + the previous proof development, or to the |Coq| toplevel if no other + proof was edited. -.. cmd:: Proof @term. + .. exn:: No focused proof (No proof-editing in progress). -This command applies in proof editing mode. It is equivalent to + .. cmdv:: Abort @ident -.. cmd:: exact @term. Qed. + Aborts the editing of the proof named :token:`ident` (in case you have + nested proofs). -That is, you have to give the full proof in one gulp, as a -proof term (see Section :ref:`applyingtheorems`). + .. seealso:: :opt:`Nested Proofs Allowed` + .. cmdv:: Abort All -.. cmdv:: Proof. + Aborts all current goals. -Is a noop which is useful to delimit the sequence of tactic commands -which start a proof, after a ``Theorem`` command. It is a good practice to -use ``Proof``. as an opening parenthesis, closed in the script with a -closing ``Qed``. +.. cmd:: Proof @term + :name: Proof `term` + This command applies in proof editing mode. It is equivalent to + :n:`exact @term. Qed.` + That is, you have to give the full proof in one gulp, as a + proof term (see Section :ref:`applyingtheorems`). -See also: ``Proof with tactic.`` in Section -:ref:`setimpautotactics`. +.. cmd:: Proof + Is a no-op which is useful to delimit the sequence of tactic commands + which start a proof, after a :cmd:`Theorem` command. It is a good practice to + use :cmd:`Proof` as an opening parenthesis, closed in the script with a + closing :cmd:`Qed`. -.. cmd:: Proof using @ident1 ... @identn. + .. seealso:: :cmd:`Proof with` -This command applies in proof editing mode. It declares the set of -section variables (see :ref:`TODO-gallina-assumptions`) used by the proof. At ``Qed`` time, the -system will assert that the set of section variables actually used in -the proof is a subset of the declared one. +.. cmd:: Proof using {+ @ident } -The set of declared variables is closed under type dependency. For -example if ``T`` is variable and a is a variable of type ``T``, the commands -``Proof using a`` and ``Proof using T a``` are actually equivalent. + This command applies in proof editing mode. It declares the set of + section variables (see :ref:`gallina-assumptions`) used by the proof. + At :cmd:`Qed` time, the + system will assert that the set of section variables actually used in + the proof is a subset of the declared one. + The set of declared variables is closed under type dependency. For + example if ``T`` is variable and a is a variable of type ``T``, the commands + ``Proof using a`` and ``Proof using T a`` are actually equivalent. -.. cmdv:: Proof using @ident1 ... @identn with @tactic. + .. cmdv:: Proof using {+ @ident } with @tactic -in Section :ref:`setimpautotactics`. + Combines in a single line :cmd:`Proof with` and :cmd:`Proof using`. -.. cmdv:: Proof using All. + .. seealso:: :ref:`tactics-implicit-automation` -Use all section variables. + .. cmdv:: Proof using All + Use all section variables. -.. cmdv:: Proof using Type. + .. cmdv:: Proof using {? Type } -.. cmdv:: Proof using. + Use only section variables occurring in the statement. -Use only section variables occurring in the statement. + .. cmdv:: Proof using Type* + The ``*`` operator computes the forward transitive closure. E.g. if the + variable ``H`` has type ``p < 5`` then ``H`` is in ``p*`` since ``p`` occurs in the type + of ``H``. ``Type*`` is the forward transitive closure of the entire set of + section variables occurring in the statement. -.. cmdv:: Proof using Type*. + .. cmdv:: Proof using -({+ @ident }) -The ``*`` operator computes the forward transitive closure. E.g. if the -variable ``H`` has type ``p < 5`` then ``H`` is in ``p*`` since ``p`` occurs in the type -of ``H``. ``Type*`` is the forward transitive closure of the entire set of -section variables occurring in the statement. + Use all section variables except the list of :token:`ident`. + .. cmdv:: Proof using @collection1 + @collection2 -.. cmdv:: Proof using -(@ident1 ... @identn). + Use section variables from the union of both collections. + See :ref:`nameaset` to know how to form a named collection. -Use all section variables except :n:`@ident1` ... :n:`@identn`. + .. cmdv:: Proof using @collection1 - @collection2 + Use section variables which are in the first collection but not in the + second one. -.. cmdv:: Proof using @collection1 + @collection2 . + .. cmdv:: Proof using @collection - ({+ @ident }) + Use section variables which are in the first collection but not in the + list of :token:`ident`. -.. cmdv:: Proof using @collection1 - @collection2 . + .. cmdv:: Proof using @collection * - -.. cmdv:: Proof using @collection - ( @ident1 ... @identn ). - - -.. cmdv:: Proof using @collection * . - -Use section variables being, respectively, in the set union, set -difference, set complement, set forward transitive closure. See -Section :ref:`nameaset` to know how to form a named collection. The ``*`` operator -binds stronger than ``+`` and ``-``. + Use section variables in the forward transitive closure of the collection. + The ``*`` operator binds stronger than ``+`` and ``-``. Proof using options @@ -186,176 +200,151 @@ Proof using options The following options modify the behavior of ``Proof using``. -.. cmdv:: Set Default Proof Using "@expression". +.. opt:: Default Proof Using "@expression" -Use :n:`@expression` as the default ``Proof``` using value. E.g. ``Set Default -Proof Using "a b"``. will complete all ``Proof`` commands not followed by a -using part with using ``a`` ``b``. + Use :n:`@expression` as the default ``Proof using`` value. E.g. ``Set Default + Proof Using "a b"`` will complete all ``Proof`` commands not followed by a + ``using`` part with ``using a b``. -.. cmdv:: Set Suggest Proof Using. +.. opt:: Suggest Proof Using -When ``Qed`` is performed, suggest a using annotation if the user did not -provide one. + When :cmd:`Qed` is performed, suggest a ``using`` annotation if the user did not + provide one. .. _`nameaset`: Name a set of section hypotheses for ``Proof using`` ```````````````````````````````````````````````````` -The command ``Collection`` can be used to name a set of section -hypotheses, with the purpose of making ``Proof using`` annotations more -compact. - - -.. cmdv:: Collection Some := x y z. - -Define the collection named "Some" containing ``x``, ``y`` and ``z``. - - -.. cmdv:: Collection Fewer := Some - z. - -Define the collection named "Fewer" containing only ``x`` and ``y``. - - -.. cmdv:: Collection Many := Fewer + Some. -.. cmdv:: Collection Many := Fewer - Some. - -Define the collection named "Many" containing the set union or set -difference of "Fewer" and "Some". - - -.. cmdv:: Collection Many := Fewer - (x y). +.. cmd:: Collection @ident := @expression -Define the collection named "Many" containing the set difference of -"Fewer" and the unnamed collection ``x`` ``y``. + This can be used to name a set of section + hypotheses, with the purpose of making ``Proof using`` annotations more + compact. + .. example:: -.. cmd:: Abort. + Define the collection named ``Some`` containing ``x``, ``y`` and ``z``:: -This command cancels the current proof development, switching back to -the previous proof development, or to the |Coq| toplevel if no other -proof was edited. + Collection Some := x y z. + Define the collection named ``Fewer`` containing only ``x`` and ``y``:: -.. exn:: No focused proof (No proof-editing in progress) + Collection Fewer := Some - z + Define the collection named ``Many`` containing the set union or set + difference of ``Fewer`` and ``Some``:: + Collection Many := Fewer + Some + Collection Many := Fewer - Some -.. cmdv:: Abort @ident. + Define the collection named ``Many`` containing the set difference of + ``Fewer`` and the unnamed collection ``x y``:: -Aborts the editing of the proof named :n:`@ident`. + Collection Many := Fewer - (x y) -.. cmdv:: Abort All. -Aborts all current goals, switching back to the |Coq| -toplevel. +.. cmd:: Existential @num := @term + This command instantiates an existential variable. :token:`num` is an index in + the list of uninstantiated existential variables displayed by :cmd:`Show Existentials`. -.. cmd:: Existential @num := @term. + This command is intended to be used to instantiate existential + variables when the proof is completed but some uninstantiated + existential variables remain. To instantiate existential variables + during proof edition, you should use the tactic :tacn:`instantiate`. -This command instantiates an existential variable. :n:`@num` is an index in -the list of uninstantiated existential variables displayed by ``Show -Existentials`` (described in Section :ref:`requestinginformation`). +.. cmd:: Grab Existential Variables -This command is intended to be used to instantiate existential -variables when the proof is completed but some uninstantiated -existential variables remain. To instantiate existential variables -during proof edition, you should use the tactic instantiate. - - -See also: ``instantiate (num:= term).`` in Section -:ref:`TODO-controllingtheproofflow`. -See also: ``Grab Existential Variables.`` below. - - -.. cmd:: Grab Existential Variables. - -This command can be run when a proof has no more goal to be solved but -has remaining uninstantiated existential variables. It takes every -uninstantiated existential variable and turns it into a goal. + This command can be run when a proof has no more goal to be solved but + has remaining uninstantiated existential variables. It takes every + uninstantiated existential variable and turns it into a goal. Navigation in the proof tree -------------------------------- +.. cmd:: Undo -.. cmd:: Undo. - -This command cancels the effect of the last command. Thus, it -backtracks one step. + This command cancels the effect of the last command. Thus, it + backtracks one step. +.. cmdv:: Undo @num -.. cmdv:: Undo @num. + Repeats Undo :token:`num` times. -Repeats Undo :n:`@num` times. +.. cmdv:: Restart + :name: Restart -.. cmdv:: Restart. + This command restores the proof editing process to the original goal. -This command restores the proof editing process to the original goal. + .. exn:: No focused proof to restart. +.. cmd:: Focus -.. exn:: No focused proof to restart + This focuses the attention on the first subgoal to prove and the + printing of the other subgoals is suspended until the focused subgoal + is solved or unfocused. This is useful when there are many current + subgoals which clutter your screen. + .. deprecated:: 8.8 -.. cmd:: Focus. + Prefer the use of bullets or focusing brackets (see below). -This focuses the attention on the first subgoal to prove and the -printing of the other subgoals is suspended until the focused subgoal -is solved or unfocused. This is useful when there are many current -subgoals which clutter your screen. +.. cmdv:: Focus @num + This focuses the attention on the :token:`num` th subgoal to prove. -.. cmdv:: Focus @num. + .. deprecated:: 8.8 -This focuses the attention on the :n:`@num` th subgoal to -prove. + Prefer the use of focusing brackets with a goal selector (see below). -*This command is deprecated since 8.8*: prefer the use of bullets or -focusing brackets instead, including :n:`@num : %{` +.. cmd:: Unfocus -.. cmd:: Unfocus. + This command restores to focus the goal that were suspended by the + last :cmd:`Focus` command. -This command restores to focus the goal that were suspended by the -last ``Focus`` command. + .. deprecated:: 8.8 -*This command is deprecated since 8.8.* +.. cmd:: Unfocused -.. cmd:: Unfocused. - -Succeeds if the proof is fully unfocused, fails is there are some -goals out of focus. + Succeeds if the proof is fully unfocused, fails if there are some + goals out of focus. +.. _curly-braces: .. cmd:: %{ %| %} -The command ``{`` (without a terminating period) focuses on the first -goal, much like ``Focus.`` does, however, the subproof can only be -unfocused when it has been fully solved ( *i.e.* when there is no -focused goal left). Unfocusing is then handled by ``}`` (again, without a -terminating period). See also example in next section. + The command ``{`` (without a terminating period) focuses on the first + goal, much like :cmd:`Focus` does, however, the subproof can only be + unfocused when it has been fully solved ( *i.e.* when there is no + focused goal left). Unfocusing is then handled by ``}`` (again, without a + terminating period). See also example in next section. -Note that when a focused goal is proved a message is displayed -together with a suggestion about the right bullet or ``}`` to unfocus it -or focus the next one. + Note that when a focused goal is proved a message is displayed + together with a suggestion about the right bullet or ``}`` to unfocus it + or focus the next one. -.. cmdv:: @num: %{ + .. cmdv:: @num: %{ -This focuses on the :n:`@num` th subgoal to prove. + This focuses on the :token:`num` th subgoal to prove. -Error messages: + Error messages: -.. exn:: This proof is focused, but cannot be unfocused this way + .. exn:: This proof is focused, but cannot be unfocused this way. -You are trying to use ``}`` but the current subproof has not been fully solved. + You are trying to use ``}`` but the current subproof has not been fully solved. -.. exn:: No such goal + .. exn:: No such goal. + :name: No such goal. (Focusing) -.. exn:: Brackets only support the single numbered goal selector + .. exn:: Brackets only support the single numbered goal selector. + See also error messages about bullets below. -See also error messages about bullets below. +.. _bullets: Bullets ``````` @@ -404,171 +393,185 @@ The following example script illustrates all these features: assumption. -.. exn:: Wrong bullet @bullet1 : Current bullet @bullet2 is not finished. +.. exn:: Wrong bullet @bullet1: Current bullet @bullet2 is not finished. -Before using bullet :n:`@bullet1` again, you should first finish proving the current focused goal. Note that :n:`@bullet1` and :n:`@bullet2` may be the same. + Before using bullet :n:`@bullet1` again, you should first finish proving the current focused goal. Note that :n:`@bullet1` and :n:`@bullet2` may be the same. -.. exn:: Wrong bullet @bullet1 : Bullet @bullet2 is mandatory here. +.. exn:: Wrong bullet @bullet1: Bullet @bullet2 is mandatory here. -You must put :n:`@bullet2` to focus next goal. No other bullet is allowed here. + You must put :n:`@bullet2` to focus next goal. No other bullet is allowed here. .. exn:: No such goal. Focus next goal with bullet @bullet. -You tried to applied a tactic but no goal where under focus. Using :n:`@bullet` is mandatory here. + You tried to apply a tactic but no goal where under focus. Using :n:`@bullet` is mandatory here. .. exn:: No such goal. Try unfocusing with %{. -You just finished a goal focused by ``{``, you must unfocus it with ``}``. + You just finished a goal focused by ``{``, you must unfocus it with ``}``. Set Bullet Behavior ``````````````````` +.. opt:: Bullet Behavior %( "None" %| "Strict Subproofs" %) -The bullet behavior can be controlled by the following commands. - -.. opt:: Bullet Behavior "None". - -This makes bullets inactive. - -.. opt:: Bullet Behavior "Strict Subproofs". - -This makes bullets active (this is the default behavior). + This option controls the bullet behavior and can take two possible values: + - "None": this makes bullets inactive. + - "Strict Subproofs": this makes bullets active (this is the default behavior). +.. _requestinginformation: Requesting information ---------------------- -.. cmd:: Show. +.. cmd:: Show -This command displays the current goals. + This command displays the current goals. + .. exn:: No focused proof. -.. cmdv:: Show @num + .. cmdv:: Show @num -Displays only the :n:`@num`-th subgoal. + Displays only the :token:`num` th subgoal. -.. exn:: No such goal -.. exn:: No focused proof + .. exn:: No such goal. -.. cmdv:: Show @ident. -Displays the named goal :n:`@ident`. This is useful in -particular to display a shelved goal but only works if the -corresponding existential variable has been named by the user -(see :ref:`exvariables`) as in the following example. + .. cmdv:: Show @ident -.. example:: + Displays the named goal :token:`ident`. This is useful in + particular to display a shelved goal but only works if the + corresponding existential variable has been named by the user + (see :ref:`existential-variables`) as in the following example. - .. coqtop:: all + .. example:: - Goal exists n, n = 0. - eexists ?[n]. - Show n. + .. coqtop:: all -.. cmdv:: Show Script. + Goal exists n, n = 0. + eexists ?[n]. + Show n. -Displays the whole list of tactics applied from the -beginning of the current proof. This tactics script may contain some -holes (subgoals not yet proved). They are printed under the form + .. cmdv:: Show Script + :name: Show Script -``<Your Tactic Text here>``. + Displays the whole list of tactics applied from the + beginning of the current proof. This tactics script may contain some + holes (subgoals not yet proved). They are printed under the form -.. cmdv:: Show Proof. + ``<Your Tactic Text here>``. -It displays the proof term generated by the tactics -that have been applied. If the proof is not completed, this term -contain holes, which correspond to the sub-terms which are still to be -constructed. These holes appear as a question mark indexed by an -integer, and applied to the list of variables in the context, since it -may depend on them. The types obtained by abstracting away the context -from the type of each hole-placer are also printed. + .. cmdv:: Show Proof + :name: Show Proof -.. cmdv:: Show Conjectures. + It displays the proof term generated by the tactics + that have been applied. If the proof is not completed, this term + contain holes, which correspond to the sub-terms which are still to be + constructed. These holes appear as a question mark indexed by an + integer, and applied to the list of variables in the context, since it + may depend on them. The types obtained by abstracting away the context + from the type of each hole-placer are also printed. -It prints the list of the names of all the -theorems that are currently being proved. As it is possible to start -proving a previous lemma during the proof of a theorem, this list may -contain several names. + .. cmdv:: Show Conjectures + :name: Show Conjectures -.. cmdv:: Show Intro. + It prints the list of the names of all the + theorems that are currently being proved. As it is possible to start + proving a previous lemma during the proof of a theorem, this list may + contain several names. -If the current goal begins by at least one product, -this command prints the name of the first product, as it would be -generated by an anonymous ``intro``. The aim of this command is to ease -the writing of more robust scripts. For example, with an appropriate -Proof General macro, it is possible to transform any anonymous ``intro`` -into a qualified one such as ``intro y13``. In the case of a non-product -goal, it prints nothing. + .. cmdv:: Show Intro + :name: Show Intro -.. cmdv:: Show Intros. + If the current goal begins by at least one product, + this command prints the name of the first product, as it would be + generated by an anonymous :tacn:`intro`. The aim of this command is to ease + the writing of more robust scripts. For example, with an appropriate + Proof General macro, it is possible to transform any anonymous :tacn:`intro` + into a qualified one such as ``intro y13``. In the case of a non-product + goal, it prints nothing. -This command is similar to the previous one, it -simulates the naming process of an intros. + .. cmdv:: Show Intros + :name: Show Intros -.. cmdv:: Show Existentials. + This command is similar to the previous one, it + simulates the naming process of an :tacn:`intros`. -It displays the set of all uninstantiated -existential variables in the current proof tree, along with the type -and the context of each variable. + .. cmdv:: Show Existentials + :name: Show Existentials -.. cmdv:: Show Match @ident. + It displays the set of all uninstantiated + existential variables in the current proof tree, along with the type + and the context of each variable. -This variant displays a template of the Gallina -``match`` construct with a branch for each constructor of the type -:n:`@ident` + .. cmdv:: Show Match @ident -.. example:: - .. coqtop:: all + This variant displays a template of the Gallina + ``match`` construct with a branch for each constructor of the type + :token:`ident` + + .. example:: + .. coqtop:: all - Show Match nat. + Show Match nat. -.. exn:: Unknown inductive type + .. exn:: Unknown inductive type. -.. exn:: Show Universes. + .. cmdv:: Show Universes + :name: Show Universes -It displays the set of all universe constraints and -its normalized form at the current stage of the proof, useful for -debugging universe inconsistencies. + It displays the set of all universe constraints and + its normalized form at the current stage of the proof, useful for + debugging universe inconsistencies. -.. cmd:: Guarded. +.. cmd:: Guarded -Some tactics (e.g. refine :ref:`applyingtheorems`) allow to build proofs using -fixpoint or co-fixpoint constructions. Due to the incremental nature -of interactive proof construction, the check of the termination (or -guardedness) of the recursive calls in the fixpoint or cofixpoint -constructions is postponed to the time of the completion of the proof. + Some tactics (e.g. :tacn:`refine`) allow to build proofs using + fixpoint or co-fixpoint constructions. Due to the incremental nature + of interactive proof construction, the check of the termination (or + guardedness) of the recursive calls in the fixpoint or cofixpoint + constructions is postponed to the time of the completion of the proof. -The command ``Guarded`` allows checking if the guard condition for -fixpoint and cofixpoint is violated at some time of the construction -of the proof without having to wait the completion of the proof. + The command :cmd:`Guarded` allows checking if the guard condition for + fixpoint and cofixpoint is violated at some time of the construction + of the proof without having to wait the completion of the proof. Controlling the effect of proof editing commands ------------------------------------------------ -.. opt:: Hyps Limit @num. +.. opt:: Hyps Limit @num + + This option controls the maximum number of hypotheses displayed in goals + after the application of a tactic. All the hypotheses remain usable + in the proof development. + When unset, it goes back to the default mode which is to print all + available hypotheses. + + +.. opt:: Automatic Introduction -This option controls the maximum number of hypotheses displayed in goals -after the application of a tactic. All the hypotheses remain usable -in the proof development. -When unset, it goes back to the default mode which is to print all -available hypotheses. + This option controls the way binders are handled + in assertion commands such as :n:`Theorem @ident {? @binders} : @term`. When the + option is on, which is the default, binders are automatically put in + the local context of the goal to prove. + When the option is off, binders are discharged on the statement to be + proved and a tactic such as :tacn:`intro` (see Section :ref:`managingthelocalcontext`) + has to be used to move the assumptions to the local context. -.. opt:: Automatic Introduction. -This option controls the way binders are handled -in assertion commands such as ``Theorem ident [binders] : form``. When the -option is set, which is the default, binders are automatically put in -the local context of the goal to prove. +.. opt:: Nested Proofs Allowed -The option can be unset by issuing ``Unset Automatic Introduction``. When -the option is unset, binders are discharged on the statement to be -proved and a tactic such as intro (see Section :ref:`managingthelocalcontext`) has to be -used to move the assumptions to the local context. + When turned on (it is off by default), this option enables support for nested + proofs: a new assertion command can be inserted before the current proof is + finished, in which case Coq will temporarily switch to the proof of this + *nested lemma*. When the proof of the nested lemma is finished (with :cmd:`Qed` + or :cmd:`Defined`), its statement will be made available (as if it had been + proved before starting the previous proof) and Coq will switch back to the + proof of the previous assertion. Controlling memory usage @@ -578,15 +581,15 @@ When experiencing high memory usage the following commands can be used to force |Coq| to optimize some of its internal data structures. -.. cmd:: Optimize Proof. +.. cmd:: Optimize Proof -This command forces |Coq| to shrink the data structure used to represent -the ongoing proof. + This command forces |Coq| to shrink the data structure used to represent + the ongoing proof. -.. cmd:: Optimize Heap. +.. cmd:: Optimize Heap -This command forces the |OCaml| runtime to perform a heap compaction. -This is in general an expensive operation. -See: `OCaml Gc <http://caml.inria.fr/pub/docs/manual-ocaml/libref/Gc.html#VALcompact>`_ -There is also an analogous tactic ``optimize_heap`` (see~:ref:`tactic-optimizeheap`) + This command forces the |OCaml| runtime to perform a heap compaction. + This is in general an expensive operation. + See: `OCaml Gc <http://caml.inria.fr/pub/docs/manual-ocaml/libref/Gc.html#VALcompact>`_ + There is also an analogous tactic :tacn:`optimize_heap`. diff --git a/doc/sphinx/proof-engine/ssreflect-proof-language.rst b/doc/sphinx/proof-engine/ssreflect-proof-language.rst index 61dffa0243..63cd0f3ead 100644 --- a/doc/sphinx/proof-engine/ssreflect-proof-language.rst +++ b/doc/sphinx/proof-engine/ssreflect-proof-language.rst @@ -6,10 +6,7 @@ The |SSR| proof language ------------------------------ -:Source: https://coq.inria.fr/distrib/current/refman/ssreflect.html -:Converted by: Enrico Tassi - -Author: Georges Gonthier, Assia Mahboubi, Enrico Tassi +:Authors: Georges Gonthier, Assia Mahboubi, Enrico Tassi Introduction @@ -426,7 +423,7 @@ an improvement over ``all null s``. The syntax of the new declaration is -.. cmd:: Prenex Implicits {+ @ident}. +.. cmd:: Prenex Implicits {+ @ident} Let us denote :math:`c_1` … :math:`c_n` the list of identifiers given to a ``Prenex Implicits`` command. The command checks that each ci is the name of @@ -451,7 +448,7 @@ Anonymous arguments ~~~~~~~~~~~~~~~~~~~ When in a definition, the type of a certain argument is mandatory, but -not its name, one usually use “arrow” abstractions for prenex +not its name, one usually uses “arrow” abstractions for prenex arguments, or the ``(_ : term)`` syntax for inner arguments. In |SSR|, the latter can be replaced by the open syntax ``of term`` or (equivalently) ``& term``, which are both syntactically equivalent to a @@ -496,7 +493,10 @@ inferred from the whole context of the goal (see for example section Definitions ~~~~~~~~~~~ -The pose tactic allows to add a defined constant to a proof context. +.. tacn:: pose + :name: pose (ssreflect) + +This tactic allows to add a defined constant to a proof context. |SSR| generalizes this tactic in several ways. In particular, the |SSR| pose tactic supports *open syntax*: the body of the definition does not need surrounding parentheses. For instance: @@ -518,7 +518,7 @@ is a valid tactic expression. The pose tactic is also improved for the local definition of higher order terms. Local definitions of functions can use the same syntax as -global ones. For example the tactic ``pose`` supoprts parameters: +global ones. For example, the tactic ``pose`` supoprts parameters: .. example:: @@ -1295,7 +1295,7 @@ is a synonym for: intro top; first [refine top | refine (top _) | refine (top _ _) | …]; clear top. -where ``top`` is fresh name, and the sequence of refine tactics tries to +where ``top`` is a fresh name, and the sequence of refine tactics tries to catch the appropriate number of wildcards to be inserted. Note that this use of the refine tactic implies that the tactic tries to match the goal up to expansion of constants and evaluation of subterms. @@ -1352,6 +1352,7 @@ Discharge The general syntax of the discharging tactical ``:`` is: .. tacn:: @tactic {? @ident } : {+ @d_item } {? @clear_switch } + :name: ... : ... (ssreflect) .. prodn:: d_item ::= {? @occ_switch %| @clear_switch } @term @@ -1503,9 +1504,11 @@ side of an equation. The abstract tactic ``````````````````` -The ``abstract`` tactic assigns an ``abstract`` constant previously -introduced with the ``[: name ]`` intro pattern -(see section :ref:`introduction_ssr`). +.. tacn:: abstract: {+ d_item} + :name abstract (ssreflect) + +This tactic assigns an abstract constant previously introduced with the ``[: +name ]`` intro pattern (see section :ref:`introduction_ssr`). In a goal like the following:: @@ -1573,7 +1576,7 @@ The :token:`i_pattern` s can be seen as a variant of *intro patterns* :ref:`tactics`: each performs an introduction operation, i.e., pops some variables or assumptions from the goal. -An :token:`s_item` can simplify the set of subgoals or the subgoal themselves: +An :token:`s_item` can simplify the set of subgoals or the subgoals themselves: + ``//`` removes all the “trivial” subgoals that can be resolved by the |SSR| tactic ``done`` described in :ref:`terminators_ssr`, i.e., @@ -1812,6 +1815,8 @@ of a :token:`d_item` immediately following this ``/`` switch, using the syntax: .. tacv:: case: {+ @d_item } / {+ @d_item } + :name: case (ssreflect) + .. tacv:: elim: {+ @d_item } / {+ @d_item } The :token:`d_item` on the right side of the ``/`` switch are discharged as @@ -1831,7 +1836,7 @@ compact syntax: case: {2}_ / eqP. -were ``_`` is interpreted as ``(_ == _)`` since +where ``_`` is interpreted as ``(_ == _)`` since ``eqP T a b : reflect (a = b) (a == b)`` and reflect is a type family with one index. @@ -2074,7 +2079,7 @@ is equivalent to: do [done | by move=> top; apply top]. -where top is a fresh name affected to the top assumption of the goal. +where ``top`` is a fresh name assigned to the top assumption of the goal. This applied form is supported by the : discharge tactical, and the tactic: @@ -2090,7 +2095,7 @@ is equivalent to: (see section :ref:`discharge_ssr` for the documentation of the apply: combination). -Warning The list of tactics, possibly chained by semi-columns, that +Warning The list of tactics, possibly chained by semicolons, that follows a by keyword is considered as a parenthesized block applied to the current goal. Hence for example if the tactic: @@ -2123,7 +2128,7 @@ generated by the previous tactic. This covers the frequent cases where a tactic generates two subgoals one of which can be easily disposed of. -This is an other powerful way of linearization of scripts, since it +This is another powerful way of linearization of scripts, since it happens very often that a trivial subgoal can be solved in a less than one line tactic. For instance, the tactic: @@ -2131,14 +2136,14 @@ one line tactic. For instance, the tactic: :name: last tries to solve the last subgoal generated by the first -tactic using the given second tactic , and fails if it does not succeeds. -Its analogous +tactic using the given second tactic, and fails if it does not succeed. +Its analogue .. tacn:: @tactic ; first by @tactic - :name: first + :name: first (ssreflect) tries to solve the first subgoal generated by the first tactic using the -second given tactic, and fails if it does not succeeds. +second given tactic, and fails if it does not succeed. |SSR| also offers an extension of this facility, by supplying tactics to *permute* the subgoals generated by a tactic. The tactic: @@ -2152,10 +2157,10 @@ equivalent to: More generally, the tactic: -.. tacn:: @tactic; last @natural first +.. tacn:: @tactic; last @num first :name: last first -where :token:`natural` is a |Coq| numeral, or and Ltac variable +where :token:`num` is a |Coq| numeral, or an Ltac variable denoting a |Coq| numeral, having the value k. It rotates the n subgoals G1 , …, Gn generated by tactic. The first subgoal becomes Gn + 1 − k and the @@ -2163,7 +2168,7 @@ circular order of subgoals remains unchanged. Conversely, the tactic: -.. tacn:: @tactic; first @natural last +.. tacn:: @tactic; first @num last :name: first last rotates the n subgoals G1 , …, Gn generated by tactic in order that @@ -2215,7 +2220,7 @@ Iteration thanks to the do tactical, whose general syntax is: .. tacn:: do {? @mult } ( @tactic | [ {+| @tactic } ] ) - :name: do + :name: do (ssreflect) where :token:`mult` is a *multiplier*. @@ -2259,14 +2264,14 @@ For instance, the tactic: tactic; do 1? rewrite mult_comm. -rewrites at most one time the lemma ``mult_com`` in all the subgoals +rewrites at most one time the lemma ``mult_comm`` in all the subgoals generated by tactic , whereas the tactic: .. coqtop:: in tactic; do 2! rewrite mult_comm. -rewrites exactly two times the lemma ``mult_com`` in all the subgoals +rewrites exactly two times the lemma ``mult_comm`` in all the subgoals generated by tactic, and fails if this rewrite is not possible in some subgoal. @@ -2335,10 +2340,10 @@ to the following one: .. tacv:: @tactic in {+ @clear_switch | {? @ } @ident | ( @ident ) | ( {? @ } @ident := @c_pattern ) } {? * } In its simplest form the last option lets one rename hypotheses that -can’t be cleared (like section variables). For example ``(y := x)`` +can’t be cleared (like section variables). For example, ``(y := x)`` generalizes over ``x`` and reintroduces the generalized variable under the name ``y`` (and does not clear ``x``). -For a more precise description this form of localization refer +For a more precise description of this form of localization refer to :ref:`advanced_generalization_ssr`. @@ -2351,7 +2356,7 @@ Forward reasoning structures the script by explicitly specifying some assumptions to be added to the proof context. It is closely associated with the declarative style of proof, since an extensive use of these highlighted statements make the script closer to a (very detailed) -text book proof. +textbook proof. Forward chaining tactics allow to state an intermediate lemma and start a piece of script dedicated to the proof of this statement. The use of closing @@ -2492,7 +2497,7 @@ also supported (assuming x occurs in the goal only): have {x} -> : x = y. -An other frequent use of the intro patterns combined with ``have`` is the +Another frequent use of the intro patterns combined with ``have`` is the destruction of existential assumptions like in the tactic: .. example:: @@ -2752,12 +2757,9 @@ type classes inference. No inference for ``t``. Unresolved instances are quantified in the (inferred) type of ``t`` and abstracted in ``t``. +.. opt:: SsrHave NoTCResolution -The behavior of |SSR| 1.4 and below (never resolve type classes) -can be restored with the option - -.. cmd:: Set SsrHave NoTCResolution. - + This option restores the behavior of |SSR| 1.4 and below (never resolve type classes). Variants: the suff and wlog tactics ``````````````````````````````````` @@ -2845,8 +2847,8 @@ term -> G. If the optional list of :token:`itent` is present on the left side of ``/``, these constants are generalized in the -premise (term -> G) of the first subgoal. By default the body of local -definitions is erased. This behavior can be inhibited prefixing the +premise (term -> G) of the first subgoal. By default bodies of local +definitions are erased. This behavior can be inhibited by prefixing the name of the local definition with the ``@`` character. In the second subgoal, the tactic: @@ -2936,7 +2938,7 @@ renaming does not require the original variable to be cleared. The syntax ``(@x := y)`` generates a let-in abstraction but with the following caveat: ``x`` will not bind ``y``, but its body, whenever ``y`` can be -unfolded. This cover the case of both local and global definitions, as +unfolded. This covers the case of both local and global definitions, as illustrated in the following example. .. example:: @@ -3035,7 +3037,7 @@ operation should be performed: specifies if and how the rewrite operation should be repeated. + A rewrite operation matches the occurrences of a *rewrite pattern*, - and replaces these occurrences by an other term, according to the + and replaces these occurrences by another term, according to the given :token:`r_item`. The optional *redex switch* ``[r_pattern]``, which should always be surrounded by brackets, gives explicitly this rewrite @@ -3329,7 +3331,7 @@ The rewrite tactic can be provided a *tuple* of rewrite rules, or more generally a tree of such rules, since this tuple can feature arbitrary inner parentheses. We call *multirule* such a generalized rewrite rule. This feature is of special interest when it is combined with -multiplier switches, which makes the rewrite tactic iterates the +multiplier switches, which makes the rewrite tactic iterate the rewrite operations prescribed by the rules on the current goal. @@ -3473,7 +3475,7 @@ efficient ones, e.g. for the purpose of a correctness proof. Wildcards vs abstractions ````````````````````````` -The rewrite tactic supports :token:`r_items` containing holes. For example in +The rewrite tactic supports :token:`r_items` containing holes. For example, in the tactic ``rewrite (_ : _ * 0 = 0).`` the term ``_ * 0 = 0`` is interpreted as ``forall n : nat, n * 0 = 0.`` Anyway this tactic is *not* equivalent to @@ -3730,14 +3732,15 @@ We provide a special tactic unlock for unfolding such definitions while removing “locks”, e.g., the tactic: .. tacn:: unlock {? @occ_switch } @ident + :name: unlock replaces the occurrence(s) of :token:`ident` coded by the :token:`occ_switch` with the corresponding body. We found that it was usually preferable to prevent the expansion of some functions by the partial evaluation switch ``/=``, unless this -allowed the evaluation of a condition. This is possible thanks to an -other mechanism of term tagging, resting on the following *Notation*: +allowed the evaluation of a condition. This is possible thanks to another +mechanism of term tagging, resting on the following *Notation*: .. coqtop:: in @@ -3781,7 +3784,7 @@ arithmetic operations. We define for instance: The operation ``addn`` behaves exactly like ``plus``, except that ``(addn (S n) m)`` will not simplify spontaneously to -``(S (addn n m))`` (the two terms, however, are inter-convertible). +``(S (addn n m))`` (the two terms, however, are convertible). In addition, the unfolding step: ``rewrite /addn`` will replace ``addn`` directly with ``plus``, so the ``nosimpl`` form is essentially invisible. @@ -3792,7 +3795,7 @@ essentially invisible. Congruence ~~~~~~~~~~ -Because of the way matching interferes with type families parameters, +Because of the way matching interferes with parameters of type families, the tactic: .. coqtop:: in @@ -3912,8 +3915,8 @@ The simple form of patterns used so far, terms possibly containing wild cards, often require an additional :token:`occ_switch` to be specified. While this may work pretty fine for small goals, the use of polymorphic functions and dependent types may lead to an invisible -duplication of functions arguments. These copies usually end up in -types hidden by the implicit arguments machinery or by user defined +duplication of function arguments. These copies usually end up in +types hidden by the implicit arguments machinery or by user-defined notations. In these situations computing the right occurrence numbers is very tedious because they must be counted on the goal as printed after setting the Printing All flag. Moreover the resulting script is @@ -3981,7 +3984,7 @@ pattern for the redex looking at the rule used for rewriting. The first :token:`c_pattern` is the simplest form matching any context but selecting a specific redex and has been described in the previous sections. We have seen so far that the possibility of selecting a -redex using a term with holes is already a powerful mean of redex +redex using a term with holes is already a powerful means of redex selection. Similarly, any terms provided by the user in the more complex forms of :token:`c_patterns` presented in the tables above can contain @@ -4064,7 +4067,7 @@ Contextual pattern in set and the : tactical As already mentioned in section :ref:`abbreviations_ssr` the ``set`` tactic takes as an argument a term in open syntax. This term is interpreted as the -simplest for of :token:`c_pattern`. To void confusion in the grammar, open +simplest form of :token:`c_pattern`. To avoid confusion in the grammar, open syntax is supported only for the simplest form of patterns, while parentheses are required around more complex patterns. @@ -4086,17 +4089,17 @@ parentheses are required around more complex patterns. set t := (a + _ in X in _ = X). -Since the user may define an infix notation for ``in`` the former tactic -may result ambiguous. The disambiguation rule implemented is to prefer +Since the user may define an infix notation for ``in`` the result of the former +tactic may be ambiguous. The disambiguation rule implemented is to prefer patterns over simple terms, but to interpret a pattern with double -parentheses as a simple term. For example the following tactic would +parentheses as a simple term. For example, the following tactic would capture any occurrence of the term ``a in A``. .. coqtop:: in set t := ((a in A)). -Contextual pattern can also be used as arguments of the ``:`` tactical. +Contextual patterns can also be used as arguments of the ``:`` tactical. For example: .. coqtop:: in @@ -4139,7 +4142,7 @@ Contextual patterns in rewrite Note that the right hand side of ``addn0`` is undetermined, but the rewrite pattern specifies the redex explicitly. The right hand side - of ``addn0`` is unified with the term identified by ``X``, ``0`` here. + of ``addn0`` is unified with the term identified by ``X``, here ``0``. The following pattern does not specify a redex, since it identifies an @@ -4269,7 +4272,7 @@ generation (see section :ref:`generation_of_equations_ssr`). .. example:: - The following script illustrate a toy example of this feature. Let us + The following script illustrates a toy example of this feature. Let us define a function adding an element at the end of a list: .. coqtop:: reset @@ -4283,7 +4286,7 @@ generation (see section :ref:`generation_of_equations_ssr`). .. coqtop:: all Variable d : Type. - Fixpoint add_last(s : list d) (z : d) {struct s} : list d := + Fixpoint add_last (s : list d) (z : d) {struct s} : list d := if s is cons x s' then cons x (add_last s' z) else z :: nil. One can define an alternative, reversed, induction principle on @@ -4296,7 +4299,7 @@ generation (see section :ref:`generation_of_equations_ssr`). forall s : list d, P s. Then the combination of elimination views with equation names result - in a concise syntax for reasoning inductively using the user defined + in a concise syntax for reasoning inductively using the user-defined elimination scheme. .. coqtop:: all @@ -4305,8 +4308,8 @@ generation (see section :ref:`generation_of_equations_ssr`). elim/last_ind_list E : l=> [| u v]; last first. -User provided eliminators (potentially generated with the ``Function`` -|Coq|’s command) can be combined with the type family switches described +User-provided eliminators (potentially generated with |Coq|’s ``Function`` +command) can be combined with the type family switches described in section :ref:`type_families_ssr`. Consider an eliminator ``foo_ind`` of type: @@ -4341,7 +4344,7 @@ The ``elim/`` tactic distinguishes two cases: As explained in section :ref:`type_families_ssr`, the initial prefix of ``ei`` can be omitted. -Here an example of a regular, but non trivial, eliminator. +Here is an example of a regular, but nontrivial, eliminator. .. example:: @@ -4423,7 +4426,7 @@ Here an example of a regular, but non trivial, eliminator. ``P`` should be the same as the second argument of ``plus``, in the second argument of ``P``, but ``y`` and ``z`` do no unify. -Here an example of a truncated eliminator: +Here is an example of a truncated eliminator: .. example:: @@ -4481,7 +4484,7 @@ Interpreting assumptions ~~~~~~~~~~~~~~~~~~~~~~~~ Interpreting an assumption in the context of a proof consists in -applying it a lemma before generalizing, and/or decomposing this +applying to it a lemma before generalizing, and/or decomposing this assumption. For instance, with the extensive use of boolean reflection (see section :ref:`views_and_reflection_ssr`.4), it is quite frequent to need to decompose the logical interpretation of (the boolean @@ -4689,7 +4692,7 @@ the bookkeeping tactical ``=>`` since this would be redundant with the Boolean reflection ~~~~~~~~~~~~~~~~~~ -In the Calculus of Inductive Construction, there is an obvious +In the Calculus of Inductive Constructions, there is an obvious distinction between logical propositions and boolean values. On the one hand, logical propositions are objects of *sort* ``Prop`` which is the carrier of intuitionistic reasoning. Logical connectives in @@ -5002,7 +5005,7 @@ but they also allow complex transformation, involving negations. Note that views, being part of :token:`i_pattern`, can be used to interpret assertions too. For example the following script asserts ``a && b`` but -actually used its propositional interpretation. +actually uses its propositional interpretation. .. example:: @@ -5038,7 +5041,7 @@ applied to a goal ``top`` is interpreted in the following way: Like assumption interpretation view hints, goal interpretation ones -are user defined lemmas stored (see section :ref:`views_and_reflection_ssr`) in the ``Hint View`` +are user-defined lemmas stored (see section :ref:`views_and_reflection_ssr`) in the ``Hint View`` database bridging the possible gap between the type of ``term`` and the type of the goal. @@ -5132,7 +5135,7 @@ See the files ``ssreflect.v`` and ``ssrbool.v`` for examples. Multiple views ~~~~~~~~~~~~~~ -The hypotheses and the goal can be interpreted applying multiple views +The hypotheses and the goal can be interpreted by applying multiple views in sequence. Both move and apply can be followed by an arbitrary number of ``/term``. The main difference between the following two tactics @@ -5188,8 +5191,9 @@ equivalences are indeed taken into account, otherwise only single |SSR| proposes an extension of the Search command. Its syntax is: .. cmd:: Search {? @pattern } {* {? - } %( @string %| @pattern %) {? % @ident} } {? in {+ {? - } @qualid } } + :name: Search (ssreflect) -where :token:`qualid` is the name of an open module. This command search returns +where :token:`qualid` is the name of an open module. This command returns the list of lemmas: @@ -5214,7 +5218,7 @@ Note that: + As for regular terms, patterns can feature scope indications. For instance, the command: ``Search _ (_ + _)%N.`` lists all the lemmas whose - statement (conclusion or hypotheses) involve an application of the + statement (conclusion or hypotheses) involves an application of the binary operation denoted by the infix ``+`` symbol in the ``N`` scope (which is |SSR| scope for natural numbers). + Patterns with holes should be surrounded by parentheses. @@ -5318,11 +5322,11 @@ intro item see :ref:`introduction_ssr` multiplier see :ref:`iteration_ssr` -.. prodn:: occ_switch ::= { {? + %| - } {* @natural } } +.. prodn:: occ_switch ::= { {? + %| - } {* @num } } occur. switch see :ref:`occurrence_selection_ssr` -.. prodn:: mult ::= {? @natural } @mult_mark +.. prodn:: mult ::= {? @num } @mult_mark multiplier see :ref:`iteration_ssr` @@ -5491,7 +5495,7 @@ prenex implicits declaration see :ref:`parametric_polymorphism_ssr` used for such generated names. .. [#7] More precisely, it should have a quantified inductive type with a assumptions and m − a constructors. -.. [#8] This is an implementation feature: there is not such obstruction +.. [#8] This is an implementation feature: there is no such obstruction in the metatheory .. [#9] The current state of the proof shall be displayed by the Show Proof command of |Coq| proof mode. diff --git a/doc/sphinx/proof-engine/tactics.rst b/doc/sphinx/proof-engine/tactics.rst index 2af73c28e5..051c28f910 100644 --- a/doc/sphinx/proof-engine/tactics.rst +++ b/doc/sphinx/proof-engine/tactics.rst @@ -24,7 +24,7 @@ Each (sub)goal is denoted with a number. The current goal is numbered 1. By default, a tactic is applied to the current goal, but one can address a particular goal in the list by writing n:tactic which means “apply tactic tactic to goal number n”. We can show the list of -subgoals by typing Show (see Section :ref:`TODO-7.3.1-Show`). +subgoals by typing Show (see Section :ref:`requestinginformation`). Since not every rule applies to a given statement, every tactic cannot be used to reduce any goal. In other words, before applying a tactic @@ -34,15 +34,16 @@ satisfied. If it is not the case, the tactic raises an error message. Tactics are built from atomic tactics and tactic expressions (which extends the folklore notion of tactical) to combine those atomic tactics. This chapter is devoted to atomic tactics. The tactic -language will be described in Chapter :ref:`TODO-9-Thetacticlanguage`. +language will be described in Chapter :ref:`ltac`. + +.. _invocation-of-tactics: Invocation of tactics ------------------------- A tactic is applied as an ordinary command. It may be preceded by a -goal selector (see Section :ref:`TODO-9.2-Semantics`). If no selector is -specified, the default selector (see Section -:ref:`TODO-8.1.1-Setdefaultgoalselector`) is used. +goal selector (see Section :ref:`ltac-semantics`). If no selector is +specified, the default selector is used. .. _tactic_invocation_grammar: @@ -50,20 +51,22 @@ specified, the default selector (see Section tactic_invocation : toplevel_selector : tactic. : |tactic . -.. cmd:: Set Default Goal Selector @toplevel_selector. +.. opt:: Default Goal Selector @toplevel_selector + + This option controls the default selector, used when no selector is + specified when applying a tactic. The initial value is 1, hence the + tactics are, by default, applied to the first goal. -After using this command, the default selector – used when no selector -is specified when applying a tactic – is set to the chosen value. The -initial value is 1, hence the tactics are, by default, applied to the -first goal. Using Set Default Goal Selector ‘‘all’’ will make is so -that tactics are, by default, applied to every goal simultaneously. -Then, to apply a tactic tac to the first goal only, you can write -1:tac. Although more selectors are available, only ‘‘all’’ or a single -natural number are valid default goal selectors. + Using value ``all`` will make it so that tactics are, by default, + applied to every goal simultaneously. Then, to apply a tactic tac + to the first goal only, you can write ``1:tac``. -.. cmd:: Test Default Goal Selector. + Using value ``!`` enforces that all tactics are used either on a + single focused goal or with a local selector (’’strict focusing + mode’’). -This command displays the current default selector. + Although more selectors are available, only ``all``, ``!`` or a + single natural number are valid default goal selectors. .. _bindingslist: @@ -89,14 +92,14 @@ bindings_list`` where ``bindings_list`` may be of two different forms: the ``n``-th non dependent premise of the ``term``, as determined by the type of ``term``. - .. exn:: No such binder + .. exn:: No such binder. + A bindings list can also be a simple list of terms :n:`{* term}`. In that case the references to which these terms correspond are - determined by the tactic. In case of ``induction``, ``destruct``, ``elim`` - and ``case`` (see :ref:`TODO-9-Thetacticlanguage`) the terms have to + determined by the tactic. In case of :tacn:`induction`, :tacn:`destruct`, :tacn:`elim` + and :tacn:`case`, the terms have to provide instances for all the dependent products in the type of term while in - the case of ``apply``, or of ``constructor`` and its variants, only instances + the case of :tacn:`apply`, or of :tacn:`constructor` and its variants, only instances for the dependent products that are not bound in the conclusion of the type are required. @@ -122,14 +125,12 @@ following syntax: The role of an occurrence clause is to select a set of occurrences of a term in a goal. In the first case, the :n:`@ident {? at {* num}}` parts indicate that -occurrences have to be selected in the hypotheses named :n:`@ident`. If no numbers -are given for hypothesis :n:`@ident`, then all the occurrences of `term` in the -hypothesis are selected. If numbers are given, they refer to occurrences of -`term` when the term is printed using option ``Set Printing All`` (see -:ref:`TODO-2.9-Printingconstructionsinfull`), counting from left to right. In -particular, occurrences of `term` in implicit arguments (see -:ref:`TODO-2.7-Implicitarguments`) or coercions (see :ref:`TODO-2.8-Coercions`) -are counted. +occurrences have to be selected in the hypotheses named :n:`@ident`. If no +numbers are given for hypothesis :n:`@ident`, then all the occurrences of `term` +in the hypothesis are selected. If numbers are given, they refer to occurrences +of `term` when the term is printed using option :opt:`Printing All`, counting +from left to right. In particular, occurrences of `term` in implicit arguments +(see :ref:`ImplicitArguments`) or coercions (see :ref:`Coercions`) are counted. If a minus sign is given between at and the list of occurrences, it negates the condition so that the clause denotes all the occurrences @@ -150,14 +151,15 @@ no numbers are given, all occurrences of :n:`@term` in the goal are selected. Finally, the last notation is an abbreviation for ``* |- *``. Note also that ``|-`` is optional in the first case when no ``*`` is given. -Here are some tactics that understand occurrences clauses: ``set``, ``remember`` -, ``induction``, ``destruct``. +Here are some tactics that understand occurrences clauses: :tacn:`set`, :tacn:`remember` +, :tacn:`induction`, :tacn:`destruct`. -See also: :ref:`TODO-8.3.7-Managingthelocalcontext`, -:ref:`TODO-8.5.2-Caseanalysisandinduction`, -:ref:`TODO-2.9-Printingconstructionsinfull`. +See also: :ref:`Managingthelocalcontext`, +:ref:`caseanalysisandinduction`, +:ref:`printing_constructions_full`. +.. _applyingtheorems: Applying theorems --------------------- @@ -165,195 +167,203 @@ Applying theorems .. tacn:: exact @term :name: exact -This tactic applies to any goal. It gives directly the exact proof -term of the goal. Let ``T`` be our goal, let ``p`` be a term of type ``U`` then -``exact p`` succeeds iff ``T`` and ``U`` are convertible (see -:ref:`TODO-4.3-Conversionrules`). + This tactic applies to any goal. It gives directly the exact proof + term of the goal. Let ``T`` be our goal, let ``p`` be a term of type ``U`` then + ``exact p`` succeeds iff ``T`` and ``U`` are convertible (see + :ref:`Conversion-rules`). -.. exn:: Not an exact proof. + .. exn:: Not an exact proof. -.. tacv:: eexact @term. + .. tacv:: eexact @term. + :name: eexact -This tactic behaves like exact but is able to handle terms and goals with -meta-variables. + This tactic behaves like exact but is able to handle terms and goals with + meta-variables. .. tacn:: assumption :name: assumption -This tactic looks in the local context for an hypothesis which type is equal to -the goal. If it is the case, the subgoal is proved. Otherwise, it fails. + This tactic looks in the local context for an hypothesis which type is equal to + the goal. If it is the case, the subgoal is proved. Otherwise, it fails. -.. exn:: No such assumption. + .. exn:: No such assumption. -.. tacv:: eassumption + .. tacv:: eassumption + :name: eassumption -This tactic behaves like assumption but is able to handle goals with -meta-variables. + This tactic behaves like assumption but is able to handle goals with + meta-variables. .. tacn:: refine @term :name: refine -This tactic applies to any goal. It behaves like exact with a big -difference: the user can leave some holes (denoted by ``_`` or``(_:type)``) in -the term. refine will generate as many subgoals as there are holes in -the term. The type of holes must be either synthesized by the system -or declared by an explicit cast like ``(_:nat->Prop)``. Any subgoal that -occurs in other subgoals is automatically shelved, as if calling -shelve_unifiable (see Section 8.17.4). This low-level tactic can be -useful to advanced users. + This tactic applies to any goal. It behaves like :tacn:`exact` with a big + difference: the user can leave some holes (denoted by ``_`` or ``(_:type)``) in + the term. :tacn:`refine` will generate as many subgoals as there are holes in + the term. The type of holes must be either synthesized by the system + or declared by an explicit cast like ``(_:nat->Prop)``. Any subgoal that + occurs in other subgoals is automatically shelved, as if calling + :tacn:`shelve_unifiable`. This low-level tactic can be + useful to advanced users. -.. example:: - .. coqtop:: reset all + .. example:: + .. coqtop:: reset all - Inductive Option : Set := - | Fail : Option - | Ok : bool -> Option. + Inductive Option : Set := + | Fail : Option + | Ok : bool -> Option. - Definition get : forall x:Option, x <> Fail -> bool. + Definition get : forall x:Option, x <> Fail -> bool. - refine - (fun x:Option => - match x return x <> Fail -> bool with - | Fail => _ - | Ok b => fun _ => b - end). + refine + (fun x:Option => + match x return x <> Fail -> bool with + | Fail => _ + | Ok b => fun _ => b + end). - intros; absurd (Fail = Fail); trivial. + intros; absurd (Fail = Fail); trivial. - Defined. + Defined. -.. exn:: invalid argument + .. exn:: Invalid argument. - The tactic ``refine`` does not know what to do with the term you gave. + The tactic :tacn:`refine` does not know what to do with the term you gave. -.. exn:: Refine passed ill-formed term + .. exn:: Refine passed ill-formed term. - The term you gave is not a valid proof (not easy to debug in general). This - message may also occur in higher-level tactics that call ``refine`` - internally. + The term you gave is not a valid proof (not easy to debug in general). This + message may also occur in higher-level tactics that call :tacn:`refine` + internally. -.. exn:: Cannot infer a term for this placeholder + .. exn:: Cannot infer a term for this placeholder. + :name: Cannot infer a term for this placeholder. (refine) - There is a hole in the term you gave which type cannot be inferred. Put a - cast around it. + There is a hole in the term you gave whose type cannot be inferred. Put a + cast around it. -.. tacv:: simple refine @term + .. tacv:: simple refine @term + :name: simple refine - This tactic behaves like refine, but it does not shelve any subgoal. It does - not perform any beta-reduction either. + This tactic behaves like refine, but it does not shelve any subgoal. It does + not perform any beta-reduction either. -.. tacv:: notypeclasses refine @term + .. tacv:: notypeclasses refine @term + :name: notypeclasses refine - This tactic behaves like ``refine`` except it performs typechecking without - resolution of typeclasses. + This tactic behaves like :tacn:`refine` except it performs typechecking without + resolution of typeclasses. -.. tacv:: simple notypeclasses refine @term + .. tacv:: simple notypeclasses refine @term + :name: simple notypeclasses refine - This tactic behaves like ``simple refine`` except it performs typechecking - without resolution of typeclasses. + This tactic behaves like :tacn:`simple refine` except it performs typechecking + without resolution of typeclasses. -.. tacv:: apply @term +.. tacn:: apply @term :name: apply -This tactic applies to any goal. The argument term is a term well-formed in the -local context. The tactic apply tries to match the current goal against the -conclusion of the type of term. If it succeeds, then the tactic returns as many -subgoals as the number of non-dependent premises of the type of term. If the -conclusion of the type of term does not match the goal *and* the conclusion is -an inductive type isomorphic to a tuple type, then each component of the tuple -is recursively matched to the goal in the left-to-right order. + This tactic applies to any goal. The argument term is a term well-formed in the + local context. The tactic apply tries to match the current goal against the + conclusion of the type of term. If it succeeds, then the tactic returns as many + subgoals as the number of non-dependent premises of the type of term. If the + conclusion of the type of term does not match the goal *and* the conclusion is + an inductive type isomorphic to a tuple type, then each component of the tuple + is recursively matched to the goal in the left-to-right order. -The tactic ``apply`` relies on first-order unification with dependent types -unless the conclusion of the type of ``term`` is of the form :g:`P (t`:sub:`1` -:g:`...` :g:`t`:sub:`n` :g:`)` with `P` to be instantiated. In the latter case, the behavior -depends on the form of the goal. If the goal is of the form -:g:`(fun x => Q) u`:sub:`1` :g:`...` :g:`u`:sub:`n` and the :g:`t`:sub:`i` and -:g:`u`:sub:`i` unifies, then :g:`P` is taken to be :g:`(fun x => Q)`. Otherwise, -``apply`` tries to define :g:`P` by abstracting over :g:`t`:sub:`1` :g:`...` -:g:`t`:sub:`n` in the goal. See :tacn:`pattern` to transform the goal so that it -gets the form :g:`(fun x => Q) u`:sub:`1` :g:`...` :g:`u`:sub:`n`. + The tactic :tacn:`apply` relies on first-order unification with dependent types + unless the conclusion of the type of :token:`term` is of the form :g:`P (t`:sub:`1` + :g:`...` :g:`t`:sub:`n` :g:`)` with `P` to be instantiated. In the latter case, the behavior + depends on the form of the goal. If the goal is of the form + :g:`(fun x => Q) u`:sub:`1` :g:`...` :g:`u`:sub:`n` and the :g:`t`:sub:`i` and + :g:`u`:sub:`i` unifies, then :g:`P` is taken to be :g:`(fun x => Q)`. Otherwise, + :tacn:`apply` tries to define :g:`P` by abstracting over :g:`t`:sub:`1` :g:`...` + :g:`t`:sub:`n` in the goal. See :tacn:`pattern` to transform the goal so that it + gets the form :g:`(fun x => Q) u`:sub:`1` :g:`...` :g:`u`:sub:`n`. -.. exn:: Unable to unify ... with ... . + .. exn:: Unable to unify ... with ... . -The apply tactic failed to match the conclusion of term and the current goal. -You can help the apply tactic by transforming your goal with the -:ref:`change <change_term>` or :tacn:`pattern` tactics. + The apply tactic failed to match the conclusion of :token:`term` and the + current goal. You can help the apply tactic by transforming your goal with + the :tacn:`change` or :tacn:`pattern` tactics. -.. exn:: Unable to find an instance for the variables {+ @ident}. + .. exn:: Unable to find an instance for the variables {+ @ident}. -This occurs when some instantiations of the premises of term are not deducible -from the unification. This is the case, for instance, when you want to apply a -transitivity property. In this case, you have to use one of the variants below: + This occurs when some instantiations of the premises of :token:`term` are not deducible + from the unification. This is the case, for instance, when you want to apply a + transitivity property. In this case, you have to use one of the variants below: -.. cmd:: apply @term with {+ @term} + .. tacv:: apply @term with {+ @term} -Provides apply with explicit instantiations for all dependent premises of the -type of term that do not occur in the conclusion and consequently cannot be -found by unification. Notice that the collection :n:`{+ @term}` must be given -according to the order of these dependent premises of the type of term. + Provides apply with explicit instantiations for all dependent premises of the + type of term that do not occur in the conclusion and consequently cannot be + found by unification. Notice that the collection :n:`{+ @term}` must be given + according to the order of these dependent premises of the type of term. -.. exn:: Not the right number of missing arguments. + .. exn:: Not the right number of missing arguments. -.. tacv:: apply @term with @bindings_list + .. tacv:: apply @term with @bindings_list -This also provides apply with values for instantiating premises. Here, variables -are referred by names and non-dependent products by increasing numbers (see -:ref:`bindings list <bindingslist>`). + This also provides apply with values for instantiating premises. Here, variables + are referred by names and non-dependent products by increasing numbers (see + :ref:`bindings list <bindingslist>`). -.. tacv:: apply {+, @term} + .. tacv:: apply {+, @term} -This is a shortcut for ``apply term``:sub:`1` -``; [.. | ... ; [ .. | apply`` ``term``:sub:`n` ``] ... ]``, -i.e. for the successive applications of ``term``:sub:`i+1` on the last subgoal -generated by ``apply term``:sub:`i` , starting from the application of -``term``:sub:`1`. + This is a shortcut for :n:`apply @term`:sub:`1` + :n:`; [.. | ... ; [ .. | apply @term`:sub:`n` :n:`] ... ]`, + i.e. for the successive applications of :token:`term`:sub:`i+1` on the last subgoal + generated by :n:`apply @term`:sub:`i` , starting from the application of + :token:`term`:sub:`1`. -.. tacv:: eapply @term - :name: eapply + .. tacv:: eapply @term + :name: eapply -The tactic ``eapply`` behaves like ``apply`` but it does not fail when no -instantiations are deducible for some variables in the premises. Rather, it -turns these variables into existential variables which are variables still to -instantiate (see :ref:`TODO-2.11-ExistentialVariables`). The instantiation is -intended to be found later in the proof. + The tactic :tacn:`eapply` behaves like :tacn:`apply` but it does not fail when no + instantiations are deducible for some variables in the premises. Rather, it + turns these variables into existential variables which are variables still to + instantiate (see :ref:`Existential-Variables`). The instantiation is + intended to be found later in the proof. -.. tacv:: simple apply @term. + .. tacv:: simple apply @term. + :name: simple apply -This behaves like ``apply`` but it reasons modulo conversion only on subterms -that contain no variables to instantiate. For instance, the following example -does not succeed because it would require the conversion of ``id ?foo`` and -``O``. + This behaves like :tacn:`apply` but it reasons modulo conversion only on subterms + that contain no variables to instantiate. For instance, the following example + does not succeed because it would require the conversion of ``id ?foo`` and + :g:`O`. -.. example:: + .. example:: - .. coqtop:: all + .. coqtop:: all - Definition id (x : nat) := x. - Hypothesis H : forall y, id y = y. - Goal O = O. - Fail simple apply H. + Definition id (x : nat) := x. + Parameter H : forall y, id y = y. + Goal O = O. + Fail simple apply H. -Because it reasons modulo a limited amount of conversion, ``simple apply`` fails -quicker than ``apply`` and it is then well-suited for uses in user-defined -tactics that backtrack often. Moreover, it does not traverse tuples as ``apply`` -does. + Because it reasons modulo a limited amount of conversion, :tacn:`simple apply` fails + quicker than :tacn:`apply` and it is then well-suited for uses in user-defined + tactics that backtrack often. Moreover, it does not traverse tuples as :tacn:`apply` + does. -.. tacv:: {? simple} apply {+, @term {? with @bindings_list}} -.. tacv:: {? simple} eapply {+, @term {? with @bindings_list}} + .. tacv:: {? simple} apply {+, @term {? with @bindings_list}} + .. tacv:: {? simple} eapply {+, @term {? with @bindings_list}} + :name: simple eapply -This summarizes the different syntaxes for ``apply`` and ``eapply``. + This summarizes the different syntaxes for :tacn:`apply` and :tacn:`eapply`. -.. tacv:: lapply @term - :name: `lapply + .. tacv:: lapply @term + :name: lapply -This tactic applies to any goal, say :g:`G`. The argument term has to be -well-formed in the current context, its type being reducible to a non-dependent -product :g:`A -> B` with :g:`B` possibly containing products. Then it generates -two subgoals :g:`B->G` and :g:`A`. Applying ``lapply H`` (where :g:`H` has type -:g:`A->B` and :g:`B` does not start with a product) does the same as giving the -sequence ``cut B. 2:apply H.`` where ``cut`` is described below. + This tactic applies to any goal, say :g:`G`. The argument term has to be + well-formed in the current context, its type being reducible to a non-dependent + product :g:`A -> B` with :g:`B` possibly containing products. Then it generates + two subgoals :g:`B->G` and :g:`A`. Applying ``lapply H`` (where :g:`H` has type + :g:`A->B` and :g:`B` does not start with a product) does the same as giving the + sequence ``cut B. 2:apply H.`` where ``cut`` is described below. -.. warn:: When @term contains more than one non dependent product the tactic lapply only takes into account the first product. + .. warn:: When @term contains more than one non dependent product the tactic lapply only takes into account the first product. .. example:: Assume we have a transitive relation ``R`` on ``nat``: @@ -435,7 +445,7 @@ sequence ``cut B. 2:apply H.`` where ``cut`` is described below. ``forall A, ... -> A``. Excluding this kind of lemma can be avoided by setting the following option: -.. opt:: Set Universal Lemma Under Conjunction. +.. opt:: Universal Lemma Under Conjunction This option, which preserves compatibility with versions of Coq prior to 8.4 is also available for :n:`apply @term in @ident` (see :tacn:`apply ... in`). @@ -493,7 +503,7 @@ sequence ``cut B. 2:apply H.`` where ``cut`` is described below. .. tacv:: eapply {+, @term with @bindings_list} in @ident as @intro_pattern. - This works as :tacn:`apply ... in as` but using ``eapply``. + This works as :tacn:`apply ... in ... as` but using ``eapply``. .. tacv:: simple apply @term in @ident @@ -501,15 +511,15 @@ sequence ``cut B. 2:apply H.`` where ``cut`` is described below. on subterms that contain no variables to instantiate. For instance, if :g:`id := fun x:nat => x` and :g:`H: forall y, id y = y -> True` and :g:`H0 : O = O` then ``simple apply H in H0`` does not succeed because it - would require the conversion of :g:`id ?1234` and :g:`O` where :g:`?1234` is - a variable to instantiate. Tactic :n:`simple apply @term in @ident` does not + would require the conversion of :g:`id ?x` and :g:`O` where :g:`?x` is + an existential variable to instantiate. Tactic :n:`simple apply @term in @ident` does not either traverse tuples as :n:`apply @term in @ident` does. .. tacv:: {? simple} apply {+, @term {? with @bindings_list}} in @ident {? as @intro_pattern} .. tacv:: {? simple} eapply {+, @term {? with @bindings_list}} in @ident {? as @intro_pattern} - This summarizes the different syntactic variants of :n:`apply @term in - @ident` and :n:`eapply @term in @ident`. + This summarizes the different syntactic variants of :n:`apply @term in @ident` + and :n:`eapply @term in @ident`. .. tacn:: constructor @num :name: constructor @@ -539,14 +549,16 @@ sequence ``cut B. 2:apply H.`` where ``cut`` is described below. The terms in the @bindings_list are checked in the context where constructor is executed and not in the context where @apply is executed (the introductions are not taken into account). .. tacv:: split + :name: split This applies only if :g:`I` has a single constructor. It is then equivalent to :n:`constructor 1.`. It is typically used in the case of a conjunction :g:`A` :math:`\wedge` :g:`B`. -.. exn:: Not an inductive goal with 1 constructor. +.. exn:: Not an inductive goal with 1 constructor .. tacv:: exists @val + :name: exists This applies only if :g:`I` has a single constructor. It is then equivalent to :n:`intros; constructor 1 with @bindings_list.` It is typically used in @@ -559,7 +571,10 @@ sequence ``cut B. 2:apply H.`` where ``cut`` is described below. This iteratively applies :n:`exists @bindings_list`. .. tacv:: left + :name: left + .. tacv:: right + :name: right These tactics apply only if :g:`I` has two constructors, for instance in the case of a disjunction :g:`A` :math:`\vee` :g:`B`. @@ -577,15 +592,25 @@ sequence ``cut B. 2:apply H.`` where ``cut`` is described below. for the appropriate ``i``. .. tacv:: econstructor + :name: econstructor + .. tacv:: eexists + :name: eexists + .. tacv:: esplit + :name: esplit + .. tacv:: eleft + :name: eleft + .. tacv:: eright + :name: eright - These tactics and their variants behave like ``constructor``, ``exists``, - ``split``, ``left``, ``right`` and their variants but they introduce - existential variables instead of failing when the instantiation of a - variable cannot be found (cf. :tacn:`eapply` and :tacn:`apply`). + These tactics and their variants behave like :tacn:`constructor`, + :tacn:`exists`, :tacn:`split`, :tacn:`left`, :tacn:`right` and their variants + but they introduce existential variables instead of failing when the + instantiation of a variable cannot be found (cf. :tacn:`eapply` and + :tacn:`apply`). .. _managingthelocalcontext: @@ -598,48 +623,53 @@ Managing the local context This tactic applies to a goal that is either a product or starts with a let binder. If the goal is a product, the tactic implements the "Lam" rule given in -:ref:`TODO-4.2-Typing-rules` [1]_. If the goal starts with a let binder, then the +:ref:`Typing-rules` [1]_. If the goal starts with a let binder, then the tactic implements a mix of the "Let" and "Conv". -If the current goal is a dependent product :math:`\forall` :g:`x:T, U` (resp +If the current goal is a dependent product :g:`forall x:T, U` (resp :g:`let x:=t in U`) then ``intro`` puts :g:`x:T` (resp :g:`x:=t`) in the local context. The new subgoal is :g:`U`. If the goal is a non-dependent product :g:`T`:math:`\rightarrow`:g:`U`, then it puts in the local context either :g:`Hn:T` (if :g:`T` is of type :g:`Set` or -:g:`Prop`) or Xn:T (if the type of :g:`T` is :g:`Type`). The optional index +:g:`Prop`) or :g:`Xn:T` (if the type of :g:`T` is :g:`Type`). The optional index ``n`` is such that ``Hn`` or ``Xn`` is a fresh identifier. In both cases, the new subgoal is :g:`U`. -If the goal is neither a product nor starting with a let definition, +If the goal is an existential variable, ``intro`` forces the resolution of the +existential variable into a dependent product :math:`forall`:g:`x:?X, ?Y`, puts +:g:`x:?X` in the local context and leaves :g:`?Y` as a new subgoal allowed to +depend on :g:`x`. + the tactic ``intro`` applies the tactic ``hnf`` until the tactic ``intro`` can be applied or the goal is not head-reducible. .. exn:: No product even after head-reduction. -.. exn:: ident is already used. +.. exn:: @ident is already used. .. tacv:: intros + :name: intros This repeats ``intro`` until it meets the head-constant. It never reduces head-constants and it never fails. -.. tac:: intro @ident +.. tacn:: intro @ident This applies ``intro`` but forces :n:`@ident` to be the name of the introduced hypothesis. -.. exn:: name @ident is already used +.. exn:: Name @ident is already used. .. note:: If a name used by intro hides the base name of a global constant then the latter can still be referred to by a qualified name - (see :ref:`TODO-2.6.2-Qualified-names`). + (see :ref:`Qualified-names`). .. tacv:: intros {+ @ident}. This is equivalent to the composed tactic :n:`intro @ident; ... ; intro @ident`. More generally, the ``intros`` tactic takes a pattern as argument in order to introduce names for components of an inductive definition or to clear introduced hypotheses. This is - explained in :ref:`TODO-8.3.2`. + explained in :ref:`Managingthelocalcontext`. .. tacv:: intros until @ident @@ -647,7 +677,7 @@ be applied or the goal is not head-reducible. `(@ident:term)` and discharges the variable named `ident` of the current goal. -.. exn:: No such hypothesis in current goal +.. exn:: No such hypothesis in current goal. .. tacv:: intros until @num @@ -676,7 +706,7 @@ be applied or the goal is not head-reducible. too so as to respect the order of dependencies between hypotheses. Note that :n:`intro at bottom` is a synonym for :n:`intro` with no argument. -.. exn:: No such hypothesis : @ident. +.. exn:: No such hypothesis: @ident. .. tacv:: intro @ident after @ident .. tacv:: intro @ident before @ident @@ -685,7 +715,7 @@ be applied or the goal is not head-reducible. These tactics behave as previously but naming the introduced hypothesis :n:`@ident`. It is equivalent to :n:`intro @ident` followed by the - appropriate call to move (see :tacn:`move ... after`). + appropriate call to ``move`` (see :tacn:`move ... after ...`). .. tacn:: intros @intro_pattern_list :name: intros ... @@ -730,7 +760,7 @@ be applied or the goal is not head-reducible. Assuming a goal of type :g:`Q → P` (non-dependent product), or of type - :math:`\forall`:g:`x:T, P` (dependent product), the behavior of + :g:`forall x:T, P` (dependent product), the behavior of :n:`intros p` is defined inductively over the structure of the introduction pattern :n:`p`: @@ -827,15 +857,10 @@ quantification or an implication. so that all the arguments of the i-th constructors of the corresponding inductive type are introduced can be controlled with the following option: - .. cmd:: Set Bracketing Last Introduction Pattern. - - Force completion, if needed, when the last introduction pattern is a - disjunctive or conjunctive pattern (this is the default). + .. opt:: Bracketing Last Introduction Pattern - .. cmd:: Unset Bracketing Last Introduction Pattern. - - Deactivate completion when the last introduction pattern is a disjunctive or - conjunctive pattern. + Force completion, if needed, when the last introduction pattern is a + disjunctive or conjunctive pattern (on by default). .. tacn:: clear @ident :name: clear @@ -854,13 +879,6 @@ quantification or an implication. This is equivalent to :n:`clear @ident. ... clear @ident.` -.. tacv:: clearbody @ident - - This tactic expects :n:`@ident` to be a local definition then clears its - body. Otherwise said, this tactic turns a definition into an assumption. - -.. exn:: @ident is not a local definition - .. tacv:: clear - {+ @ident} This tactic clears all the hypotheses except the ones depending in the @@ -875,24 +893,33 @@ quantification or an implication. This clears the hypothesis :n:`@ident` and all the hypotheses that depend on it. +.. tacv:: clearbody {+ @ident} + :name: clearbody + + This tactic expects :n:`{+ @ident}` to be local definitions and clears their + respective bodies. + In other words, it turns the given definitions into assumptions. + +.. exn:: @ident is not a local definition. + .. tacn:: revert {+ @ident} - :name: revert ... + :name: revert -This applies to any goal with variables :n:`{+ @ident}`. It moves the hypotheses -(possibly defined) to the goal, if this respects dependencies. This tactic is -the inverse of :tacn:`intro`. + This applies to any goal with variables :n:`{+ @ident}`. It moves the hypotheses + (possibly defined) to the goal, if this respects dependencies. This tactic is + the inverse of :tacn:`intro`. .. exn:: No such hypothesis. .. exn:: @ident is used in the hypothesis @ident. -.. tac:: revert dependent @ident +.. tacn:: revert dependent @ident This moves to the goal the hypothesis :n:`@ident` and all the hypotheses that depend on it. .. tacn:: move @ident after @ident - :name: move .. after ... + :name: move ... after ... This moves the hypothesis named :n:`@ident` in the local context after the hypothesis named :n:`@ident`, where “after” is in reference to the @@ -926,9 +953,9 @@ the inverse of :tacn:`intro`. This moves ident at the bottom of the local context (at the end of the context). -.. exn:: No such hypothesis -.. exn:: Cannot move @ident after @ident : it occurs in the type of @ident -.. exn:: Cannot move @ident after @ident : it depends on @ident +.. exn:: No such hypothesis. +.. exn:: Cannot move @ident after @ident : it occurs in the type of @ident. +.. exn:: Cannot move @ident after @ident : it depends on @ident. .. example:: .. coqtop:: all @@ -955,8 +982,8 @@ The name of the hypothesis in the proof-term, however, is left unchanged. particular, the target identifiers may contain identifiers that exist in the source context, as long as the latter are also renamed by the same tactic. -.. exn:: No such hypothesis -.. exn:: @ident is already used +.. exn:: No such hypothesis. +.. exn:: @ident is already used. .. tacn:: set (@ident := @term) :name: set @@ -968,7 +995,7 @@ The name of the hypothesis in the proof-term, however, is left unchanged. first checks that all subterms matching the pattern are compatible before doing the replacement using the leftmost subterm matching the pattern. -.. exn:: The variable @ident is already defined +.. exn:: The variable @ident is already defined. .. tacv:: set (@ident := @term ) in @goal_occurrences @@ -992,6 +1019,7 @@ The name of the hypothesis in the proof-term, however, is left unchanged. .. tacv:: eset (@ident {+ @binder} := @term ) in @goal_occurrences .. tacv:: eset @term in @goal_occurrences + :name: eset While the different variants of :tacn:`set` expect that no existential variables are generated by the tactic, :n:`eset` removes this constraint. In @@ -999,6 +1027,7 @@ The name of the hypothesis in the proof-term, however, is left unchanged. :tacn:`epose`, i.e. when the :`@term` does not occur in the goal. .. tacv:: remember @term as @ident + :name: remember This behaves as :n:`set (@ident:= @term ) in *` and using a logical (Leibniz’s) equality instead of a local definition. @@ -1016,6 +1045,8 @@ The name of the hypothesis in the proof-term, however, is left unchanged. .. tacv:: eremember @term as @ident .. tacv:: eremember @term as @ident in @goal_occurrences .. tacv:: eremember @term as @ident eqn:@ident + :name: eremember + While the different variants of :n:`remember` expect that no existential variables are generated by the tactic, :n:`eremember` removes this constraint. @@ -1067,7 +1098,7 @@ The name of the hypothesis in the proof-term, however, is left unchanged. This decomposes record types (inductive types with one constructor, like "and" and "exists" and those defined with the Record macro, see - :ref:`TODO-2.1`). + :ref:`record-types`). .. _controllingtheproofflow: @@ -1082,24 +1113,25 @@ Controlling the proof flow :g:`U` [2]_. The subgoal :g:`U` comes first in the list of subgoals remaining to prove. -.. exn:: Not a proposition or a type +.. exn:: Not a proposition or a type. Arises when the argument form is neither of type :g:`Prop`, :g:`Set` nor :g:`Type`. .. tacv:: assert form - This behaves as :n:`assert (@ident : form ) but :n:`@ident` is generated by + This behaves as :n:`assert (@ident : form)` but :n:`@ident` is generated by Coq. -.. tacv:: assert form by tactic +.. tacv:: assert @form by @tactic This tactic behaves like :n:`assert` but applies tactic to solve the subgoals generated by assert. - .. exn:: Proof is not complete + .. exn:: Proof is not complete. + :name: Proof is not complete. (assert) -.. tacv:: assert form as intro_pattern +.. tacv:: assert @form as @intro_pattern If :n:`intro_pattern` is a naming introduction pattern (see :tacn:`intro`), the hypothesis is named after this introduction pattern (in particular, if @@ -1108,7 +1140,7 @@ Controlling the proof flow introduction pattern, the tactic behaves like :n:`assert form` followed by the action done by this introduction pattern. -.. tacv:: assert form as intro_pattern by tactic +.. tacv:: assert @form as @intro_pattern by @tactic This combines the two previous variants of :n:`assert`. @@ -1118,9 +1150,10 @@ Controlling the proof flow the type of :g:`term`. This is deprecated in favor of :n:`pose proof`. If the head of term is :n:`@ident`, the tactic behaves as :n:`specialize @term`. - .. exn:: Variable @ident is already declared + .. exn:: Variable @ident is already declared. .. tacv:: eassert form as intro_pattern by tactic + :name: eassert .. tacv:: assert (@ident := @term) @@ -1130,6 +1163,7 @@ Controlling the proof flow to prove it. .. tacv:: pose proof @term {? as intro_pattern} + :name: pose proof This tactic behaves like :n:`assert T {? as intro_pattern} by exact @term` where :g:`T` is the type of :g:`term`. In particular, @@ -1143,6 +1177,7 @@ Controlling the proof flow the tactic, :n:`epose proof` removes this constraint. .. tacv:: enough (@ident : form) + :name: enough This adds a new hypothesis of name :n:`@ident` asserting :n:`form` to the goal the tactic :n:`enough` is applied to. A new subgoal stating :n:`form` is @@ -1158,9 +1193,9 @@ Controlling the proof flow This behaves like :n:`enough form` using :n:`intro_pattern` to name or destruct the new hypothesis. -.. tacv:: enough (@ident : form) by tactic -.. tacv:: enough form by tactic -.. tacv:: enough form as intro_pattern by tactic +.. tacv:: enough (@ident : @form) by @tactic +.. tacv:: enough @form by @tactic +.. tacv:: enough @form as @intro_pattern by @tactic This behaves as above but with :n:`tactic` expected to solve the initial goal after the extra assumption :n:`form` is added and possibly destructed. If the @@ -1168,22 +1203,27 @@ Controlling the proof flow applied to all of them. .. tacv:: eenough (@ident : form) by tactic + :name: eenough + .. tacv:: eenough form by tactic + .. tacv:: eenough form as intro_pattern by tactic While the different variants of :n:`enough` expect that no existential variables are generated by the tactic, :n:`eenough` removes this constraint. -.. tacv:: cut form +.. tacv:: cut @form + :name: cut This tactic applies to any goal. It implements the non-dependent case of - the “App” rule given in :ref:`TODO-4.2`. (This is Modus Ponens inference + the “App” rule given in :ref:`typing-rules`. (This is Modus Ponens inference rule.) :n:`cut U` transforms the current goal :g:`T` into the two following subgoals: :g:`U -> T` and :g:`U`. The subgoal :g:`U -> T` comes first in the list of remaining subgoal to prove. .. tacv:: specialize (ident {* @term}) {? as intro_pattern} .. tacv:: specialize ident with @bindings_list {? as intro_pattern} + :name: specialize The tactic :n:`specialize` works on local hypothesis :n:`@ident`. The premises of this hypothesis (either universal quantifications or @@ -1202,8 +1242,8 @@ Controlling the proof flow the goal. The :n:`as` clause is especially useful in this case to immediately introduce the instantiated statement as a local hypothesis. - .. exn:: @ident is used in hypothesis @ident - .. exn:: @ident is used in conclusion + .. exn:: @ident is used in hypothesis @ident. + .. exn:: @ident is used in conclusion. .. tacn:: generalize @term :name: generalize @@ -1236,7 +1276,7 @@ name of the variable (here :g:`n`) is chosen based on :g:`T`. This is equivalent to :n:`generalize @term` but it generalizes only over the specified occurrences of :n:`@term` (counting from left to right on the - expression printed using option :g:`Set Printing All`). + expression printed using option :opt:`Printing All`). .. tacv:: generalize @term as @ident @@ -1268,7 +1308,7 @@ name of the variable (here :g:`n`) is chosen based on :g:`T`. :n:`refine @term` (preferred alternative). .. note:: To be able to refer to an existential variable by name, the user - must have given the name explicitly (see :ref:`TODO-2.11`). + must have given the name explicitly (see :ref:`Existential-Variables`). .. note:: When you are referring to hypotheses which you did not name explicitly, be aware that Coq may make a different decision on how to @@ -1327,7 +1367,7 @@ goals cannot be closed with :g:`Qed` but only with :g:`Admitted`. a singleton inductive type (e.g. :g:`True` or :g:`x=x`), or two contradictory hypotheses. -.. exn:: No such assumption +.. exn:: No such assumption. .. tacv:: contradiction @ident @@ -1353,11 +1393,13 @@ goals cannot be closed with :g:`Qed` but only with :g:`Admitted`. then required to prove that False is indeed provable in the current context. This tactic is a macro for :n:`elimtype False`. +.. _CaseAnalysisAndInduction: + Case analysis and induction ------------------------------- The tactics presented in this section implement induction or case -analysis on inductive or co-inductive objects (see :ref:`TODO-4.5`). +analysis on inductive or co-inductive objects (see :ref:`inductive-definitions`). .. tacn:: destruct @term :name: destruct @@ -1423,6 +1465,7 @@ analysis on inductive or co-inductive objects (see :ref:`TODO-4.5`). dependent premises of the type of :n:`@term` (see :ref:`syntax of bindings <bindingslist>`). .. tacv:: edestruct @term + :name: edestruct This tactic behaves like :n:`destruct @term` except that it does not fail if the instance of a dependent premises of the type of :n:`@term` is not @@ -1449,6 +1492,7 @@ analysis on inductive or co-inductive objects (see :ref:`TODO-4.5`). the effects of the `with`, `as`, `eqn:`, `using`, and `in` clauses. .. tacv:: case term + :name: case The tactic :n:`case` is a more basic tactic to perform case analysis without recursion. It behaves as :n:`elim @term` but using a case-analysis @@ -1458,14 +1502,15 @@ analysis on inductive or co-inductive objects (see :ref:`TODO-4.5`). Analogous to :n:`elim @term with @bindings_list` above. -.. tacv:: ecase @term -.. tacv:: ecase @term with @bindings_list +.. tacv:: ecase @term {? with @bindings_list } + :name: ecase In case the type of :n:`@term` has dependent premises, or dependent premises whose values are not inferable from the :n:`with @bindings_list` clause, :n:`ecase` turns them into existential variables to be resolved later on. .. tacv:: simple destruct @ident + :name: simple destruct This tactic behaves as :n:`intros until @ident; case @ident` when :n:`@ident` is a quantified variable of the goal. @@ -1528,9 +1573,9 @@ analysis on inductive or co-inductive objects (see :ref:`TODO-4.5`). intros n H. induction n. -.. exn:: Not an inductive product +.. exn:: Not an inductive product. -.. exn:: Unable to find an instance for the variables @ident ... @ident +.. exn:: Unable to find an instance for the variables @ident ... @ident. Use in this case the variant :tacn:`elim ... with` below. @@ -1556,6 +1601,7 @@ analysis on inductive or co-inductive objects (see :ref:`TODO-4.5`). premises of the type of :n:`term` (see :ref:`bindings list <bindingslist>`). .. tacv:: einduction @term + :name: einduction This tactic behaves like :tacn:`induction` except that it does not fail if some dependent premise of the type of :n:`@term` is not inferable. Instead, @@ -1628,6 +1674,7 @@ analysis on inductive or co-inductive objects (see :ref:`TODO-4.5`). (see :ref:`bindings list <bindingslist>`). .. tacv:: eelim @term + :name: eelim In case the type of :n:`@term` has dependent premises, this turns them into existential variables to be resolved later on. @@ -1646,7 +1693,8 @@ analysis on inductive or co-inductive objects (see :ref:`TODO-4.5`). These are the most general forms of ``elim`` and ``eelim``. It combines the effects of the ``using`` clause and of the two uses of the ``with`` clause. -.. tacv:: elimtype form +.. tacv:: elimtype @form + :name: elimtype The argument :n:`form` must be inductively defined. :n:`elimtype I` is equivalent to :n:`cut I. intro Hn; elim Hn; clear Hn.` Therefore the @@ -1656,6 +1704,7 @@ analysis on inductive or co-inductive objects (see :ref:`TODO-4.5`). :n:`elimtype I; 2:exact t.` .. tacv:: simple induction @ident + :name: simple induction This tactic behaves as :n:`intros until @ident; elim @ident` when :n:`@ident` is a quantified variable of the goal. @@ -1740,13 +1789,14 @@ analysis on inductive or co-inductive objects (see :ref:`TODO-4.5`). other ones need not be further generalized. .. tacv:: dependent destruction @ident + :name: dependent destruction This performs the generalization of the instance :n:`@ident` but uses ``destruct`` instead of induction on the generalized hypothesis. This gives results equivalent to ``inversion`` or ``dependent inversion`` if the hypothesis is dependent. -See also :ref:`TODO-10.1-dependentinduction` for a larger example of ``dependent induction`` +See also the larger example of :tacn:`dependent induction` and an explanation of the underlying technique. .. tacn:: function induction (@qualid {+ @term}) @@ -1754,8 +1804,8 @@ and an explanation of the underlying technique. The tactic functional induction performs case analysis and induction following the definition of a function. It makes use of a principle - generated by ``Function`` (see :ref:`TODO-2.3-Advancedrecursivefunctions`) or - ``Functional Scheme`` (see :ref:`TODO-13.2-Generationofinductionschemeswithfunctionalscheme`). + generated by ``Function`` (see :ref:`advanced-recursive-functions`) or + ``Functional Scheme`` (see :ref:`functional-scheme`). Note that this tactic is only available after a .. example:: @@ -1781,26 +1831,26 @@ and an explanation of the underlying technique. :n:`functional induction (f x1 x2 x3)` is actually a wrapper for :n:`induction x1, x2, x3, (f x1 x2 x3) using @qualid` followed by a cleaning phase, where :n:`@qualid` is the induction principle registered for :g:`f` - (by the ``Function`` (see :ref:`TODO-2.3-Advancedrecursivefunctions`) or - ``Functional Scheme`` (see :ref:`TODO-13.2-Generationofinductionschemeswithfunctionalscheme`) + (by the ``Function`` (see :ref:`advanced-recursive-functions`) or + ``Functional Scheme`` (see :ref:`functional-scheme`) command) corresponding to the sort of the goal. Therefore ``functional induction`` may fail if the induction scheme :n:`@qualid` is not - defined. See also :ref:`TODO-2.3-Advancedrecursivefunctions` for the function + defined. See also :ref:`advanced-recursive-functions` for the function terms accepted by ``Function``. .. note:: There is a difference between obtaining an induction scheme - for a function by using :g:`Function` (see :ref:`TODO-2.3-Advancedrecursivefunctions`) + for a function by using :g:`Function` (see :ref:`advanced-recursive-functions`) and by using :g:`Functional Scheme` after a normal definition using - :g:`Fixpoint` or :g:`Definition`. See :ref:`TODO-2.3-Advancedrecursivefunctions` + :g:`Fixpoint` or :g:`Definition`. See :ref:`advanced-recursive-functions` for details. -See also: :ref:`TODO-2.3-Advancedrecursivefunctions` - :ref:`TODO-13.2-Generationofinductionschemeswithfunctionalscheme` +See also: :ref:`advanced-recursive-functions` + :ref:`functional-scheme` :tacn:`inversion` -.. exn:: Cannot find induction information on @qualid -.. exn:: Not the right number of induction arguments +.. exn:: Cannot find induction information on @qualid. +.. exn:: Not the right number of induction arguments. .. tacv:: functional induction (@qualid {+ @term}) as @disj_conj_intro_pattern using @term with @bindings_list @@ -1833,8 +1883,8 @@ See also: :ref:`TODO-2.3-Advancedrecursivefunctions` :n:`@ident` is first introduced in the local context using :n:`intros until @ident`. -.. exn:: No primitive equality found -.. exn:: Not a discriminable equality +.. exn:: No primitive equality found. +.. exn:: Not a discriminable equality. .. tacv:: discriminate @num @@ -1849,6 +1899,7 @@ See also: :ref:`TODO-2.3-Advancedrecursivefunctions` .. tacv:: ediscriminate @num .. tacv:: ediscriminate @term {? with @bindings_list} + :name: ediscriminate This works the same as ``discriminate`` but if the type of :n:`@term`, or the type of the hypothesis referred to by :n:`@num`, has uninstantiated @@ -1861,7 +1912,7 @@ See also: :ref:`TODO-2.3-Advancedrecursivefunctions` the form :n:`@term <> @term`, this behaves as :n:`intro @ident; discriminate @ident`. - .. exn:: No discriminable equalities + .. exn:: No discriminable equalities. .. tacn:: injection @term :name: injection @@ -1872,7 +1923,7 @@ See also: :ref:`TODO-2.3-Advancedrecursivefunctions` :g:`t`:sub:`1` and :g:`t`:sub:`2` are equal too. If :n:`@term` is a proof of a statement of conclusion :n:`@term = @term`, - then ``injection`` applies the injectivity of constructors as deep as + then :tacn:`injection` applies the injectivity of constructors as deep as possible to derive the equality of all the subterms of :n:`@term` and :n:`@term` at positions where the terms start to differ. For example, from :g:`(S p, S n) = (q, S (S m))` we may derive :g:`S p = q` and @@ -1882,90 +1933,96 @@ See also: :ref:`TODO-2.3-Advancedrecursivefunctions` equality of all the subterms at positions where they differ and adds them as antecedents to the conclusion of the current goal. -.. example:: + .. example:: - Consider the following goal: + Consider the following goal: - .. coqtop:: reset all + .. coqtop:: in - Inductive list : Set := - | nil : list - | cons : nat -> list -> list. - Variable P : list -> Prop. - Goal forall l n, P nil -> cons n l = cons 0 nil -> P l. - intros. - injection H0. + Inductive list : Set := + | nil : list + | cons : nat -> list -> list. + Parameter P : list -> Prop. + Goal forall l n, P nil -> cons n l = cons 0 nil -> P l. + .. coqtop:: all -Beware that injection yields an equality in a sigma type whenever the -injected object has a dependent type :g:`P` with its two instances in -different types :g:`(P t`:sub:`1` :g:`... t`:sub:`n` :g:`)` and -:g:`(P u`:sub:`1` :g:`... u`:sub:`n` :sub:`)`. If :g:`t`:sub:`1` and -:g:`u`:sub:`1` are the same and have for type an inductive type for which a decidable -equality has been declared using the command ``Scheme Equality`` (see :ref:`TODO-13.1-GenerationofinductionprincipleswithScheme`), -the use of a sigma type is avoided. + intros. + injection H0. -.. note:: - If some quantified hypothesis of the goal is named :n:`@ident`, - then :n:`injection @ident` first introduces the hypothesis in the local - context using :n:`intros until @ident`. + Beware that injection yields an equality in a sigma type whenever the + injected object has a dependent type :g:`P` with its two instances in + different types :g:`(P t`:sub:`1` :g:`... t`:sub:`n` :g:`)` and + :g:`(P u`:sub:`1` :g:`... u`:sub:`n` :sub:`)`. If :g:`t`:sub:`1` and + :g:`u`:sub:`1` are the same and have for type an inductive type for which a decidable + equality has been declared using the command :cmd:`Scheme Equality` + (see :ref:`proofschemes-induction-principles`), + the use of a sigma type is avoided. -.. exn:: Not a projectable equality but a discriminable one -.. exn:: Nothing to do, it is an equality between convertible @terms -.. exn:: Not a primitive equality -.. exn:: Nothing to inject + .. note:: + If some quantified hypothesis of the goal is named :n:`@ident`, + then :n:`injection @ident` first introduces the hypothesis in the local + context using :n:`intros until @ident`. -.. tacv:: injection @num + .. exn:: Not a projectable equality but a discriminable one. + .. exn:: Nothing to do, it is an equality between convertible @terms. + .. exn:: Not a primitive equality. + .. exn:: Nothing to inject. - This does the same thing as :n:`intros until @num` followed by - :n:`injection @ident` where :n:`@ident` is the identifier for the last - introduced hypothesis. + .. tacv:: injection @num -.. tacv:: injection @term with @bindings_list + This does the same thing as :n:`intros until @num` followed by + :n:`injection @ident` where :n:`@ident` is the identifier for the last + introduced hypothesis. - This does the same as :n:`injection @term` but using the given bindings to - instantiate parameters or hypotheses of :n:`@term`. + .. tacv:: injection @term with @bindings_list -.. tacv:: einjection @num -.. tacv:: einjection @term {? with @bindings_list} + This does the same as :n:`injection @term` but using the given bindings to + instantiate parameters or hypotheses of :n:`@term`. - This works the same as :n:`injection` but if the type of :n:`@term`, or the - type of the hypothesis referred to by :n:`@num`, has uninstantiated - parameters, these parameters are left as existential variables. + .. tacv:: einjection @num + :name: einjection + .. tacv:: einjection @term {? with @bindings_list} + + This works the same as :n:`injection` but if the type of :n:`@term`, or the + type of the hypothesis referred to by :n:`@num`, has uninstantiated + parameters, these parameters are left as existential variables. -.. tacv:: injection + .. tacv:: injection - If the current goal is of the form :n:`@term <> @term` , this behaves as - :n:`intro @ident; injection @ident`. + If the current goal is of the form :n:`@term <> @term` , this behaves as + :n:`intro @ident; injection @ident`. - .. exn:: goal does not satisfy the expected preconditions + .. exn:: goal does not satisfy the expected preconditions. -.. tacv:: injection @term {? with @bindings_list} as {+ @intro_pattern} -.. tacv:: injection @num as {+ intro_pattern} -.. tacv:: injection as {+ intro_pattern} -.. tacv:: einjection @term {? with @bindings_list} as {+ intro_pattern} -.. tacv:: einjection @num as {+ intro_pattern} -.. tacv:: einjection as {+ intro_pattern} + .. tacv:: injection @term {? with @bindings_list} as {+ @intro_pattern} + .. tacv:: injection @num as {+ intro_pattern} + .. tacv:: injection as {+ intro_pattern} + .. tacv:: einjection @term {? with @bindings_list} as {+ intro_pattern} + .. tacv:: einjection @num as {+ intro_pattern} + .. tacv:: einjection as {+ intro_pattern} These variants apply :n:`intros {+ @intro_pattern}` after the call to - ``injection`` or ``einjection`` so that all equalities generated are moved in + :tacn:`injection` or :tacn:`einjection` so that all equalities generated are moved in the context of hypotheses. The number of :n:`@intro_pattern` must not exceed the number of equalities newly generated. If it is smaller, fresh names are automatically generated to adjust the list of :n:`@intro_pattern` to the number of new equalities. The original equality is erased if it corresponds to an hypothesis. -It is possible to ensure that :n:`injection @term` erases the original -hypothesis and leaves the generated equalities in the context rather -than putting them as antecedents of the current goal, as if giving -:n:`injection @term as` (with an empty list of names). To obtain this -behavior, the option ``Set Structural Injection`` must be activated. This -option is off by default. + .. opt:: Structural Injection -By default, ``injection`` only creates new equalities between :n:`@terms` whose -type is in sort :g:`Type` or :g:`Set`, thus implementing a special behavior for -objects that are proofs of a statement in :g:`Prop`. This behavior can be -turned off by setting the option ``Set Keep Proof Equalities``. + This option ensure that :n:`injection @term` erases the original hypothesis + and leaves the generated equalities in the context rather than putting them + as antecedents of the current goal, as if giving :n:`injection @term as` + (with an empty list of names). This option is off by default. + + .. opt:: Keep Proof Equalities + + By default, :tacn:`injection` only creates new equalities between :n:`@terms` + whose type is in sort :g:`Type` or :g:`Set`, thus implementing a special + behavior for objects that are proofs of a statement in :g:`Prop`. This option + controls this behavior. .. tacn:: inversion @ident :name: inversion @@ -1984,15 +2041,15 @@ turned off by setting the option ``Set Keep Proof Equalities``. .. note:: As ``inversion`` proofs may be large in size, we recommend the user to stock the lemmas whenever the same instance needs to be - inverted several times. See :ref:`TODO-13.3-Generationofinversionprincipleswithderiveinversion`. + inverted several times. See :ref:`derive-inversion`. .. note:: Part of the behavior of the ``inversion`` tactic is to generate equalities between expressions that appeared in the hypothesis that is being processed. By default, no equalities are generated if they relate two proofs (i.e. equalities between :n:`@terms` whose type is in sort - :g:`Prop`). This behavior can be turned off by using the option ``Set Keep - Proof Equalities``. + :g:`Prop`). This behavior can be turned off by using the option + :opt`Keep Proof Equalities`. .. tacv:: inversion @num @@ -2093,13 +2150,13 @@ turned off by setting the option ``Set Keep Proof Equalities``. :n:`dependent inversion_clear @ident`. .. tacv:: dependent inversion @ident with @term - :name: dependent inversion ... + :name: dependent inversion ... with ... This variant allows you to specify the generalization of the goal. It is useful when the system fails to generalize the goal automatically. If - :n:`@ident` has type :g:`(I t)` and :g:`I` has type :math:`\forall` - :g:`(x:T), s`, then :n:`@term` must be of type :g:`I:`:math:`\forall` - :g:`(x:T), I x -> s'` where :g:`s'` is the type of the goal. + :n:`@ident` has type :g:`(I t)` and :g:`I` has type :g:`forall (x:T), s`, + then :n:`@term` must be of type :g:`I:forall (x:T), I x -> s'` where + :g:`s'` is the type of the goal. .. tacv:: dependent inversion @ident as @intro_pattern with @term @@ -2108,7 +2165,7 @@ turned off by setting the option ``Set Keep Proof Equalities``. .. tacv:: dependent inversion_clear @ident with @term - Like :tacn:`dependent inversion ...` with but clears :n:`@ident` from the + Like :tacn:`dependent inversion ... with ...` with but clears :n:`@ident` from the local context. .. tacv:: dependent inversion_clear @ident as @intro_pattern with @term @@ -2117,6 +2174,7 @@ turned off by setting the option ``Set Keep Proof Equalities``. :n:`dependent inversion_clear @ident with @term`. .. tacv:: simple inversion @ident + :name: simple inversion It is a very primitive inversion tactic that derives all the necessary equalities but it does not simplify the constraints as ``inversion`` does. @@ -2300,7 +2358,7 @@ turned off by setting the option ``Set Keep Proof Equalities``. arguments are correct is done only at the time of registering the lemma in the environment. To know if the use of induction hypotheses is correct at some time of the interactive development of a proof, use - the command ``Guarded`` (see :ref:`TODO-7.3.2-Guarded`). + the command ``Guarded`` (see Section :ref:`requestinginformation`). .. tacv:: fix @ident @num with {+ (ident {+ @binder} [{struct @ident}] : @type)} @@ -2321,7 +2379,7 @@ turned off by setting the option ``Set Keep Proof Equalities``. done only at the time of registering the lemma in the environment. To know if the use of coinduction hypotheses is correct at some time of the interactive development of a proof, use the command ``Guarded`` - (see :ref:`TODO-7.3.2-Guarded`). + (see Section :ref:`requestinginformation`). .. tacv:: cofix @ident with {+ (@ident {+ @binder} : @type)} @@ -2335,41 +2393,41 @@ Rewriting expressions --------------------- These tactics use the equality :g:`eq:forall A:Type, A->A->Prop` defined in -file ``Logic.v`` (see :ref:`TODO-3.1.2-Logic`). The notation for :g:`eq T t u` is +file ``Logic.v`` (see :ref:`coq-library-logic`). The notation for :g:`eq T t u` is simply :g:`t=u` dropping the implicit type of :g:`t` and :g:`u`. .. tacn:: rewrite @term :name: rewrite -This tactic applies to any goal. The type of :n:`@term` must have the form + This tactic applies to any goal. The type of :token:`term` must have the form -``forall (x``:sub:`1` ``:A``:sub:`1` ``) ... (x``:sub:`n` ``:A``:sub:`n` ``). eq term``:sub:`1` ``term``:sub:`2` ``.`` + ``forall (x``:sub:`1` ``:A``:sub:`1` ``) ... (x``:sub:`n` ``:A``:sub:`n` ``). eq term``:sub:`1` ``term``:sub:`2` ``.`` -where :g:`eq` is the Leibniz equality or a registered setoid equality. + where :g:`eq` is the Leibniz equality or a registered setoid equality. -Then :n:`rewrite @term` finds the first subterm matching `term`\ :sub:`1` in the goal, -resulting in instances `term`:sub:`1`' and `term`:sub:`2`' and then -replaces every occurrence of `term`:subscript:`1`' by `term`:subscript:`2`'. -Hence, some of the variables :g:`x`\ :sub:`i` are solved by unification, -and some of the types :g:`A`\ :sub:`1`:g:`, ..., A`\ :sub:`n` become new -subgoals. + Then :n:`rewrite @term` finds the first subterm matching `term`\ :sub:`1` in the goal, + resulting in instances `term`:sub:`1`' and `term`:sub:`2`' and then + replaces every occurrence of `term`:subscript:`1`' by `term`:subscript:`2`'. + Hence, some of the variables :g:`x`\ :sub:`i` are solved by unification, + and some of the types :g:`A`\ :sub:`1`:g:`, ..., A`\ :sub:`n` become new + subgoals. -.. exn:: The @term provided does not end with an equation + .. exn:: The @term provided does not end with an equation. -.. exn:: Tactic generated a subgoal identical to the original goal. This happens if @term does not occur in the goal. + .. exn:: Tactic generated a subgoal identical to the original goal. This happens if @term does not occur in the goal. -.. tacv:: rewrite -> @term + .. tacv:: rewrite -> @term - Is equivalent to :n:`rewrite @term` + Is equivalent to :n:`rewrite @term` -.. tacv:: rewrite <- @term + .. tacv:: rewrite <- @term - Uses the equality :n:`@term`:sub:`1` :n:`= @term` :sub:`2` from right to left + Uses the equality :n:`@term`:sub:`1` :n:`= @term` :sub:`2` from right to left -.. tacv:: rewrite @term in clause + .. tacv:: rewrite @term in clause - Analogous to :n:`rewrite @term` but rewriting is done following clause - (similarly to :ref:`performing computations <performingcomputations>`). For instance: + Analogous to :n:`rewrite @term` but rewriting is done following clause + (similarly to :ref:`performing computations <performingcomputations>`). For instance: + :n:`rewrite H in H`:sub:`1` will rewrite `H` in the hypothesis `H`:sub:`1` instead of the current goal. @@ -2378,218 +2436,215 @@ subgoals. In particular a failure will happen if any of these three simpler tactics fails. + :n:`rewrite H in * |-` will do :n:`rewrite H in H`:sub:`i` for all hypotheses - :g:`H`:sub:`i` :g:`<> H`. A success will happen as soon as at least one of these - simpler tactics succeeds. + :g:`H`:sub:`i` different from :g:`H`. + A success will happen as soon as at least one of these simpler tactics succeeds. + :n:`rewrite H in *` is a combination of :n:`rewrite H` and :n:`rewrite H in * |-` that succeeds if at least one of these two tactics succeeds. - Orientation :g:`->` or :g:`<-` can be inserted before the :n:`@term` to rewrite. + Orientation :g:`->` or :g:`<-` can be inserted before the :token:`term` to rewrite. -.. tacv:: rewrite @term at occurrences + .. tacv:: rewrite @term at occurrences - Rewrite only the given occurrences of :n:`@term`. Occurrences are - specified from left to right as for pattern (:tacn:`pattern`). The rewrite is - always performed using setoid rewriting, even for Leibniz’s equality, so one - has to ``Import Setoid`` to use this variant. + Rewrite only the given occurrences of :token:`term`. Occurrences are + specified from left to right as for pattern (:tacn:`pattern`). The rewrite is + always performed using setoid rewriting, even for Leibniz’s equality, so one + has to ``Import Setoid`` to use this variant. -.. tacv:: rewrite @term by tactic + .. tacv:: rewrite @term by tactic - Use tactic to completely solve the side-conditions arising from the - :tacn:`rewrite`. + Use tactic to completely solve the side-conditions arising from the + :tacn:`rewrite`. -.. tacv:: rewrite {+ @term} + .. tacv:: rewrite {+, @term} - Is equivalent to the `n` successive tactics :n:`{+ rewrite @term}`, each one - working on the first subgoal generated by the previous one. Orientation - :g:`->` or :g:`<-` can be inserted before each :n:`@term` to rewrite. One - unique clause can be added at the end after the keyword in; it will then - affect all rewrite operations. + Is equivalent to the `n` successive tactics :n:`{+; rewrite @term}`, each one + working on the first subgoal generated by the previous one. Orientation + :g:`->` or :g:`<-` can be inserted before each :token:`term` to rewrite. One + unique clause can be added at the end after the keyword in; it will then + affect all rewrite operations. - In all forms of rewrite described above, a :n:`@term` to rewrite can be - immediately prefixed by one of the following modifiers: + In all forms of rewrite described above, a :token:`term` to rewrite can be + immediately prefixed by one of the following modifiers: - + `?` : the tactic rewrite :n:`?@term` performs the rewrite of :n:`@term` as many - times as possible (perhaps zero time). This form never fails. - + `n?` : works similarly, except that it will do at most `n` rewrites. - + `!` : works as ?, except that at least one rewrite should succeed, otherwise - the tactic fails. - + `n!` (or simply `n`) : precisely `n` rewrites of :n:`@term` will be done, - leading to failure if these n rewrites are not possible. + + `?` : the tactic :n:`rewrite ?@term` performs the rewrite of :token:`term` as many + times as possible (perhaps zero time). This form never fails. + + :n:`@num?` : works similarly, except that it will do at most :token:`num` rewrites. + + `!` : works as `?`, except that at least one rewrite should succeed, otherwise + the tactic fails. + + :n:`@num!` (or simply :n:`@num`) : precisely :token:`num` rewrites of :token:`term` will be done, + leading to failure if these :token:`num` rewrites are not possible. -.. tacv:: erewrite @term + .. tacv:: erewrite @term + :name: erewrite - This tactic works as :n:`rewrite @term` but turning - unresolved bindings into existential variables, if any, instead of - failing. It has the same variants as :tacn:`rewrite` has. + This tactic works as :n:`rewrite @term` but turning + unresolved bindings into existential variables, if any, instead of + failing. It has the same variants as :tacn:`rewrite` has. -.. tacn:: replace @term with @term +.. tacn:: replace @term with @term’ :name: replace This tactic applies to any goal. It replaces all free occurrences of :n:`@term` - in the current goal with :n:`@term` and generates the equality :n:`@term = - @term` as a subgoal. This equality is automatically solved if it occurs among - the assumption, or if its symmetric form occurs. It is equivalent to - :n:`cut @term = @term; [intro H`:sub:`n` :n:`; rewrite <- H`:sub:`n` :n:`; clear H`:sub:`n`:n:`|| assumption || symmetry; try assumption]`. + in the current goal with :n:`@term’` and generates an equality :n:`@term = @term’` + as a subgoal. This equality is automatically solved if it occurs among + the assumptions, or if its symmetric form occurs. It is equivalent to + :n:`cut @term = @term’; [intro H`:sub:`n` :n:`; rewrite <- H`:sub:`n` :n:`; clear H`:sub:`n`:n:`|| assumption || symmetry; try assumption]`. -.. exn:: @terms do not have convertible types + .. exn:: Terms do not have convertible types. -.. tacv:: replace @term with @term by tactic + .. tacv:: replace @term with @term’ by @tactic - This acts as :n:`replace @term` with :n:`@term` but applies tactic to solve the generated - subgoal :n:`@term = @term`. + This acts as :n:`replace @term with @term’` but applies :token:`tactic` to solve the generated + subgoal :n:`@term = @term’`. -.. tacv:: replace @term + .. tacv:: replace @term - Replaces :n:`@term` with :n:`@term’` using the first assumption whose type has - the form :n:`@term = @term’` or :n:`@term’ = @term`. + Replaces :n:`@term` with :n:`@term’` using the first assumption whose type has + the form :n:`@term = @term’` or :n:`@term’ = @term`. -.. tacv:: replace -> @term + .. tacv:: replace -> @term - Replaces :n:`@term` with :n:`@term’` using the first assumption whose type has - the form :n:`@term = @term’` + Replaces :n:`@term` with :n:`@term’` using the first assumption whose type has + the form :n:`@term = @term’` -.. tacv:: replace <- @term + .. tacv:: replace <- @term - Replaces :n:`@term` with :n:`@term’` using the first assumption whose type has - the form :n:`@term’ = @term` + Replaces :n:`@term` with :n:`@term’` using the first assumption whose type has + the form :n:`@term’ = @term` -.. tacv:: replace @term with @term in clause -.. tacv:: replace @term with @term in clause by tactic -.. tacv:: replace @term in clause replace -> @term in clause -.. tacv:: replace <- @term in clause + .. tacv:: replace @term {? with @term} in clause {? by @tactic} + .. tacv:: replace -> @term in clause + .. tacv:: replace <- @term in clause - Acts as before but the replacements take place inclause (see - :ref:`performingcomputations`) and not only in the conclusion of the goal. The - clause argument must not contain any type of nor value of. + Acts as before but the replacements take place in the specified clause (see + :ref:`performingcomputations`) and not only in the conclusion of the goal. The + clause argument must not contain any ``type of`` nor ``value of``. -.. tacv:: cutrewrite <- (@term = @term) + .. tacv:: cutrewrite <- (@term = @term’) + :name: cutrewrite - This tactic is deprecated. It acts like :n:`replace @term with @term`, or, - equivalently as :n:`enough (@term = @term) as <-`. + This tactic is deprecated. It can be replaced by :n:`enough (@term = @term’) as <-`. -.. tacv:: cutrewrite -> (@term = @term) + .. tacv:: cutrewrite -> (@term = @term’) - This tactic is deprecated. It can be replaced by enough :n:`(@term = @term) as ->`. + This tactic is deprecated. It can be replaced by :n:`enough (@term = @term’) as ->`. .. tacn:: subst @ident :name: subst + This tactic applies to a goal that has :n:`@ident` in its context and (at + least) one hypothesis, say :g:`H`, of type :n:`@ident = t` or :n:`t = @ident` + with :n:`@ident` not occurring in :g:`t`. Then it replaces :n:`@ident` by + :g:`t` everywhere in the goal (in the hypotheses and in the conclusion) and + clears :n:`@ident` and :g:`H` from the context. -This tactic applies to a goal that has :n:`@ident` in its context and (at -least) one hypothesis, say :g:`H`, of type :n:`@ident = t` or :n:`t = @ident` -with :n:`@ident` not occurring in :g:`t`. Then it replaces :n:`@ident` by -:g:`t` everywhere in the goal (in the hypotheses and in the conclusion) and -clears :n:`@ident` and :g:`H` from the context. - -If :n:`@ident` is a local definition of the form :n:`@ident := t`, it is also -unfolded and cleared. + If :n:`@ident` is a local definition of the form :n:`@ident := t`, it is also + unfolded and cleared. + .. note:: + + When several hypotheses have the form :n:`@ident = t` or :n:`t = @ident`, the + first one is used. -.. note:: - When several hypotheses have the form :n:`@ident = t` or :n:`t = @ident`, the - first one is used. + + If :g:`H` is itself dependent in the goal, it is replaced by the proof of + reflexivity of equality. + .. tacv:: subst {+ @ident} -.. note:: - If `H` is itself dependent in the goal, it is replaced by the proof of - reflexivity of equality. + This is equivalent to :n:`subst @ident`:sub:`1`:n:`; ...; subst @ident`:sub:`n`. + .. tacv:: subst -.. tacv:: subst {+ @ident} + This applies subst repeatedly from top to bottom to all identifiers of the + context for which an equality of the form :n:`@ident = t` or :n:`t = @ident` + or :n:`@ident := t` exists, with :n:`@ident` not occurring in ``t``. - This is equivalent to :n:`subst @ident`:sub:`1`:n:`; ...; subst @ident`:sub:`n`. + .. opt:: Regular Subst Tactic -.. tacv:: subst + This option controls the behavior of :tacn:`subst`. When it is + activated (it is by default), :tacn:`subst` also deals with the following corner cases: - This applies subst repeatedly from top to bottom to all identifiers of the - context for which an equality of the form :n:`@ident = t` or :n:`t = @ident` - or :n:`@ident := t` exists, with :n:`@ident` not occurring in `t`. + + A context with ordered hypotheses :n:`@ident`:sub:`1` :n:`= @ident`:sub:`2` + and :n:`@ident`:sub:`1` :n:`= t`, or :n:`t′ = @ident`:sub:`1`` with `t′` not + a variable, and no other hypotheses of the form :n:`@ident`:sub:`2` :n:`= u` + or :n:`u = @ident`:sub:`2`; without the option, a second call to + subst would be necessary to replace :n:`@ident`:sub:`2` by `t` or + `t′` respectively. + + The presence of a recursive equation which without the option would + be a cause of failure of :tacn:`subst`. + + A context with cyclic dependencies as with hypotheses :n:`@ident`:sub:`1` :n:`= f @ident`:sub:`2` + and :n:`@ident`:sub:`2` :n:`= g @ident`:sub:`1` which without the + option would be a cause of failure of :tacn:`subst`. - .. note:: + Additionally, it prevents a local definition such as :n:`@ident := t` to be + unfolded which otherwise it would exceptionally unfold in configurations + containing hypotheses of the form :n:`@ident = u`, or :n:`u′ = @ident` + with `u′` not a variable. Finally, it preserves the initial order of + hypotheses, which without the option it may break. + default. - The behavior of subst can be controlled using option ``Set Regular Subst - Tactic.`` When this option is activated, subst also deals with the - following corner cases: - + A context with ordered hypotheses :n:`@ident`:sub:`1` :n:`= @ident`:sub:`2` - and :n:`@ident`:sub:`1` :n:`= t`, or :n:`t′ = @ident`:sub:`1`` with `t′` not - a variable, and no other hypotheses of the form :n:`@ident`:sub:`2` :n:`= u` - or :n:`u = @ident`:sub:`2`; without the option, a second call to - subst would be necessary to replace :n:`@ident`:sub:`2` by `t` or - `t′` respectively. - + The presence of a recursive equation which without the option would - be a cause of failure of :tacn:`subst`. - + A context with cyclic dependencies as with hypotheses :n:`@ident`:sub:`1` :n:`= f @ident`:sub:`2` - and :n:`@ident`:sub:`2` :n:`= g @ident`:sub:`1` which without the - option would be a cause of failure of :tacn:`subst`. +.. tacn:: stepl @term + :name: stepl - Additionally, it prevents a local definition such as :n:`@ident := t` to be - unfolded which otherwise it would exceptionally unfold in configurations - containing hypotheses of the form :n:`@ident = u`, or :n:`u′ = @ident` - with `u′` not a variable. Finally, it preserves the initial order of - hypotheses, which without the option it may break. The option is on by - default. + This tactic is for chaining rewriting steps. It assumes a goal of the + form :n:`R @term @term` where ``R`` is a binary relation and relies on a + database of lemmas of the form :g:`forall x y z, R x y -> eq x z -> R z y` + where `eq` is typically a setoid equality. The application of :n:`stepl @term` + then replaces the goal by :n:`R @term @term` and adds a new goal stating + :n:`eq @term @term`. + .. cmd:: Declare Left Step @term -.. tacn:: stepl @term - :name: stepl + Adds :n:`@term` to the database used by :tacn:`stepl`. + The tactic is especially useful for parametric setoids which are not accepted + as regular setoids for :tacn:`rewrite` and :tacn:`setoid_replace` (see + :ref:`Generalizedrewriting`). -This tactic is for chaining rewriting steps. It assumes a goal of the -form :n:`R @term @term` where `R` is a binary relation and relies on a -database of lemmas of the form :g:`forall x y z, R x y -> eq x z -> R z y` -where `eq` is typically a setoid equality. The application of :n:`stepl @term` -then replaces the goal by :n:`R @term @term` and adds a new goal stating -:n:`eq @term @term`. + .. tacv:: stepl @term by @tactic -Lemmas are added to the database using the command ``Declare Left Step @term.`` -The tactic is especially useful for parametric setoids which are not accepted -as regular setoids for :tacn:`rewrite` and :tacn:`setoid_replace` (see -:ref:`TODO-27-Generalizedrewriting`). + This applies :n:`stepl @term` then applies :token:`tactic` to the second goal. -.. tacv:: stepl @term by tactic + .. tacv:: stepr @term stepr @term by tactic + :name: stepr - This applies :n:`stepl @term` then applies tactic to the second goal. + This behaves as :tacn:`stepl` but on the right-hand-side of the binary + relation. Lemmas are expected to be of the form + :g:`forall x y z, R x y -> eq y z -> R x z`. -.. tacv:: stepr @term stepr @term by tactic + .. cmd:: Declare Right Step @term - This behaves as :tacn:`stepl` but on the right-hand-side of the binary - relation. Lemmas are expected to be of the form :g:`forall x y z, R x y -> eq - y z -> R x z` and are registered using the command ``Declare Right Step - @term.`` + Adds :n:`@term` to the database used by :tacn:`stepr`. .. tacn:: change @term :name: change - This tactic applies to any goal. It implements the rule ``Conv`` given in - :ref:`TODO-4.4-Subtypingrules`. :g:`change U` replaces the current goal `T` - with `U` providing that `U` is well-formed and that `T` and `U` are - convertible. - -.. exn:: Not convertible + This tactic applies to any goal. It implements the rule ``Conv`` given in + :ref:`subtyping-rules`. :g:`change U` replaces the current goal `T` + with `U` providing that `U` is well-formed and that `T` and `U` are + convertible. + .. exn:: Not convertible. -.. tacv:: change @term with @term + .. tacv:: change @term with @term’ - This replaces the occurrences of :n:`@term` by :n:`@term` in the current goal. - The term :n:`@term` and :n:`@term` must be convertible. + This replaces the occurrences of :n:`@term` by :n:`@term’` in the current goal. + The term :n:`@term` and :n:`@term’` must be convertible. -.. tacv:: change @term at {+ @num} with @term + .. tacv:: change @term at {+ @num} with @term’ - This replaces the occurrences numbered :n:`{+ @num}` of :n:`@term by @term` - in the current goal. The terms :n:`@term` and :n:`@term` must be convertible. + This replaces the occurrences numbered :n:`{+ @num}` of :n:`@term` by :n:`@term’` + in the current goal. The terms :n:`@term` and :n:`@term’` must be convertible. -.. exn:: Too few occurrences + .. exn:: Too few occurrences. -.. tacv:: change @term in @ident -.. tacv:: change @term with @term in @ident -.. tacv:: change @term at {+ @num} with @term in @ident + .. tacv:: change @term {? {? at {+ @num}} with @term} in @ident - This applies the change tactic not to the goal but to the hypothesis :n:`@ident`. + This applies the :tacn:`change` tactic not to the goal but to the hypothesis :n:`@ident`. -See also: :ref:`Performing computations <performingcomputations>` + .. seealso:: :ref:`Performing computations <performingcomputations>` .. _performingcomputations: @@ -2637,7 +2692,7 @@ the conversion in hypotheses :n:`{+ @ident}`. the normalization of the goal according to the specified flags. In correspondence with the kinds of reduction considered in Coq namely :math:`\beta` (reduction of functional application), :math:`\delta` - (unfolding of transparent constants, see :ref:`TODO-6.10.2-Transparent`), + (unfolding of transparent constants, see :ref:`vernac-controlling-the-reduction-strategies`), :math:`\iota` (reduction of pattern-matching over a constructed term, and unfolding of :g:`fix` and :g:`cofix` expressions) and :math:`\zeta` (contraction of local definitions), the @@ -2649,7 +2704,7 @@ the conversion in hypotheses :n:`{+ @ident}`. second case the constant to unfold to all but the ones explicitly mentioned. Notice that the ``delta`` flag does not apply to variables bound by a let-in construction inside the :n:`@term` itself (use here the ``zeta`` flag). In - any cases, opaque constants are not unfolded (see :ref:`TODO-6.10.1-Opaque`). + any cases, opaque constants are not unfolded (see :ref:`vernac-controlling-the-reduction-strategies`). Normalization according to the flags is done by first evaluating the head of the expression into a *weak-head* normal form, i.e. until the @@ -2704,6 +2759,7 @@ the conversion in hypotheses :n:`{+ @ident}`. and :n:`lazy beta delta -{+ @qualid} iota zeta`. .. tacv:: vm_compute + :name: vm_compute This tactic evaluates the goal using the optimized call-by-value evaluation bytecode-based virtual machine described in :cite:`CompiledStrongReduction`. @@ -2713,6 +2769,7 @@ the conversion in hypotheses :n:`{+ @ident}`. reflection-based tactics. .. tacv:: native_compute + :name: native_compute This tactic evaluates the goal by compilation to Objective Caml as described in :cite:`FullReduction`. If Coq is running in native code, it can be @@ -2754,7 +2811,7 @@ the conversion in hypotheses :n:`{+ @ident}`. definition (say :g:`t`) and then reduces :g:`(t t`:sub:`1` :g:`... t`:sub:`n` :g:`)` according to :math:`\beta`:math:`\iota`:math:`\zeta`-reduction rules. -.. exn:: Not reducible +.. exn:: Not reducible. .. tacn:: hnf :name: hnf @@ -2768,7 +2825,7 @@ the conversion in hypotheses :n:`{+ @ident}`. :n:`hnf`. .. note:: - The :math:`\delta` rule only applies to transparent constants (see :ref:`TODO-6.10.1-Opaque` + The :math:`\delta` rule only applies to transparent constants (see :ref:`vernac-controlling-the-reduction-strategies` on transparency and opacity). .. tacn:: cbn @@ -2881,7 +2938,7 @@ the conversion in hypotheses :n:`{+ @ident}`. This applies ``simpl`` only to the :n:`{+ @num}` occurrences of the subterms matching :n:`@pattern` in the current goal. - .. exn:: Too few occurrences + .. exn:: Too few occurrences. .. tacv:: simpl @qualid .. tacv:: simpl @string @@ -2906,12 +2963,12 @@ the conversion in hypotheses :n:`{+ @ident}`. This tactic applies to any goal. The argument qualid must denote a defined transparent constant or local definition (see - :ref:`TODO-1.3.2-Definitions` and :ref:`TODO-6.10.2-Transparent`). The tactic + :ref:`gallina-definitions` and :ref:`vernac-controlling-the-reduction-strategies`). The tactic ``unfold`` applies the :math:`\delta` rule to each occurrence of the constant to which :n:`@qualid` refers in the current goal and then replaces it with its :math:`\beta`:math:`\iota`-normal form. -.. exn:: @qualid does not denote an evaluable constant +.. exn:: @qualid does not denote an evaluable constant. .. tacv:: unfold @qualid in @ident @@ -2928,9 +2985,9 @@ the conversion in hypotheses :n:`{+ @ident}`. The lists :n:`{+, @num}` specify the occurrences of :n:`@qualid` to be unfolded. Occurrences are located from left to right. - .. exn:: bad occurrence number of @qualid + .. exn:: Bad occurrence number of @qualid. - .. exn:: @qualid does not occur + .. exn:: @qualid does not occur. .. tacv:: unfold @string @@ -2942,7 +2999,7 @@ the conversion in hypotheses :n:`{+ @ident}`. This is variant of :n:`unfold @string` where :n:`@string` gets its interpretation from the scope bound to the delimiting key :n:`key` - instead of its default interpretation (see :ref:`TODO-12.2.2-Localinterpretationrulesfornotations`). + instead of its default interpretation (see :ref:`Localinterpretationrulesfornotations`). .. tacv:: unfold {+, qualid_or_string at {+, @num}} This is the most general form, where :n:`qualid_or_string` is either a @@ -3020,7 +3077,7 @@ Conversion tactics applied to hypotheses Example: :n:`unfold not in (Type of H1) (Type of H3)`. -.. exn:: No such hypothesis : ident. +.. exn:: No such hypothesis: @ident. .. _automation: @@ -3071,6 +3128,7 @@ hints of the database named core. to know what lemmas/assumptions were used. .. tacv:: debug auto + :name: debug auto Behaves like :tacn:`auto` but shows the tactics it tries to solve the goal, including failing paths. @@ -3090,7 +3148,9 @@ hints of the database named core. .. tacv:: trivial with * .. tacv:: trivial using {+ @lemma} .. tacv:: debug trivial + :name: debug trivial .. tacv:: info_trivial + :name: info_trivial .. tacv:: {? info_}trivial {? using {+ @lemma}} {? with {+ @ident}} .. note:: @@ -3103,7 +3163,7 @@ the :tacn:`auto` and :tacn:`trivial` tactics: .. opt:: Info Auto .. opt:: Debug Auto .. opt:: Info Trivial -.. opt:: Info Trivial +.. opt:: Debug Trivial See also: :ref:`The Hints Databases for auto and eauto <thehintsdatabasesforautoandeauto>` @@ -3123,7 +3183,7 @@ can solve such a goal: Goal forall P:nat -> Prop, P 0 -> exists n, P n. eauto. -Note that :tacn:`ex_intro` should be declared as a hint. +Note that ``ex_intro`` should be declared as a hint. .. tacv:: {? info_}eauto {? @num} {? using {+ @lemma}} {? with {+ @ident}} @@ -3169,7 +3229,9 @@ the processing of the rewriting rules. The rewriting rule bases are built with the ``Hint Rewrite vernacular`` command. -.. warn:: This tactic may loop if you build non terminating rewriting systems. +.. warning:: + + This tactic may loop if you build non terminating rewriting systems. .. tacv:: autorewrite with {+ @ident} using @tactic @@ -3200,7 +3262,8 @@ See also: :tacn:`autorewrite` for examples showing the use of this tactic. This tactic tries to solve the current goal by a number of standard closing steps. In particular, it tries to close the current goal using the closing tactics - :tacn:`trivial`, reflexivity, symmetry, contradiction and inversion of hypothesis. + :tacn:`trivial`, :tacn:`reflexivity`, :tacn:`symmetry`, :tacn:`contradiction` + and :tacn:`inversion` of hypothesis. If this fails, it tries introducing variables and splitting and-hypotheses, using the closing tactics afterwards, and splitting the goal using :tacn:`split` and recursing. @@ -3211,7 +3274,7 @@ See also: :tacn:`autorewrite` for examples showing the use of this tactic. .. tacv:: now @tactic :name: now - Run :n:`@tac` followed by ``easy``. This is a notation for :n:`@tactic; easy`. + Run :n:`@tactic` followed by :tacn:`easy`. This is a notation for :n:`@tactic; easy`. Controlling automation -------------------------- @@ -3221,225 +3284,245 @@ Controlling automation The hints databases for auto and eauto ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -The hints for ``auto`` and ``eauto`` are stored in databases. Each database -maps head symbols to a list of hints. One can use the command +The hints for :tacn:`auto` and :tacn:`eauto` are stored in databases. Each database +maps head symbols to a list of hints. .. cmd:: Print Hint @ident -to display the hints associated to the head symbol :n:`@ident` -(see :ref:`Print Hint <printhint>`). Each hint has a cost that is a nonnegative -integer, and an optional pattern. The hints with lower cost are tried first. A -hint is tried by ``auto`` when the conclusion of the current goal matches its -pattern or when it has no pattern. + Use this command + to display the hints associated to the head symbol :n:`@ident` + (see :ref:`Print Hint <printhint>`). Each hint has a cost that is a nonnegative + integer, and an optional pattern. The hints with lower cost are tried first. A + hint is tried by :tacn:`auto` when the conclusion of the current goal matches its + pattern or when it has no pattern. Creating Hint databases ``````````````````````` -One can optionally declare a hint database using the command ``Create -HintDb``. If a hint is added to an unknown database, it will be +One can optionally declare a hint database using the command +:cmd:`Create HintDb`. If a hint is added to an unknown database, it will be automatically created. -.. cmd:: Create HintDb @ident {? discriminated}. - -This command creates a new database named :n:`@ident`. The database is -implemented by a Discrimination Tree (DT) that serves as an index of -all the lemmas. The DT can use transparency information to decide if a -constant should be indexed or not (c.f. :ref:`The hints databases for auto and eauto <thehintsdatabasesforautoandeauto>`), -making the retrieval more efficient. The legacy implementation (the default one -for new databases) uses the DT only on goals without existentials (i.e., ``auto`` -goals), for non-Immediate hints and do not make use of transparency -hints, putting more work on the unification that is run after -retrieval (it keeps a list of the lemmas in case the DT is not used). -The new implementation enabled by the discriminated option makes use -of DTs in all cases and takes transparency information into account. -However, the order in which hints are retrieved from the DT may differ -from the order in which they were inserted, making this implementation -observationally different from the legacy one. +.. cmd:: Create HintDb @ident {? discriminated} + + This command creates a new database named :n:`@ident`. The database is + implemented by a Discrimination Tree (DT) that serves as an index of + all the lemmas. The DT can use transparency information to decide if a + constant should be indexed or not + (c.f. :ref:`The hints databases for auto and eauto <thehintsdatabasesforautoandeauto>`), + making the retrieval more efficient. The legacy implementation (the default one + for new databases) uses the DT only on goals without existentials (i.e., :tacn:`auto` + goals), for non-Immediate hints and do not make use of transparency + hints, putting more work on the unification that is run after + retrieval (it keeps a list of the lemmas in case the DT is not used). + The new implementation enabled by the discriminated option makes use + of DTs in all cases and takes transparency information into account. + However, the order in which hints are retrieved from the DT may differ + from the order in which they were inserted, making this implementation + observationally different from the legacy one. The general command to add a hint to some databases :n:`{+ @ident}` is -.. cmd:: Hint hint_definition : {+ @ident} +.. cmd:: Hint @hint_definition : {+ @ident} -**Variants:** + .. cmdv:: Hint @hint_definition -.. cmd:: Hint hint_definition + No database name is given: the hint is registered in the core database. - No database name is given: the hint is registered in the core database. + .. cmdv:: Local Hint @hint_definition : {+ @ident} -.. cmd:: Local Hint hint_definition : {+ @ident} + This is used to declare hints that must not be exported to the other modules + that require and import the current module. Inside a section, the option + Local is useless since hints do not survive anyway to the closure of + sections. - This is used to declare hints that must not be exported to the other modules - that require and import the current module. Inside a section, the option - Local is useless since hints do not survive anyway to the closure of - sections. + .. cmdv:: Local Hint @hint_definition -.. cmd:: Local Hint hint_definition + Idem for the core database. - Idem for the core database. + .. cmdv:: Hint Resolve @term {? | {? @num} {? @pattern}} + :name: Hint Resolve -The ``hint_definition`` is one of the following expressions: + This command adds :n:`simple apply @term` to the hint list with the head + symbol of the type of :n:`@term`. The cost of that hint is the number of + subgoals generated by :n:`simple apply @term` or :n:`@num` if specified. The + associated :n:`@pattern` is inferred from the conclusion of the type of + :n:`@term` or the given :n:`@pattern` if specified. In case the inferred type + of :n:`@term` does not start with a product the tactic added in the hint list + is :n:`exact @term`. In case this type can however be reduced to a type + starting with a product, the tactic :n:`simple apply @term` is also stored in + the hints list. If the inferred type of :n:`@term` contains a dependent + quantification on a variable which occurs only in the premisses of the type + and not in its conclusion, no instance could be inferred for the variable by + unification with the goal. In this case, the hint is added to the hint list + of :tacn:`eauto` instead of the hint list of auto and a warning is printed. A + typical example of a hint that is used only by :tacn:`eauto` is a transitivity + lemma. -+ :n:`Resolve @term {? | {? @num} {? @pattern}}` - This command adds :n:`simple apply @term` to the hint list with the head symbol of the type of - :n:`@term`. The cost of that hint is the number of subgoals generated by - :n:`simple apply @term` or :n:`@num` if specified. The associated :n:`@pattern` - is inferred from the conclusion of the type of :n:`@term` or the given - :n:`@pattern` if specified. In case the inferred type of :n:`@term` does not - start with a product the tactic added in the hint list is :n:`exact @term`. - In case this type can however be reduced to a type starting with a product, - the tactic :n:`simple apply @term` is also stored in the hints list. If the - inferred type of :n:`@term` contains a dependent quantification on a variable - which occurs only in the premisses of the type and not in its conclusion, no - instance could be inferred for the variable by unification with the goal. In - this case, the hint is added to the hint list of :tacn:`eauto` instead of the - hint list of auto and a warning is printed. A typical example of a hint that - is used only by ``eauto`` is a transitivity lemma. + .. exn:: @term cannot be used as a hint - .. exn:: @term cannot be used as a hint + The head symbol of the type of :n:`@term` is a bound variable such that + this tactic cannot be associated to a constant. - The head symbol of the type of :n:`@term` is a bound variable such that - this tactic cannot be associated to a constant. + .. cmdv:: Hint Resolve {+ @term} - **Variants:** + Adds each :n:`Hint Resolve @term`. - + :n:`Resolve {+ @term}` - Adds each :n:`Resolve @term`. + .. cmdv:: Hint Resolve -> @term - + :n:`Resolve -> @term` - Adds the left-to-right implication of an equivalence as a hint (informally - the hint will be used as :n:`apply <- @term`, although as mentionned - before, the tactic actually used is a restricted version of ``apply``). + Adds the left-to-right implication of an equivalence as a hint (informally + the hint will be used as :n:`apply <- @term`, although as mentionned + before, the tactic actually used is a restricted version of + :tacn:`apply`). - + :n:`Resolve <- @term` - Adds the right-to-left implication of an equivalence as a hint. + .. cmdv:: Resolve <- @term -+ :n:`Immediate @term` - This command adds :n:`simple apply @term; trivial` to the hint list associated - with the head symbol of the type of :n:`@ident` in the given database. This - tactic will fail if all the subgoals generated by :n:`simple apply @term` are - not solved immediately by the ``trivial`` tactic (which only tries tactics - with cost 0).This command is useful for theorems such as the symmetry of - equality or :g:`n+1=m+1 -> n=m` that we may like to introduce with a limited - use in order to avoid useless proof-search.The cost of this tactic (which - never generates subgoals) is always 1, so that it is not used by ``trivial`` - itself. + Adds the right-to-left implication of an equivalence as a hint. - .. exn:: @term cannot be used as a hint + .. cmdv:: Hint Immediate @term + :name: Hint Immediate - **Variants:** + This command adds :n:`simple apply @term; trivial` to the hint list associated + with the head symbol of the type of :n:`@ident` in the given database. This + tactic will fail if all the subgoals generated by :n:`simple apply @term` are + not solved immediately by the :tacn:`trivial` tactic (which only tries tactics + with cost 0).This command is useful for theorems such as the symmetry of + equality or :g:`n+1=m+1 -> n=m` that we may like to introduce with a limited + use in order to avoid useless proof-search. The cost of this tactic (which + never generates subgoals) is always 1, so that it is not used by :tacn:`trivial` + itself. - + :n:`Immediate {+ @term}` - Adds each :n:`Immediate @term`. + .. exn:: @term cannot be used as a hint -+ :n:`Constructors @ident` - If :n:`@ident` is an inductive type, this command adds all its constructors as - hints of type Resolve. Then, when the conclusion of current goal has the form - :n:`(@ident ...)`, ``auto`` will try to apply each constructor. + .. cmdv:: Immediate {+ @term} - .. exn:: @ident is not an inductive type + Adds each :n:`Hint Immediate @term`. - **Variants:** + .. cmdv:: Hint Constructors @ident + :name: Hint Constructors - + :n:`Constructors {+ @ident}` - Adds each :n:`Constructors @ident`. + If :n:`@ident` is an inductive type, this command adds all its constructors as + hints of type ``Resolve``. Then, when the conclusion of current goal has the form + :n:`(@ident ...)`, :tacn:`auto` will try to apply each constructor. -+ :n:`Unfold @qualid` - This adds the tactic :n:`unfold @qualid` to the hint list that will only be - used when the head constant of the goal is :n:`@ident`. - Its cost is 4. + .. exn:: @ident is not an inductive type - **Variants:** + .. cmdv:: Hint Constructors {+ @ident} - + :n:`Unfold {+ @ident}` - Adds each :n:`Unfold @ident`. + Adds each :n:`Hint Constructors @ident`. -+ :n:`Transparent`, :n:`Opaque @qualid` - This adds a transparency hint to the database, making :n:`@qualid` a - transparent or opaque constant during resolution. This information is used - during unification of the goal with any lemma in the database and inside the - discrimination network to relax or constrain it in the case of discriminated - databases. + .. cmdv:: Hint Unfold @qualid + :name: Hint Unfold - **Variants:** + This adds the tactic :n:`unfold @qualid` to the hint list that will only be + used when the head constant of the goal is :n:`@ident`. + Its cost is 4. + + .. cmdv:: Hint Unfold {+ @ident} + + Adds each :n:`Hint Unfold @ident`. + + .. cmdv:: Hint %( Transparent %| Opaque %) @qualid + :name: Hint ( Transparent | Opaque ) + + This adds a transparency hint to the database, making :n:`@qualid` a + transparent or opaque constant during resolution. This information is used + during unification of the goal with any lemma in the database and inside the + discrimination network to relax or constrain it in the case of discriminated + databases. + + .. cmdv:: Hint %( Transparent %| Opaque %) {+ @ident} - + :n:`Transparent`, :n:`Opaque {+ @ident}` Declares each :n:`@ident` as a transparent or opaque constant. -+ :n:`Extern @num {? @pattern} => tactic` - This hint type is to extend ``auto`` with tactics other than ``apply`` and - ``unfold``. For that, we must specify a cost, an optional :n:`@pattern` and a - :n:`tactic` to execute. Here is an example:: - - Hint Extern 4 (~(_ = _)) => discriminate. - - Now, when the head of the goal is a disequality, ``auto`` will try - discriminate if it does not manage to solve the goal with hints with a - cost less than 4. One can even use some sub-patterns of the pattern in - the tactic script. A sub-pattern is a question mark followed by an - identifier, like ``?X1`` or ``?X2``. Here is an example: - - .. example:: - .. coqtop:: reset all - - Require Import List. - Hint Extern 5 ({?X1 = ?X2} + {?X1 <> ?X2}) => generalize X1, X2; decide equality : eqdec. - Goal forall a b:list (nat * nat), {a = b} + {a <> b}. - Info 1 auto with eqdec. - -+ :n:`Cut @regexp` - - .. warning:: these hints currently only apply to typeclass - proof search and the ``typeclasses eauto`` tactic (:ref:`TODO-20.6.5-typeclasseseauto`). - - This command can be used to cut the proof-search tree according to a regular - expression matching paths to be cut. The grammar for regular expressions is - the following. Beware, there is no operator precedence during parsing, one can - check with ``Print HintDb`` to verify the current cut expression: - - .. productionlist:: `regexp` - e : ident hint or instance identifier - :|_ any hint - :| e\|e′ disjunction - :| e e′ sequence - :| e * Kleene star - :| emp empty - :| eps epsilon - :| ( e ) - - The `emp` regexp does not match any search path while `eps` - matches the empty path. During proof search, the path of - successive successful hints on a search branch is recorded, as a - list of identifiers for the hints (note Hint Extern’s do not have - an associated identifier). - Before applying any hint :n:`@ident` the current path `p` extended with - :n:`@ident` is matched against the current cut expression `c` associated to - the hint database. If matching succeeds, the hint is *not* applied. The - semantics of ``Hint Cut e`` is to set the cut expression to ``c | e``, the - initial cut expression being `emp`. - -+ :n:`Mode @qualid {* (+ | ! | -)}` - This sets an optional mode of use of the identifier :n:`@qualid`. When - proof-search faces a goal that ends in an application of :n:`@qualid` to - arguments :n:`@term ... @term`, the mode tells if the hints associated to - :n:`@qualid` can be applied or not. A mode specification is a list of n ``+``, - ``!`` or ``-`` items that specify if an argument of the identifier is to be - treated as an input (``+``), if its head only is an input (``!``) or an output - (``-``) of the identifier. For a mode to match a list of arguments, input - terms and input heads *must not* contain existential variables or be - existential variables respectively, while outputs can be any term. Multiple - modes can be declared for a single identifier, in that case only one mode - needs to match the arguments for the hints to be applied.The head of a term - is understood here as the applicative head, or the match or projection - scrutinee’s head, recursively, casts being ignored. ``Hint Mode`` is - especially useful for typeclasses, when one does not want to support default - instances and avoid ambiguity in general. Setting a parameter of a class as an - input forces proof-search to be driven by that index of the class, with ``!`` - giving more flexibility by allowing existentials to still appear deeper in the - index but not at its head. + .. cmdv:: Hint Extern @num {? @pattern} => @tactic + :name: Hint Extern -.. note:: - One can use an ``Extern`` hint with no pattern to do pattern-matching on - hypotheses using ``match goal`` with inside the tactic. + This hint type is to extend :tacn:`auto` with tactics other than :tacn:`apply` and + :tacn:`unfold`. For that, we must specify a cost, an optional :n:`@pattern` and a + :n:`@tactic` to execute. + + .. example:: + + .. coqtop:: in + + Hint Extern 4 (~(_ = _)) => discriminate. + + Now, when the head of the goal is a disequality, ``auto`` will try + discriminate if it does not manage to solve the goal with hints with a + cost less than 4. + + One can even use some sub-patterns of the pattern in + the tactic script. A sub-pattern is a question mark followed by an + identifier, like ``?X1`` or ``?X2``. Here is an example: + + .. example:: + + .. coqtop:: reset all + + Require Import List. + Hint Extern 5 ({?X1 = ?X2} + {?X1 <> ?X2}) => generalize X1, X2; decide equality : eqdec. + Goal forall a b:list (nat * nat), {a = b} + {a <> b}. + Info 1 auto with eqdec. + + .. cmdv:: Hint Cut @regexp + + .. warning:: + + These hints currently only apply to typeclass proof search and the + :tacn:`typeclasses eauto` tactic. + + This command can be used to cut the proof-search tree according to a regular + expression matching paths to be cut. The grammar for regular expressions is + the following. Beware, there is no operator precedence during parsing, one can + check with :cmd:`Print HintDb` to verify the current cut expression: + + .. productionlist:: `regexp` + e : ident hint or instance identifier + :| _ any hint + :| e\|e′ disjunction + :| e e′ sequence + :| e * Kleene star + :| emp empty + :| eps epsilon + :| ( e ) + + The `emp` regexp does not match any search path while `eps` + matches the empty path. During proof search, the path of + successive successful hints on a search branch is recorded, as a + list of identifiers for the hints (note Hint Extern’s do not have + an associated identifier). + Before applying any hint :n:`@ident` the current path `p` extended with + :n:`@ident` is matched against the current cut expression `c` associated to + the hint database. If matching succeeds, the hint is *not* applied. The + semantics of ``Hint Cut e`` is to set the cut expression to ``c | e``, the + initial cut expression being `emp`. + + .. cmdv:: Hint Mode @qualid {* (+ | ! | -)} + + This sets an optional mode of use of the identifier :n:`@qualid`. When + proof-search faces a goal that ends in an application of :n:`@qualid` to + arguments :n:`@term ... @term`, the mode tells if the hints associated to + :n:`@qualid` can be applied or not. A mode specification is a list of n ``+``, + ``!`` or ``-`` items that specify if an argument of the identifier is to be + treated as an input (``+``), if its head only is an input (``!``) or an output + (``-``) of the identifier. For a mode to match a list of arguments, input + terms and input heads *must not* contain existential variables or be + existential variables respectively, while outputs can be any term. Multiple + modes can be declared for a single identifier, in that case only one mode + needs to match the arguments for the hints to be applied.The head of a term + is understood here as the applicative head, or the match or projection + scrutinee’s head, recursively, casts being ignored. ``Hint Mode`` is + especially useful for typeclasses, when one does not want to support default + instances and avoid ambiguity in general. Setting a parameter of a class as an + input forces proof-search to be driven by that index of the class, with ``!`` + giving more flexibility by allowing existentials to still appear deeper in the + index but not at its head. + + .. note:: + + One can use an ``Extern`` hint with no pattern to do pattern-matching on + hypotheses using ``match goal`` with inside the tactic. Hint databases defined in the Coq standard library @@ -3521,7 +3604,7 @@ at every moment. (left to right). Notice that the rewriting bases are distinct from the ``auto`` hint bases and thatauto does not take them into account. - This command is synchronous with the section mechanism (see :ref:`TODO-2.4-Sectionmechanism`): + This command is synchronous with the section mechanism (see :ref:`section-mechanism`): when closing a section, all aliases created by ``Hint Rewrite`` in that section are lost. Conversely, when loading a module, all ``Hint Rewrite`` declarations at the global level of that module are loaded. @@ -3561,7 +3644,7 @@ described above: either they disappear at the end of a section scope, or they remain global forever. This causes a scalability issue, because hints coming from an unrelated part of the code may badly influence another development. It can be mitigated to some extent -thanks to the ``Remove Hints`` command (see :ref:`Remove Hints <removehints>`), +thanks to the :cmd:`Remove Hints` command, but this is a mere workaround and has some limitations (for instance, external hints cannot be removed). @@ -3569,73 +3652,70 @@ A proper way to fix this issue is to bind the hints to their module scope, as for most of the other objects Coq uses. Hints should only made available when the module they are defined in is imported, not just required. It is very difficult to change the historical behavior, as it would break a lot of scripts. -We propose a smooth transitional path by providing the ``Loose Hint Behavior`` +We propose a smooth transitional path by providing the :opt:`Loose Hint Behavior` option which accepts three flags allowing for a fine-grained handling of non-imported hints. -**Variants:** +.. opt:: Loose Hint Behavior %( "Lax" %| "Warn" %| "Strict" %) + :name: Loose Hint Behavior -.. cmd:: Set Loose Hint Behavior "Lax" + This option accepts three values, which control the behavior of hints w.r.t. + :cmd:`Import`: - This is the default, and corresponds to the historical behavior, that - is, hints defined outside of a section have a global scope. + - "Lax": this is the default, and corresponds to the historical behavior, + that is, hints defined outside of a section have a global scope. -.. cmd:: Set Loose Hint Behavior "Warn" + - "Warn": outputs a warning when a non-imported hint is used. Note that this + is an over-approximation, because a hint may be triggered by a run that + will eventually fail and backtrack, resulting in the hint not being + actually useful for the proof. - When set, it outputs a warning when a non-imported hint is used. Note that - this is an over-approximation, because a hint may be triggered by a run that - will eventually fail and backtrack, resulting in the hint not being actually - useful for the proof. + - "Strict": changes the behavior of an unloaded hint to a immediate fail + tactic, allowing to emulate an import-scoped hint mechanism. -.. cmd:: Set Loose Hint Behavior "Strict" - - When set, it changes the behavior of an unloaded hint to a immediate fail - tactic, allowing to emulate an import-scoped hint mechanism. +.. _tactics-implicit-automation: Setting implicit automation tactics ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -.. cmd:: Proof with tactic +.. cmd:: Proof with @tactic This command may be used to start a proof. It defines a default tactic to be used each time a tactic command ``tactic``:sub:`1` is ended by ``...``. In this case the tactic command typed by the user is equivalent to ``tactic``:sub:`1` ``;tactic``. -See also: Proof. in :ref:`TODO-7.1.4-Proofterm`. + See also: ``Proof.`` in :ref:`proof-editing-mode`. -**Variants:** -.. cmd:: Proof with tactic using {+ @ident} + .. cmdv:: Proof with tactic using {+ @ident} - Combines in a single line ``Proof with`` and ``Proof using``, see :ref:`TODO-7.1.5-Proofusing` + Combines in a single line ``Proof with`` and ``Proof using``, see :ref:`proof-editing-mode` -.. cmd:: Proof using {+ @ident} with tactic + .. cmdv:: Proof using {+ @ident} with @tactic - Combines in a single line ``Proof with`` and ``Proof using``, see :ref:`TODO-7.1.5-Proofusing` + Combines in a single line ``Proof with`` and ``Proof using``, see :ref:`proof-editing-mode` -.. cmd:: Declare Implicit Tactic tactic + .. cmd:: Declare Implicit Tactic @tactic - This command declares a tactic to be used to solve implicit arguments - that Coq does not know how to solve by unification. It is used every - time the term argument of a tactic has one of its holes not fully - resolved. + This command declares a tactic to be used to solve implicit arguments + that Coq does not know how to solve by unification. It is used every + time the term argument of a tactic has one of its holes not fully + resolved. -Here is an example: + .. example:: -.. example:: + .. coqtop:: all - .. coqtop:: all + Parameter quo : nat -> forall n:nat, n<>0 -> nat. + Notation "x // y" := (quo x y _) (at level 40). + Declare Implicit Tactic assumption. + Goal forall n m, m<>0 -> { q:nat & { r | q * m + r = n } }. + intros. + exists (n // m). - Parameter quo : nat -> forall n:nat, n<>0 -> nat. - Notation "x // y" := (quo x y _) (at level 40). - Declare Implicit Tactic assumption. - Goal forall n m, m<>0 -> { q:nat & { r | q * m + r = n } }. - intros. - exists (n // m). - - The tactic ``exists (n // m)`` did not fail. The hole was solved - by ``assumption`` so that it behaved as ``exists (quo n m H)``. + The tactic ``exists (n // m)`` did not fail. The hole was solved + by ``assumption`` so that it behaved as ``exists (quo n m H)``. .. _decisionprocedures: @@ -3680,11 +3760,12 @@ Therefore, the use of :tacn:`intros` in the previous proof is unnecessary. an instantiation of `x` is necessary. .. tacv:: dtauto + :name: dtauto - While :tacn:`tauto` recognizes inductively defined connectives isomorphic to - the standard connective ``and, prod, or, sum, False, Empty_set, unit, True``, - :tacn:`dtauto` recognizes also all inductive types with one constructors and - no indices, i.e. record-style connectives. + While :tacn:`tauto` recognizes inductively defined connectives isomorphic to + the standard connective ``and, prod, or, sum, False, Empty_set, unit, True``, + :tacn:`dtauto` recognizes also all inductive types with one constructors and + no indices, i.e. record-style connectives. .. tacn:: intuition @tactic :name: intuition @@ -3713,7 +3794,7 @@ and then uses :tacn:`auto` which completes the proof. Originally due to César Muñoz, these tactics (:tacn:`tauto` and :tacn:`intuition`) have been completely re-engineered by David Delahaye using -mainly the tactic language (see :ref:`TODO-9-thetacticlanguage`). The code is +mainly the tactic language (see :ref:`ltac`). The code is now much shorter and a significant increase in performance has been noticed. The general behavior with respect to dependent types, unfolding and introductions has slightly changed to get clearer semantics. This may lead to @@ -3721,26 +3802,20 @@ some incompatibilities. .. tacv:: intuition - Is equivalent to :g:`intuition auto with *`. + Is equivalent to :g:`intuition auto with *`. .. tacv:: dintuition + :name: dintuition - While :tacn:`intuition` recognizes inductively defined connectives - isomorphic to the standard connective ``and, prod, or, sum, False, - Empty_set, unit, True``, :tacn:`dintuition` recognizes also all inductive - types with one constructors and no indices, i.e. record-style connectives. - -Some aspects of the tactic :tacn:`intuition` can be controlled using options. -To avoid that inner negations which do not need to be unfolded are -unfolded, use: - -.. cmd:: Unset Intuition Negation Unfolding + While :tacn:`intuition` recognizes inductively defined connectives + isomorphic to the standard connective ``and``, ``prod``, ``or``, ``sum``, ``False``, + ``Empty_set``, ``unit``, ``True``, :tacn:`dintuition` recognizes also all inductive + types with one constructors and no indices, i.e. record-style connectives. +.. opt:: Intuition Negation Unfolding -To do that all negations of the goal are unfolded even inner ones -(this is the default), use: - -.. cmd:: Set Intuition Negation Unfolding + Controls whether :tacn:`intuition` unfolds inner negations which do not need + to be unfolded. This option is on by default. .. tacn:: rtauto :name: rtauto @@ -3764,14 +3839,18 @@ first- order reasoning, written by Pierre Corbineau. It is not restricted to usual logical connectives but instead may reason about any first-order class inductive definition. -The default tactic used by :tacn:`firstorder` when no rule applies is :g:`auto -with \*`, it can be reset locally or globally using the ``Set Firstorder -Solver`` tactic vernacular command and printed using ``Print Firstorder -Solver``. +.. opt:: Firstorder Solver @tactic + + The default tactic used by :tacn:`firstorder` when no rule applies is + :g:`auto with *`, it can be reset locally or globally using this option. + + .. cmd:: Print Firstorder Solver + + Prints the default tactic used by :tacn:`firstorder` when no rule applies. .. tacv:: firstorder @tactic - Tries to solve the goal with :n:`@tactic` when no logical rule may apply. + Tries to solve the goal with :n:`@tactic` when no logical rule may apply. .. tacv:: firstorder using {+ @qualid} @@ -3788,8 +3867,9 @@ Solver``. This combines the effects of the different variants of :tacn:`firstorder`. -Proof-search is bounded by a depth parameter which can be set by -typing the ``Set Firstorder Depth n`` vernacular command. +.. opt:: Firstorder Depth @num + + This option controls the proof-search depth bound. .. tacn:: congruence :name: congruence @@ -3830,11 +3910,12 @@ match against it. hypotheses using assert in order for :tacn:`congruence` to use them. .. tacv:: congruence with {+ @term} + :name: congruence with - Adds :n:`{+ @term}` to the pool of terms used by :tacn:`congruence`. This helps - in case you have partially applied constructors in your goal. + Adds :n:`{+ @term}` to the pool of terms used by :tacn:`congruence`. This helps + in case you have partially applied constructors in your goal. -.. exn:: I don’t know how to handle dependent equality +.. exn:: I don’t know how to handle dependent equality. The decision procedure managed to find a proof of the goal or of a discriminable equality but this proof could not be built in Coq because of @@ -3846,7 +3927,7 @@ match against it. arguments are supplied for some partially applied constructors. Any term of an appropriate type will allow the tactic to successfully solve the goal. Those additional arguments can be given to congruence by filling in the holes in the - terms given in the error message, using the with variant described above. + terms given in the error message, using the :tacn:`congruence with` variant described above. .. opt:: Congruence Verbose @@ -3865,7 +3946,7 @@ succeeds, and results in an error otherwise. This tactic checks whether its arguments are equal modulo alpha conversion and casts. -.. exn:: Not equal +.. exn:: Not equal. .. tacn:: unify @term @term :name: unify @@ -3873,12 +3954,12 @@ succeeds, and results in an error otherwise. This tactic checks whether its arguments are unifiable, potentially instantiating existential variables. -.. exn:: Not unifiable +.. exn:: Not unifiable. .. tacv:: unify @term @term with @ident Unification takes the transparency information defined in the hint database - :n:`@ident` into account (see :ref:`the hints databases for auto and eauto <the-hints-databases-for-auto-and-eauto>`). + :n:`@ident` into account (see :ref:`the hints databases for auto and eauto <thehintsdatabasesforautoandeauto>`). .. tacn:: is_evar @term :name: is_evar @@ -3887,7 +3968,7 @@ succeeds, and results in an error otherwise. variable. Existential variables are uninstantiated variables generated by :tacn:`eapply` and some other tactics. -.. exn:: Not an evar +.. exn:: Not an evar. .. tacn:: has_evar @term :name: has_evar @@ -3896,7 +3977,7 @@ succeeds, and results in an error otherwise. a subterm. Unlike context patterns combined with ``is_evar``, this tactic scans all subterms, including those under binders. -.. exn:: No evars +.. exn:: No evars. .. tacn:: is_var @term :name: is_var @@ -3904,7 +3985,7 @@ succeeds, and results in an error otherwise. This tactic checks whether its argument is a variable or hypothesis in the current goal context or in the opened sections. -.. exn:: Not a variable or hypothesis +.. exn:: Not a variable or hypothesis. .. _equality: @@ -3928,10 +4009,10 @@ solved by :tacn:`f_equal`. :name: reflexivity This tactic applies to a goal that has the form :g:`t=u`. It checks that `t` -and `u` are convertible and then solves the goal. It is equivalent to apply -:tacn:`refl_equal`. +and `u` are convertible and then solves the goal. It is equivalent to +``apply refl_equal``. -.. exn:: The conclusion is not a substitutive equation +.. exn:: The conclusion is not a substitutive equation. .. exn:: Unable to unify ... with ... @@ -4009,6 +4090,7 @@ symbol :g:`=`. .. tacv:: esimplify_eq @num .. tacv:: esimplify_eq @term {? with @bindings_list} + :name: esimplify_eq This works the same as ``simplify_eq`` but if the type of :n:`@term`, or the type of the hypothesis referred to by :n:`@num`, has uninstantiated @@ -4031,6 +4113,7 @@ symbol :g:`=`. :tacn:`injection` and :tacn:`inversion` tactics. .. tacv:: dependent rewrite <- @ident + :name: dependent rewrite <- Analogous to :tacn:`dependent rewrite ->` but uses the equality from right to left. @@ -4044,12 +4127,12 @@ Inversion :tacn:`functional inversion` is a tactic that performs inversion on hypothesis :n:`@ident` of the form :n:`@qualid {+ @term} = @term` or :n:`@term = @qualid {+ @term}` where :n:`@qualid` must have been defined using Function (see -:ref:`TODO-2.3-advancedrecursivefunctions`). Note that this tactic is only +:ref:`advanced-recursive-functions`). Note that this tactic is only available after a ``Require Import FunInd``. -.. exn:: Hypothesis @ident must contain at least one Function -.. exn:: Cannot find inversion information for hypothesis @ident +.. exn:: Hypothesis @ident must contain at least one Function. +.. exn:: Cannot find inversion information for hypothesis @ident. This error may be raised when some inversion lemma failed to be generated by Function. @@ -4077,10 +4160,10 @@ This kind of inversion has nothing to do with the tactic :tacn:`inversion` above. This tactic does :g:`change (@ident t)`, where `t` is a term built in order to ensure the convertibility. In other words, it does inversion of the function :n:`@ident`. This function must be a fixpoint on a simple recursive -datatype: see :ref:`TODO-10.3-quote` for the full details. +datatype: see :ref:`quote` for the full details. -.. exn:: quote: not a simple fixpoint +.. exn:: quote: not a simple fixpoint. Happens when quote is not able to perform inversion properly. @@ -4109,6 +4192,8 @@ using the ``Require Import`` command. Use ``classical_right`` to prove the right part of the disjunction with the assumption that the negation of left part holds. +.. _tactics-automatizing: + Automatizing ------------ @@ -4148,7 +4233,7 @@ formulas built with `~`, `\/`, `/\`, `->` on top of equalities, inequalities and disequalities on both the type :g:`nat` of natural numbers and :g:`Z` of binary integers. This tactic must be loaded by the command ``Require Import Omega``. See the additional documentation about omega -(see Chapter :ref:`TODO-21-omega`). +(see Chapter :ref:`omega`). .. tacn:: ring @@ -4168,7 +4253,7 @@ given in the conclusion of the goal by their normal forms. If no term is given, then the conclusion should be an equation and both hand sides are normalized. -See :ref:`TODO-Chapter-25-Theringandfieldtacticfamilies` for more information on +See :ref:`Theringandfieldtacticfamilies` for more information on the tactic and how to declare new ring structures. All declared field structures can be printed with the ``Print Rings`` command. @@ -4194,7 +4279,7 @@ denominators. So it produces an equation without division nor inverse. All of these 3 tactics may generate a subgoal in order to prove that denominators are different from zero. -See :ref:`TODO-Chapter-25-Theringandfieldtacticfamilies` for more information on the tactic and how to +See :ref:`Theringandfieldtacticfamilies` for more information on the tactic and how to declare new field structures. All declared field structures can be printed with the Print Fields command. @@ -4286,24 +4371,24 @@ This tactics reverses the list of the focused goals. This tactic moves all goals under focus to a shelf. While on the shelf, goals will not be focused on. They can be solved by unification, or they can be called back into focus with the command - :tacn:`Unshelve`. + :cmd:`Unshelve`. -.. tacv:: shelve_unifiable + .. tacv:: shelve_unifiable + :name: shelve_unifiable - Shelves only the goals under focus that are mentioned in other goals. - Goals that appear in the type of other goals can be solved by unification. + Shelves only the goals under focus that are mentioned in other goals. + Goals that appear in the type of other goals can be solved by unification. -.. example:: + .. example:: - .. coqtop:: all reset + .. coqtop:: all reset - Goal exists n, n=0. - refine (ex_intro _ _ _). - all:shelve_unifiable. - reflexivity. + Goal exists n, n=0. + refine (ex_intro _ _ _). + all: shelve_unifiable. + reflexivity. -.. tacn:: Unshelve - :name: Unshelve +.. cmd:: Unshelve This command moves all the goals on the shelf (see :tacn:`shelve`) from the shelf into focus, by appending them to the end of the current @@ -4334,11 +4419,11 @@ A simple example has more value than a long explanation: The tactics macros are synchronous with the Coq section mechanism: a tactic definition is deleted from the current environment when you -close the section (see also :ref:`TODO-2.4Sectionmechanism`) where it was +close the section (see also :ref:`section-mechanism`) where it was defined. If you want that a tactic macro defined in a module is usable in the modules that require it, you should put it outside of any section. -:ref:`TODO-9-Thetacticlanguage` gives examples of more complex +:ref:`ltac` gives examples of more complex user-defined tactics. .. [1] Actually, only the second subgoal will be generated since the diff --git a/doc/sphinx/proof-engine/vernacular-commands.rst b/doc/sphinx/proof-engine/vernacular-commands.rst new file mode 100644 index 0000000000..c37233734b --- /dev/null +++ b/doc/sphinx/proof-engine/vernacular-commands.rst @@ -0,0 +1,1242 @@ +.. include:: ../preamble.rst +.. include:: ../replaces.rst + +.. _vernacularcommands: + +Vernacular commands +============================= + +.. _displaying: + +Displaying +-------------- + + +.. _Print: + +.. cmd:: Print @qualid + :name: Print + + This command displays on the screen information about the declared or + defined object referred by :n:`@qualid`. + + Error messages: + + .. exn:: @qualid not a defined object. + + .. exn:: Universe instance should have length @num. + + .. exn:: This object does not support universe names. + + + .. cmdv:: Print Term @qualid + :name: Print Term + + This is a synonym of :cmd:`Print` :n:`@qualid` when :n:`@qualid` + denotes a global constant. + + .. cmdv:: Print {? Term } @qualid\@@name + + This locally renames the polymorphic universes of :n:`@qualid`. + An underscore means the raw universe is printed. + + +.. cmd:: About @qualid + :name: About + + This displays various information about the object + denoted by :n:`@qualid`: its kind (module, constant, assumption, inductive, + constructor, abbreviation, …), long name, type, implicit arguments and + argument scopes. It does not print the body of definitions or proofs. + + .. cmdv:: About @qualid\@@name + + This locally renames the polymorphic universes of :n:`@qualid`. + An underscore means the raw universe is printed. + + +.. cmd:: Print All + + This command displays information about the current state of the + environment, including sections and modules. + + .. cmdv:: Inspect @num + :name: Inspect + + This command displays the :n:`@num` last objects of the + current environment, including sections and modules. + + .. cmdv:: Print Section @ident + + The name :n:`@ident` should correspond to a currently open section, + this command displays the objects defined since the beginning of this + section. + + +.. _flags-options-tables: + +Flags, Options and Tables +----------------------------- + +|Coq| configurability is based on flags (e.g. :opt:`Printing All`), options +(e.g. :opt:`Printing Width`), or tables (e.g. :cmd:`Add Printing Record`). The +names of flags, options and tables are made of non-empty sequences of +identifiers (conventionally with capital initial letter). The general commands +handling flags, options and tables are given below. + +.. TODO : flag is not a syntax entry + +.. cmd:: Set @flag + + This command switches :n:`@flag` on. The original state of :n:`@flag` + is restored when the current module ends. + + .. cmdv:: Local Set @flag + + This command switches :n:`@flag` on. The original state + of :n:`@flag` is restored when the current *section* ends. + + .. cmdv:: Global Set @flag + + This command switches :n:`@flag` on. The original state + of :n:`@flag` is *not* restored at the end of the module. Additionally, if + set in a file, :n:`@flag` is switched on when the file is `Require`-d. + + .. cmdv:: Export Set @flag + + This command switches :n:`@flag` on. The original state + of :n:`@flag` is restored at the end of the current module, but :n:`@flag` + is switched on when this module is imported. + + +.. cmd:: Unset @flag + + This command switches :n:`@flag` off. The original state of + :n:`@flag` is restored when the current module ends. + + .. cmdv:: Local Unset @flag + + This command switches :n:`@flag` off. The original + state of :n:`@flag` is restored when the current *section* ends. + + .. cmdv:: Global Unset @flag + + This command switches :n:`@flag` off. The original + state of :n:`@flag` is *not* restored at the end of the module. Additionally, + if set in a file, :n:`@flag` is switched off when the file is `Require`-d. + + .. cmdv:: Export Unset @flag + + This command switches :n:`@flag` off. The original state + of :n:`@flag` is restored at the end of the current module, but :n:`@flag` + is switched off when this module is imported. + + +.. cmd:: Test @flag + + This command prints whether :n:`@flag` is on or off. + + +.. cmd:: Set @option @value + + This command sets :n:`@option` to :n:`@value`. The original value of ` option` is + restored when the current module ends. + + .. TODO : option and value are not syntax entries + + .. cmdv:: Local Set @option @value + + This command sets :n:`@option` to :n:`@value`. The + original value of :n:`@option` is restored at the end of the module. + + .. cmdv:: Global Set @option @value + + This command sets :n:`@option` to :n:`@value`. The + original value of :n:`@option` is *not* restored at the end of the module. + Additionally, if set in a file, :n:`@option` is set to value when the file + is `Require`-d. + + .. cmdv:: Export Set @option + + This command set :n:`@option` to :n:`@value`. The original state + of :n:`@option` is restored at the end of the current module, but :n:`@option` + is set to :n:`@value` when this module is imported. + + +.. cmd:: Unset @option + + This command turns off :n:`@option`. + + .. cmdv:: Local Unset @option + + This command turns off :n:`@option`. The original state of :n:`@option` + is restored when the current *section* ends. + + .. cmdv:: Global Unset @option + + This command turns off :n:`@option`. The original state of :n:`@option` + is *not* restored at the end of the module. Additionally, if unset in a file, + :n:`@option` is reset to its default value when the file is `Require`-d. + + .. cmdv:: Export Unset @option + + This command turns off :n:`@option`. The original state of :n:`@option` + is restored at the end of the current module, but :n:`@option` is set to + its default value when this module is imported. + + +.. cmd:: Test @option + + This command prints the current value of :n:`@option`. + + +.. TODO : table is not a syntax entry + +.. cmd:: Add @table @value + :name: Add `table` `value` + +.. cmd:: Remove @table @value + :name: Remove `table` `value` + +.. cmd:: Test @table @value + :name: Test `table` `value` + +.. cmd:: Test @table for @value + :name: Test `table` for `value` + +.. cmd:: Print Table @table + +These are general commands for tables. + + +.. cmd:: Print Options + + This command lists all available flags, options and tables. + + .. cmdv:: Print Tables + + This is a synonymous of :cmd:`Print Options`. + + +.. _requests-to-the-environment: + +Requests to the environment +------------------------------- + +.. cmd:: Check @term + + This command displays the type of :n:`@term`. When called in proof mode, the + term is checked in the local context of the current subgoal. + + + .. TODO : selector is not a syntax entry + + .. cmdv:: @selector: Check @term + + This variant specifies on which subgoal to perform typing + (see Section :ref:`invocation-of-tactics`). + + +.. TODO : convtactic is not a syntax entry + +.. cmd:: Eval @convtactic in @term + + This command performs the specified reduction on :n:`@term`, and displays + the resulting term with its type. The term to be reduced may depend on + hypothesis introduced in the first subgoal (if a proof is in + progress). + + See also: Section :ref:`performingcomputations`. + + +.. cmd:: Compute @term + + This command performs a call-by-value evaluation of term by using the + bytecode-based virtual machine. It is a shortcut for ``Eval vm_compute in`` + :n:`@term`. + + See also: Section :ref:`performingcomputations`. + + +.. cmd:: Print Assumptions @qualid + + This commands display all the assumptions (axioms, parameters and + variables) a theorem or definition depends on. Especially, it informs + on the assumptions with respect to which the validity of a theorem + relies. + + .. cmdv:: Print Opaque Dependencies @qualid + :name: Print Opaque Dependencies + + Displays the set of opaque constants :n:`@qualid` relies on in addition to + the assumptions. + + .. cmdv:: Print Transparent Dependencies @qualid + :name: Print Transparent Dependencies + + Displays the set of transparent constants :n:`@qualid` relies on + in addition to the assumptions. + + .. cmdv:: Print All Dependencies @qualid + :name: Print All Dependencies + + Displays all assumptions and constants :n:`@qualid` relies on. + + +.. cmd:: Search @qualid + + This command displays the name and type of all objects (hypothesis of + the current goal, theorems, axioms, etc) of the current context whose + statement contains :n:`@qualid`. This command is useful to remind the user + of the name of library lemmas. + + .. exn:: The reference @qualid was not found in the current environment. + + There is no constant in the environment named qualid. + + .. cmdv:: Search @string + + If :n:`@string` is a valid identifier, this command + displays the name and type of all objects (theorems, axioms, etc) of + the current context whose name contains string. If string is a + notation’s string denoting some reference :n:`@qualid` (referred to by its + main symbol as in `"+"` or by its notation’s string as in `"_ + _"` or + `"_ 'U' _"`, see Section :ref:`notations`), the command works like ``Search`` :n:`@qualid`. + + .. cmdv:: Search @string%@key + + The string string must be a notation or the main + symbol of a notation which is then interpreted in the scope bound to + the delimiting key :n:`@key` (see Section :ref:`LocalInterpretationRulesForNotations`). + + .. cmdv:: Search @term_pattern + + This searches for all statements or types of + definition that contains a subterm that matches the pattern + `term_pattern` (holes of the pattern are either denoted by `_` or by + `?ident` when non linear patterns are expected). + + .. cmdv:: Search { + [-]@term_pattern_string } + + where + :n:`@term_pattern_string` is a term_pattern, a string, or a string followed + by a scope delimiting key `%key`. This generalization of ``Search`` searches + for all objects whose statement or type contains a subterm matching + :n:`@term_pattern` (or :n:`@qualid` if :n:`@string` is the notation for a reference + qualid) and whose name contains all string of the request that + correspond to valid identifiers. If a term_pattern or a string is + prefixed by `-`, the search excludes the objects that mention that + term_pattern or that string. + + .. cmdv:: Search @term_pattern_string … @term_pattern_string inside {+ @qualid } + + This restricts the search to constructions defined in the modules + named by the given :n:`qualid` sequence. + + .. cmdv:: Search @term_pattern_string … @term_pattern_string outside {+ @qualid } + + This restricts the search to constructions not defined in the modules + named by the given :n:`qualid` sequence. + + .. cmdv:: @selector: Search [-]@term_pattern_string … [-]@term_pattern_string + + This specifies the goal on which to search hypothesis (see + Section :ref:`invocation-of-tactics`). + By default the 1st goal is searched. This variant can + be combined with other variants presented here. + + .. example:: + + .. coqtop:: in + + Require Import ZArith. + + .. coqtop:: all + + Search Z.mul Z.add "distr". + + Search "+"%Z "*"%Z "distr" -positive -Prop. + + Search (?x * _ + ?x * _)%Z outside OmegaLemmas. + + .. cmdv:: SearchAbout + :name: SearchAbout + + .. deprecated:: 8.5 + + Up to |Coq| version 8.4, :cmd:`Search` had the behavior of current + :cmd:`SearchHead` and the behavior of current :cmd:`Search` was obtained with + command :cmd:`SearchAbout`. For compatibility, the deprecated name + :cmd:`SearchAbout` can still be used as a synonym of :cmd:`Search`. For + compatibility, the list of objects to search when using :cmd:`SearchAbout` + may also be enclosed by optional ``[ ]`` delimiters. + + +.. cmd:: SearchHead @term + + This command displays the name and type of all hypothesis of the + current goal (if any) and theorems of the current context whose + statement’s conclusion has the form `(term t1 .. tn)`. This command is + useful to remind the user of the name of library lemmas. + + .. example:: + + .. coqtop:: reset all + + SearchHead le. + + SearchHead (@eq bool). + + .. cmdv:: SearchHead @term inside {+ @qualid } + + This restricts the search to constructions defined in the modules named + by the given :n:`qualid` sequence. + + .. cmdv:: SearchHead term outside {+ @qualid } + + This restricts the search to constructions not defined in the modules + named by the given :n:`qualid` sequence. + + .. exn:: Module/section @qualid not found. + + No module :n:`@qualid` has been required (see Section :ref:`compiled-files`). + + .. cmdv:: @selector: SearchHead @term + + This specifies the goal on which to + search hypothesis (see Section :ref:`invocation-of-tactics`). + By default the 1st goal is searched. This variant can be combined + with other variants presented here. + + .. note:: Up to |Coq| version 8.4, ``SearchHead`` was named ``Search``. + + +.. cmd:: SearchPattern @term + + This command displays the name and type of all hypothesis of the + current goal (if any) and theorems of the current context whose + statement’s conclusion or last hypothesis and conclusion matches the + expressionterm where holes in the latter are denoted by `_`. + It is a variant of :n:`Search @term_pattern` that does not look for subterms + but searches for statements whose conclusion has exactly the expected + form, or whose statement finishes by the given series of + hypothesis/conclusion. + + .. example:: + + .. coqtop:: in + + Require Import Arith. + + .. coqtop:: all + + SearchPattern (_ + _ = _ + _). + + SearchPattern (nat -> bool). + + SearchPattern (forall l : list _, _ l l). + + Patterns need not be linear: you can express that the same expression + must occur in two places by using pattern variables `?ident`. + + + .. example:: + + .. coqtop:: all + + SearchPattern (?X1 + _ = _ + ?X1). + + .. cmdv:: SearchPattern @term inside {+ @qualid } + + This restricts the search to constructions defined in the modules + named by the given :n:`qualid` sequence. + + .. cmdv:: SearchPattern @term outside {+ @qualid } + + This restricts the search to constructions not defined in the modules + named by the given :n:`qualid` sequence. + + .. cmdv:: @selector: SearchPattern @term + + This specifies the goal on which to + search hypothesis (see Section :ref:`invocation-of-tactics`). + By default the 1st goal is + searched. This variant can be combined with other variants presented + here. + + +.. cmd:: SearchRewrite @term + + This command displays the name and type of all hypothesis of the + current goal (if any) and theorems of the current context whose + statement’s conclusion is an equality of which one side matches the + expression term. Holes in term are denoted by “_”. + + .. example:: + + .. coqtop:: in + + Require Import Arith. + + .. coqtop:: all + + SearchRewrite (_ + _ + _). + + .. cmdv:: SearchRewrite term inside {+ @qualid } + + This restricts the search to constructions defined in the modules + named by the given :n:`qualid` sequence. + + .. cmdv:: SearchRewrite @term outside {+ @qualid } + + This restricts the search to constructions not defined in the modules + named by the given :n:`qualid` sequence. + + .. cmdv:: @selector: SearchRewrite @term + + This specifies the goal on which to + search hypothesis (see Section :ref:`invocation-of-tactics`). + By default the 1st goal is + searched. This variant can be combined with other variants presented + here. + +.. note:: + + .. cmd:: Add Search Blacklist @string + + For the ``Search``, ``SearchHead``, ``SearchPattern`` and ``SearchRewrite`` + queries, it is possible to globally filter the search results using this + command. A lemma whose fully-qualified name + contains any of the declared strings will be removed from the + search results. The default blacklisted substrings are ``_subproof`` and + ``Private_``. + + .. cmd:: Remove Search Blacklist @string + + This command allows expunging this blacklist. + + +.. cmd:: Locate @qualid + + This command displays the full name of objects whose name is a prefix + of the qualified identifier :n:`@qualid`, and consequently the |Coq| module in + which they are defined. It searches for objects from the different + qualified name spaces of |Coq|: terms, modules, Ltac, etc. + + .. example:: + + .. coqtop:: all + + Locate nat. + + Locate Datatypes.O. + + Locate Init.Datatypes.O. + + Locate Coq.Init.Datatypes.O. + + Locate I.Dont.Exist. + + .. cmdv:: Locate Term @qualid + + As Locate but restricted to terms. + + .. cmdv:: Locate Module @qualid + + As Locate but restricted to modules. + + .. cmdv:: Locate Ltac @qualid + + As Locate but restricted to tactics. + +See also: Section :ref:`locating-notations` + + +.. _loading-files: + +Loading files +----------------- + +|Coq| offers the possibility of loading different parts of a whole +development stored in separate files. Their contents will be loaded as +if they were entered from the keyboard. This means that the loaded +files are ASCII files containing sequences of commands for |Coq|’s +toplevel. This kind of file is called a *script* for |Coq|. The standard +(and default) extension of |Coq|’s script files is .v. + + +.. cmd:: Load @ident + + This command loads the file named :n:`ident`.v, searching successively in + each of the directories specified in the *loadpath*. (see Section + :ref:`libraries-and-filesystem`) + + Files loaded this way cannot leave proofs open, and the ``Load`` + command cannot be used inside a proof either. + + .. cmdv:: Load @string + + Loads the file denoted by the string :n:`@string`, where + string is any complete filename. Then the `~` and .. abbreviations are + allowed as well as shell variables. If no extension is specified, |Coq| + will use the default extension ``.v``. + + .. cmdv:: Load Verbose @ident + + .. cmdv:: Load Verbose @string + + Display, while loading, + the answers of |Coq| to each command (including tactics) contained in + the loaded file See also: Section :ref:`controlling-display`. + + .. exn:: Can’t find file @ident on loadpath. + + .. exn:: Load is not supported inside proofs. + + .. exn:: Files processed by Load cannot leave open proofs. + +.. _compiled-files: + +Compiled files +------------------ + +This section describes the commands used to load compiled files (see +Chapter :ref:`thecoqcommands` for documentation on how to compile a file). A compiled +file is a particular case of module called *library file*. + + +.. cmd:: Require @qualid + + This command looks in the loadpath for a file containing module :n:`@qualid` + and adds the corresponding module to the environment of |Coq|. As + library files have dependencies in other library files, the command + :cmd:`Require` :n:`@qualid` recursively requires all library files the module + qualid depends on and adds the corresponding modules to the + environment of |Coq| too. |Coq| assumes that the compiled files have been + produced by a valid |Coq| compiler and their contents are then not + replayed nor rechecked. + + To locate the file in the file system, :n:`@qualid` is decomposed under the + form `dirpath.ident` and the file `ident.vo` is searched in the physical + directory of the file system that is mapped in |Coq| loadpath to the + logical path dirpath (see Section :ref:`libraries-and-filesystem`). The mapping between + physical directories and logical names at the time of requiring the + file must be consistent with the mapping used to compile the file. If + several files match, one of them is picked in an unspecified fashion. + + + .. cmdv:: Require Import @qualid + :name: Require Import + + This loads and declares the module :n:`@qualid` + and its dependencies then imports the contents of :n:`@qualid` as described + :ref:`here <import_qualid>`. It does not import the modules on which + qualid depends unless these modules were themselves required in module + :n:`@qualid` + using :cmd:`Require Export`, as described below, or recursively required + through a sequence of :cmd:`Require Export`. If the module required has + already been loaded, :cmd:`Require Import` :n:`@qualid` simply imports it, as + :cmd:`Import` :n:`@qualid` would. + + .. cmdv:: Require Export @qualid + :name: Require Export + + This command acts as :cmd:`Require Import` :n:`@qualid`, + but if a further module, say `A`, contains a command :cmd:`Require Export` `B`, + then the command :cmd:`Require Import` `A` also imports the module `B.` + + .. cmdv:: Require [Import | Export] {+ @qualid } + + This loads the + modules named by the :n:`qualid` sequence and their recursive + dependencies. If + ``Import`` or ``Export`` is given, it also imports these modules and + all the recursive dependencies that were marked or transitively marked + as ``Export``. + + .. cmdv:: From @dirpath Require @qualid + + This command acts as :cmd:`Require`, but picks + any library whose absolute name is of the form dirpath.dirpath’.qualid + for some `dirpath’`. This is useful to ensure that the :n:`@qualid` library + comes from a given package by making explicit its absolute root. + + .. exn:: Cannot load qualid: no physical path bound to dirpath. + + .. exn:: Cannot find library foo in loadpath. + + The command did not find the + file foo.vo. Either foo.v exists but is not compiled or foo.vo is in a + directory which is not in your LoadPath (see Section :ref:`libraries-and-filesystem`). + + .. exn:: Compiled library @ident.vo makes inconsistent assumptions over library qualid. + + The command tried to load library file :n:`@ident`.vo that + depends on some specific version of library :n:`@qualid` which is not the + one already loaded in the current |Coq| session. Probably `ident.v` was + not properly recompiled with the last version of the file containing + module :n:`@qualid`. + + .. exn:: Bad magic number. + + The file `ident.vo` was found but either it is not a + |Coq| compiled module, or it was compiled with an incompatible + version of |Coq|. + + .. exn:: The file `ident.vo` contains library dirpath and not library dirpath’. + + The library file `dirpath’` is indirectly required by the + ``Require`` command but it is bound in the current loadpath to the + file `ident.vo` which was bound to a different library name `dirpath` at + the time it was compiled. + + + .. exn:: Require is not allowed inside a module or a module type. + + This command + is not allowed inside a module or a module type being defined. It is + meant to describe a dependency between compilation units. Note however + that the commands ``Import`` and ``Export`` alone can be used inside modules + (see Section :ref:`Import <import_qualid>`). + + + +See also: Chapter :ref:`thecoqcommands` + + +.. cmd:: Print Libraries + + This command displays the list of library files loaded in the + current |Coq| session. For each of these libraries, it also tells if it + is imported. + + +.. cmd:: Declare ML Module {+ @string } + + This commands loads the OCaml compiled files + with names given by the :n:`@string` sequence + (dynamic link). It is mainly used to load tactics dynamically. The + files are searched into the current OCaml loadpath (see the + command ``Add ML Path`` in Section :ref:`libraries-and-filesystem`). + Loading of OCaml files is only possible under the bytecode version of + ``coqtop`` (i.e. ``coqtop`` called with option ``-byte``, see chapter + :ref:`thecoqcommands`), or when |Coq| has been compiled with a + version of OCaml that supports native Dynlink (≥ 3.11). + + .. cmdv:: Local Declare ML Module {+ @string } + + This variant is not exported to the modules that import the module + where they occur, even if outside a section. + + .. exn:: File not found on loadpath: @string. + + .. exn:: Loading of ML object file forbidden in a native Coq. + + +.. cmd:: Print ML Modules + + This prints the name of all OCaml modules loaded with ``Declare + ML Module``. To know from where these module were loaded, the user + should use the command ``Locate File`` (see :ref:`here <locate-file>`) + + +.. _loadpath: + +Loadpath +------------ + +Loadpaths are preferably managed using |Coq| command line options (see +Section `libraries-and-filesystem`) but there remain vernacular commands to manage them +for practical purposes. Such commands are only meant to be issued in +the toplevel, and using them in source files is discouraged. + + +.. cmd:: Pwd + + This command displays the current working directory. + + +.. cmd:: Cd @string + + This command changes the current directory according to :n:`@string` which + can be any valid path. + + .. cmdv:: Cd + + Is equivalent to Pwd. + + +.. cmd:: Add LoadPath @string as @dirpath + + This command is equivalent to the command line option + ``-Q`` :n:`@string` :n:`@dirpath`. It adds the physical directory string to the current + |Coq| loadpath and maps it to the logical directory dirpath. + + .. cmdv:: Add LoadPath @string + + Performs as Add LoadPath :n:`@string` as :n:`@dirpath` but + for the empty directory path. + + +.. cmd:: Add Rec LoadPath @string as @dirpath + + This command is equivalent to the command line option + ``-R`` :n:`@string` :n:`@dirpath`. It adds the physical directory string and all its + subdirectories to the current |Coq| loadpath. + + .. cmdv:: Add Rec LoadPath @string + + Works as :cmd:`Add Rec LoadPath` :n:`@string` as :n:`@dirpath` but for the empty + logical directory path. + + +.. cmd:: Remove LoadPath @string + + This command removes the path :n:`@string` from the current |Coq| loadpath. + + +.. cmd:: Print LoadPath + + This command displays the current |Coq| loadpath. + + .. cmdv:: Print LoadPath @dirpath + + Works as :cmd:`Print LoadPath` but displays only + the paths that extend the :n:`@dirpath` prefix. + + +.. cmd:: Add ML Path @string + + This command adds the path :n:`@string` to the current OCaml + loadpath (see the command `Declare ML Module`` in Section :ref:`compiled-files`). + + +.. cmd:: Add Rec ML Path @string + + This command adds the directory :n:`@string` and all its subdirectories to + the current OCaml loadpath (see the command :cmd:`Declare ML Module`). + + +.. cmd:: Print ML Path @string + + This command displays the current OCaml loadpath. This + command makes sense only under the bytecode version of ``coqtop``, i.e. + using option ``-byte`` + (see the command Declare ML Module in Section :ref:`compiled-files`). + +.. _locate-file: + +.. cmd:: Locate File @string + + This command displays the location of file string in the current + loadpath. Typically, string is a .cmo or .vo or .v file. + + +.. cmd:: Locate Library @dirpath + + This command gives the status of the |Coq| module dirpath. It tells if + the module is loaded and if not searches in the load path for a module + of logical name :n:`@dirpath`. + + +.. _backtracking: + +Backtracking +---------------- + +The backtracking commands described in this section can only be used +interactively, they cannot be part of a vernacular file loaded via +``Load`` or compiled by ``coqc``. + + +.. cmd:: Reset @ident + + This command removes all the objects in the environment since :n:`@ident` + was introduced, including :n:`@ident`. :n:`@ident` may be the name of a defined or + declared object as well as the name of a section. One cannot reset + over the name of a module or of an object inside a module. + + .. exn:: @ident: no such entry. + + .. cmdv:: Reset Initial + + Goes back to the initial state, just after the start + of the interactive session. + + +.. cmd:: Back + + This command undoes all the effects of the last vernacular command. + Commands read from a vernacular file via a :cmd:`Load` are considered as a + single command. Proof management commands are also handled by this + command (see Chapter :ref:`proofhandling`). For that, Back may have to undo more than + one command in order to reach a state where the proof management + information is available. For instance, when the last command is a + :cmd:`Qed`, the management information about the closed proof has been + discarded. In this case, :cmd:`Back` will then undo all the proof steps up to + the statement of this proof. + + .. cmdv:: Back @num + + Undo :n:`@num` vernacular commands. As for Back, some extra + commands may be undone in order to reach an adequate state. For + instance Back :n:`@num` will not re-enter a closed proof, but rather go just + before that proof. + + .. exn:: Invalid backtrack. + + The user wants to undo more commands than available in the history. + +.. cmd:: BackTo @num + + This command brings back the system to the state labeled :n:`@num`, + forgetting the effect of all commands executed after this state. The + state label is an integer which grows after each successful command. + It is displayed in the prompt when in -emacs mode. Just as :cmd:`Back` (see + above), the :cmd:`BackTo` command now handles proof states. For that, it may + have to undo some extra commands and end on a state `num′ ≤ num` if + necessary. + + .. cmdv:: Backtrack @num @num @num + :name: Backtrack + + .. deprecated:: 8.4 + + :cmd:`Backtrack` is a *deprecated* form of + :cmd:`BackTo` which allows explicitly manipulating the proof environment. The + three numbers represent the following: + + + *first number* : State label to reach, as for :cmd:`BackTo`. + + *second number* : *Proof state number* to unbury once aborts have been done. + |Coq| will compute the number of :cmd:`Undo` to perform (see Chapter :ref:`proofhandling`). + + *third number* : Number of :cmd:`Abort` to perform, i.e. the number of currently + opened nested proofs that must be canceled (see Chapter :ref:`proofhandling`). + + .. exn:: Invalid backtrack. + + The destination state label is unknown. + + +.. _quitting-and-debugging: + +Quitting and debugging +-------------------------- + + +.. cmd:: Quit + + This command permits to quit |Coq|. + + +.. cmd:: Drop + + This is used mostly as a debug facility by |Coq|’s implementors and does + not concern the casual user. This command permits to leave |Coq| + temporarily and enter the OCaml toplevel. The OCaml + command: + + :: + + #use "include";; + + adds the right loadpaths and loads some toplevel printers for all + abstract types of |Coq|- section_path, identifiers, terms, judgments, …. + You can also use the file base_include instead, that loads only the + pretty-printers for section_paths and identifiers. You can return back + to |Coq| with the command: + + :: + + go();; + + .. warning:: + + #. It only works with the bytecode version of |Coq| (i.e. `coqtop.byte`, + see Section `interactive-use`). + #. You must have compiled |Coq| from the source package and set the + environment variable COQTOP to the root of your copy of the sources + (see Section `customization-by-environment-variables`). + + +.. TODO : command is not a syntax entry + +.. cmd:: Time @command + + This command executes the vernacular command :n:`@command` and displays the + time needed to execute it. + + +.. cmd:: Redirect @string @command + + This command executes the vernacular command :n:`@command`, redirecting its + output to ":n:`@string`.out". + + +.. cmd:: Timeout @num @command + + This command executes the vernacular command :n:`@command`. If the command + has not terminated after the time specified by the :n:`@num` (time + expressed in seconds), then it is interrupted and an error message is + displayed. + + .. opt:: Default Timeout @num + + This option controls a default timeout for subsequent commands, as if they + were passed to a :cmd:`Timeout` command. Commands already starting by a + :cmd:`Timeout` are unaffected. + + +.. cmd:: Fail @command + + For debugging scripts, sometimes it is desirable to know + whether a command or a tactic fails. If the given :n:`@command` + fails, the ``Fail`` statement succeeds, without changing the proof + state, and in interactive mode, the system + prints a message confirming the failure. + If the given :n:`@command` succeeds, the statement is an error, and + it prints a message indicating that the failure did not occur. + + .. exn:: The command has not failed! + + +.. _controlling-display: + +Controlling display +----------------------- + +.. opt:: Silent + + This option controls the normal displaying. + +.. opt:: Warnings "{+, {? %( - %| + %) } @ident }" + + This option configures the display of warnings. It is experimental, and + expects, between quotes, a comma-separated list of warning names or + categories. Adding - in front of a warning or category disables it, adding + + makes it an error. It is possible to use the special categories all and + default, the latter containing the warnings enabled by default. The flags are + interpreted from left to right, so in case of an overlap, the flags on the + right have higher priority, meaning that `A,-A` is equivalent to `-A`. + +.. opt:: Search Output Name Only + + This option restricts the output of search commands to identifier names; + turning it on causes invocations of :cmd:`Search`, :cmd:`SearchHead`, + :cmd:`SearchPattern`, :cmd:`SearchRewrite` etc. to omit types from their + output, printing only identifiers. + +.. opt:: Printing Width @num + :name: Printing Width + + This command sets which left-aligned part of the width of the screen is used + for display. At the time of writing this documentation, the default value + is 78. + +.. opt:: Printing Depth @num + :name: Printing Depth + + This option controls the nesting depth of the formatter used for pretty- + printing. Beyond this depth, display of subterms is replaced by dots. At the + time of writing this documentation, the default value is 50. + +.. opt:: Printing Compact Contexts + + This option controls the compact display mode for goals contexts. When on, + the printer tries to reduce the vertical size of goals contexts by putting + several variables (even if of different types) on the same line provided it + does not exceed the printing width (see :opt:`Printing Width`). At the time + of writing this documentation, it is off by default. + +.. opt:: Printing Unfocused + + This option controls whether unfocused goals are displayed. Such goals are + created by focusing other goals with bullets (see :ref:`bullets` or + :ref:`curly braces <curly-braces>`). It is off by default. + +.. opt:: Printing Dependent Evars Line + + This option controls the printing of the “(dependent evars: …)” line when + ``-emacs`` is passed. + + +.. _vernac-controlling-the-reduction-strategies: + +Controlling the reduction strategies and the conversion algorithm +---------------------------------------------------------------------- + + +|Coq| provides reduction strategies that the tactics can invoke and two +different algorithms to check the convertibility of types. The first +conversion algorithm lazily compares applicative terms while the other +is a brute-force but efficient algorithm that first normalizes the +terms before comparing them. The second algorithm is based on a +bytecode representation of terms similar to the bytecode +representation used in the ZINC virtual machine :cite:`Leroy90`. It is +especially useful for intensive computation of algebraic values, such +as numbers, and for reflection-based tactics. The commands to fine- +tune the reduction strategies and the lazy conversion algorithm are +described first. + +.. cmd:: Opaque {+ @qualid } + + This command has an effect on unfoldable constants, i.e. on constants + defined by :cmd:`Definition` or :cmd:`Let` (with an explicit body), or by a command + assimilated to a definition such as :cmd:`Fixpoint`, :cmd:`Program Definition`, etc, + or by a proof ended by :cmd:`Defined`. The command tells not to unfold the + constants in the :n:`@qualid` sequence in tactics using δ-conversion (unfolding + a constant is replacing it by its definition). + + :cmd:`Opaque` has also an effect on the conversion algorithm of |Coq|, telling + it to delay the unfolding of a constant as much as possible when |Coq| + has to check the conversion (see Section :ref:`conversion-rules`) of two distinct + applied constants. + + .. cmdv:: Global Opaque {+ @qualid } + :name: Global Opaque + + The scope of :cmd:`Opaque` is limited to the current section, or current + file, unless the variant :cmd:`Global Opaque` is used. + + See also: sections :ref:`performingcomputations`, :ref:`tactics-automatizing`, + :ref:`proof-editing-mode` + + .. exn:: The reference @qualid was not found in the current environment. + + There is no constant referred by :n:`@qualid` in the environment. + Nevertheless, if you asked :cmd:`Opaque` `foo` `bar` and if `bar` does + not exist, `foo` is set opaque. + +.. cmd:: Transparent {+ @qualid } + + This command is the converse of :cmd:`Opaque` and it applies on unfoldable + constants to restore their unfoldability after an Opaque command. + + Note in particular that constants defined by a proof ended by Qed are + not unfoldable and Transparent has no effect on them. This is to keep + with the usual mathematical practice of *proof irrelevance*: what + matters in a mathematical development is the sequence of lemma + statements, not their actual proofs. This distinguishes lemmas from + the usual defined constants, whose actual values are of course + relevant in general. + + .. cmdv:: Global Transparent {+ @qualid } + :name: Global Transparent + + The scope of Transparent is limited to the current section, or current + file, unless the variant :cmd:`Global Transparent` is + used. + + .. exn:: The reference @qualid was not found in the current environment. + + There is no constant referred by :n:`@qualid` in the environment. + + See also: sections :ref:`performingcomputations`, + :ref:`tactics-automatizing`, :ref:`proof-editing-mode` + +.. _vernac-strategy: + +.. cmd:: Strategy @level [ {+ @qualid } ] + + This command generalizes the behavior of Opaque and Transparent + commands. It is used to fine-tune the strategy for unfolding + constants, both at the tactic level and at the kernel level. This + command associates a level to the qualified names in the :n:`@qualid` + sequence. Whenever two + expressions with two distinct head constants are compared (for + instance, this comparison can be triggered by a type cast), the one + with lower level is expanded first. In case of a tie, the second one + (appearing in the cast type) is expanded. + + Levels can be one of the following (higher to lower): + + + ``opaque`` : level of opaque constants. They cannot be expanded by + tactics (behaves like +∞, see next item). + + :n:`@num` : levels indexed by an integer. Level 0 corresponds to the + default behavior, which corresponds to transparent constants. This + level can also be referred to as transparent. Negative levels + correspond to constants to be expanded before normal transparent + constants, while positive levels correspond to constants to be + expanded after normal transparent constants. + + ``expand`` : level of constants that should be expanded first (behaves + like −∞) + + .. cmdv:: Local Strategy @level [ {+ @qualid } ] + + These directives survive section and module closure, unless the + command is prefixed by ``Local``. In the latter case, the behavior + regarding sections and modules is the same as for the :cmd:`Transparent` and + :cmd:`Opaque` commands. + + +.. cmd:: Print Strategy @qualid + + This command prints the strategy currently associated to :n:`@qualid`. It + fails if :n:`@qualid` is not an unfoldable reference, that is, neither a + variable nor a constant. + + .. exn:: The reference is not unfoldable. + + .. cmdv:: Print Strategies + + Print all the currently non-transparent strategies. + + +.. cmd:: Declare Reduction @ident := @convtactic + + This command allows giving a short name to a reduction expression, for + instance lazy beta delta [foo bar]. This short name can then be used + in ``Eval`` :n:`@ident` ``in`` ... or ``eval`` directives. This command + accepts the + Local modifier, for discarding this reduction name at the end of the + file or module. For the moment the name cannot be qualified. In + particular declaring the same name in several modules or in several + functor applications will be refused if these declarations are not + local. The name :n:`@ident` cannot be used directly as an Ltac tactic, but + nothing prevents the user to also perform a + ``Ltac`` `ident` ``:=`` `convtactic`. + + See also: sections :ref:`performingcomputations` + + +.. _controlling-locality-of-commands: + +Controlling the locality of commands +----------------------------------------- + + +.. cmd:: Local @command +.. cmd:: Global @command + +Some commands support a Local or Global prefix modifier to control the +scope of their effect. There are four kinds of commands: + + ++ Commands whose default is to extend their effect both outside the + section and the module or library file they occur in. For these + commands, the Local modifier limits the effect of the command to the + current section or module it occurs in. As an example, the :cmd:`Coercion` + and :cmd:`Strategy` commands belong to this category. ++ Commands whose default behavior is to stop their effect at the end + of the section they occur in but to extent their effect outside the module or + library file they occur in. For these commands, the Local modifier limits the + effect of the command to the current module if the command does not occur in a + section and the Global modifier extends the effect outside the current + sections and current module if the command occurs in a section. As an example, + the :cmd:`Arguments`, :cmd:`Ltac` or :cmd:`Notation` commands belong + to this category. Notice that a subclass of these commands do not support + extension of their scope outside sections at all and the Global is not + applicable to them. ++ Commands whose default behavior is to stop their effect at the end + of the section or module they occur in. For these commands, the ``Global`` + modifier extends their effect outside the sections and modules they + occurs in. The :cmd:`Transparent` and :cmd:`Opaque` + (see Section :ref:`vernac-controlling-the-reduction-strategies`) commands + belong to this category. ++ Commands whose default behavior is to extend their effect outside + sections but not outside modules when they occur in a section and to + extend their effect outside the module or library file they occur in + when no section contains them.For these commands, the Local modifier + limits the effect to the current section or module while the Global + modifier extends the effect outside the module even when the command + occurs in a section. The :cmd:`Set` and :cmd:`Unset` commands belong to this + category. diff --git a/doc/sphinx/replaces.rst b/doc/sphinx/replaces.rst index 1b2e172216..28a04f90ce 100644 --- a/doc/sphinx/replaces.rst +++ b/doc/sphinx/replaces.rst @@ -35,7 +35,9 @@ .. |ident_n,1| replace:: `ident`\ :math:`_{n,1}` .. |ident_n,k_n| replace:: `ident`\ :math:`_{n,k_n}` .. |ident_n| replace:: `ident`\ :math:`_{n}` +.. |Latex| replace:: :smallcaps:`LaTeX` .. |L_tac| replace:: `L`:sub:`tac` +.. |Ltac| replace:: `L`:sub:`tac` .. |ML| replace:: :smallcaps:`ML` .. |mod_0| replace:: `mod`\ :math:`_{0}` .. |mod_1| replace:: `mod`\ :math:`_{1}` @@ -54,7 +56,7 @@ .. |module_type_n| replace:: `module_type`\ :math:`_{n}` .. |N| replace:: ``N`` .. |nat| replace:: ``nat`` -.. |Ocaml| replace:: :smallcaps:`OCaml` +.. |OCaml| replace:: :smallcaps:`OCaml` .. |p_1| replace:: `p`\ :math:`_{1}` .. |p_i| replace:: `p`\ :math:`_{i}` .. |p_n| replace:: `p`\ :math:`_{n}` diff --git a/doc/sphinx/user-extensions/proof-schemes.rst b/doc/sphinx/user-extensions/proof-schemes.rst index 583b73e53d..838926d651 100644 --- a/doc/sphinx/user-extensions/proof-schemes.rst +++ b/doc/sphinx/user-extensions/proof-schemes.rst @@ -3,6 +3,8 @@ Proof schemes =============== +.. _proofschemes-induction-principles: + Generation of induction principles with ``Scheme`` -------------------------------------------------------- @@ -10,7 +12,7 @@ The ``Scheme`` command is a high-level tool for generating automatically (possibly mutual) induction principles for given types and sorts. Its syntax follows the schema: -.. cmd:: Scheme ident := Induction for ident' Sort sort {* with ident := Induction for ident' Sort sort} +.. cmd:: Scheme @ident := Induction for @ident Sort sort {* with @ident := Induction for @ident Sort sort} where each `ident'ᵢ` is a different inductive type identifier belonging to the same package of mutual inductive definitions. This @@ -18,17 +20,18 @@ command generates the `identᵢ`s to be mutually recursive definitions. Each term `identᵢ` proves a general principle of mutual induction for objects in type `identᵢ`. -.. cmdv:: Scheme ident := Minimality for ident' Sort sort {* with ident := Minimality for ident' Sort sort} +.. cmdv:: Scheme @ident := Minimality for @ident Sort sort {* with @ident := Minimality for @ident' Sort sort} Same as before but defines a non-dependent elimination principle more natural in case of inductively defined relations. -.. cmdv:: Scheme Equality for ident +.. cmdv:: Scheme Equality for @ident + :name: Scheme Equality Tries to generate a Boolean equality and a proof of the decidability of the usual equality. If `ident` involves some other inductive types, their equality has to be defined first. -.. cmdv:: Scheme Induction for ident Sort sort {* with Induction for ident Sort sort} +.. cmdv:: Scheme Induction for @ident Sort sort {* with Induction for @ident Sort sort} If you do not provide the name of the schemes, they will be automatically computed from the sorts involved (works also with Minimality). @@ -101,26 +104,34 @@ induction for objects in type `identᵢ`. Automatic declaration of schemes ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -It is possible to deactivate the automatic declaration of the -induction principles when defining a new inductive type with the -``Unset Elimination Schemes`` command. It may be reactivated at any time with -``Set Elimination Schemes``. - -The types declared with the keywords ``Variant`` (see :ref:`TODO-1.3.3`) and ``Record`` -(see :ref:`Record Types <record-types>`) do not have an automatic declaration of the induction -principles. It can be activated with the command -``Set Nonrecursive Elimination Schemes``. It can be deactivated again with -``Unset Nonrecursive Elimination Schemes``. - -In addition, the ``Case Analysis Schemes`` flag governs the generation of -case analysis lemmas for inductive types, i.e. corresponding to the -pattern-matching term alone and without fixpoint. -You can also activate the automatic declaration of those Boolean -equalities (see the second variant of ``Scheme``) with respectively the -commands ``Set Boolean Equality Schemes`` and ``Set Decidable Equality -Schemes``. However you have to be careful with this option since Coq may -now reject well-defined inductive types because it cannot compute a -Boolean equality for them. +.. opt:: Elimination Schemes + + It is possible to deactivate the automatic declaration of the + induction principles when defining a new inductive type with the + ``Unset Elimination Schemes`` command. It may be reactivated at any time with + ``Set Elimination Schemes``. + +.. opt:: Nonrecursive Elimination Schemes + + This option controls whether types declared with the keywords :cmd:`Variant` and + :cmd:`Record` get an automatic declaration of the induction principles. + +.. opt:: Case Analysis Schemes + + This flag governs the generation of case analysis lemmas for inductive types, + i.e. corresponding to the pattern-matching term alone and without fixpoint. + +.. opt:: Boolean Equality Schemes + +.. opt:: Decidable Equality Schemes + + These flags control the automatic declaration of those Boolean equalities (see + the second variant of ``Scheme``). + +.. warning:: + + You have to be careful with this option since Coq may now reject well-defined + inductive types because it cannot compute a Boolean equality for them. .. opt:: Rewriting Schemes @@ -133,7 +144,7 @@ The ``Combined Scheme`` command is a tool for combining induction principles generated by the ``Scheme command``. Its syntax follows the schema : -.. cmd:: Combined Scheme ident from {+, ident} +.. cmd:: Combined Scheme @ident from {+, ident} where each identᵢ after the ``from`` is a different inductive principle that must belong to the same package of mutual inductive principle definitions. @@ -163,6 +174,8 @@ concluded by the conjunction of their conclusions. Check tree_forest_mutind. +.. _functional-scheme: + Generation of induction principles with ``Functional`` ``Scheme`` ----------------------------------------------------------------- @@ -172,7 +185,7 @@ generating automatically induction principles corresponding to available via ``Require Import FunInd``. Its syntax then follows the schema: -.. cmd:: Functional Scheme ident := Induction for ident' Sort sort {* with ident := Induction for ident' Sort sort} +.. cmd:: Functional Scheme @ident := Induction for ident' Sort sort {* with @ident := Induction for @ident Sort sort} where each `ident'ᵢ` is a different mutually defined function name (the names must be in the same order as when they were defined). This @@ -229,7 +242,7 @@ definition written by the user. simpl; auto with arith. Qed. - We can use directly the functional induction (:ref:`TODO-8.5.5`) tactic instead + We can use directly the functional induction (:tacn:`function induction`) tactic instead of the pattern/apply trick: .. coqtop:: all @@ -305,13 +318,15 @@ definition written by the user. .. coqtop:: all Check tree_size_ind2. + +.. _derive-inversion: Generation of inversion principles with ``Derive`` ``Inversion`` ----------------------------------------------------------------- The syntax of ``Derive`` ``Inversion`` follows the schema: -.. cmd:: Derive Inversion ident with forall (x : T), I t Sort sort +.. cmd:: Derive Inversion @ident with forall (x : T), I t Sort sort This command generates an inversion principle for the `inversion … using` tactic. Let `I` be an inductive predicate and `x` the variables occurring @@ -320,17 +335,17 @@ sort `sort` corresponding to the instance `∀ (x:T), I t` with the name `ident` in the global environment. When applied, it is equivalent to having inverted the instance with the tactic `inversion`. -.. cmdv:: Derive Inversion_clear ident with forall (x:T), I t Sort sort +.. cmdv:: Derive Inversion_clear @ident with forall (x:T), I t Sort sort When applied, it is equivalent to having inverted the instance with the tactic inversion replaced by the tactic `inversion_clear`. -.. cmdv:: Derive Dependent Inversion ident with forall (x:T), I t Sort sort +.. cmdv:: Derive Dependent Inversion @ident with forall (x:T), I t Sort sort When applied, it is equivalent to having inverted the instance with the tactic `dependent inversion`. -.. cmdv:: Derive Dependent Inversion_clear ident with forall(x:T), I t Sort sort +.. cmdv:: Derive Dependent Inversion_clear @ident with forall(x:T), I t Sort sort When applied, it is equivalent to having inverted the instance with the tactic `dependent inversion_clear`. diff --git a/doc/sphinx/user-extensions/syntax-extensions.rst b/doc/sphinx/user-extensions/syntax-extensions.rst index 6e6d664475..3b95a37ed3 100644 --- a/doc/sphinx/user-extensions/syntax-extensions.rst +++ b/doc/sphinx/user-extensions/syntax-extensions.rst @@ -10,12 +10,12 @@ parses and prints objects, i.e. the translations between the concrete and internal representations of terms and commands. The main commands to provide custom symbolic notations for terms are -``Notation`` and ``Infix``. They are described in section 12.1. There is also a +``Notation`` and ``Infix``. They are described in section :ref:`Notations`. There is also a variant of ``Notation`` which does not modify the parser. This provides with a form of abbreviation and it is described in Section :ref:`Abbreviations`. It is sometimes expected that the same symbolic notation has different meanings in different contexts. To achieve this form of overloading, |Coq| offers a notion -of interpretation scope. This is described in Section :ref:`scopes`. +of interpretation scope. This is described in Section :ref:`Scopes`. The main command to provide custom notations for tactics is ``Tactic Notation``. It is described in Section :ref:`TacticNotation`. @@ -24,12 +24,16 @@ It is described in Section :ref:`TacticNotation`. Set Printing Depth 50. +.. _Notations: + Notations --------- Basic notations ~~~~~~~~~~~~~~~ +.. cmd:: Notation + A *notation* is a symbolic expression denoting some term or term pattern. @@ -68,7 +72,7 @@ have to be given. .. note:: The right-hand side of a notation is interpreted at the time the notation is - given. In particular, disambiguiation of constants, implicit arguments (see + given. In particular, disambiguation of constants, implicit arguments (see Section :ref:`ImplicitArguments`), coercions (see Section :ref:`Coercions`), etc. are resolved at the time of the declaration of the notation. @@ -196,7 +200,7 @@ need to force the parsing level of y, as follows. For the sake of factorization with Coq predefined rules, simple rules have to be observed for notations starting with a symbol: e.g. rules starting with “{” or “(” should be put at level 0. The list of Coq -predefined notations can be found in Chapter 3. +predefined notations can be found in Chapter :ref:`thecoqlibrary`. .. cmd:: Print Grammar constr. @@ -343,13 +347,13 @@ inductive type or a recursive constant and a notation for it. Simultaneous definition of terms and notations ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -Thanks to reserved notations, the inductive, co-inductive, record, recursive -and corecursive definitions can benefit of customized notations. To do -this, insert a ``where`` notation clause after the definition of the -(co)inductive type or (co)recursive term (or after the definition of -each of them in case of mutual definitions). The exact syntax is given -on Figure 12.1 for inductive, co-inductive, recursive and corecursive -definitions and on Figure :ref:`record-syntax` for records. Here are examples: +Thanks to reserved notations, the inductive, co-inductive, record, recursive and +corecursive definitions can benefit of customized notations. To do this, insert +a ``where`` notation clause after the definition of the (co)inductive type or +(co)recursive term (or after the definition of each of them in case of mutual +definitions). The exact syntax is given by :token:`decl_notation` for inductive, +co-inductive, recursive and corecursive definitions and in :ref:`record-types` +for records. Here are examples: .. coqtop:: in @@ -379,23 +383,21 @@ Displaying informations about notations :opt:`Printing All` To disable other elements in addition to notations. +.. _locating-notations: + Locating notations ~~~~~~~~~~~~~~~~~~ -.. cmd:: Locate @symbol - - To know to which notations a given symbol belongs to, use the command - ``Locate symbol``, where symbol is any (composite) symbol surrounded by double - quotes. To locate a particular notation, use a string where the variables of the - notation are replaced by “_” and where possible single quotes inserted around - identifiers or tokens starting with a single quote are dropped. +To know to which notations a given symbol belongs to, use the :cmd:`Locate` +command. You can call it on any (composite) symbol surrounded by double quotes. +To locate a particular notation, use a string where the variables of the +notation are replaced by “_” and where possible single quotes inserted around +identifiers or tokens starting with a single quote are dropped. - .. coqtop:: all - - Locate "exists". - Locate "exists _ .. _ , _". +.. coqtop:: all - .. todo:: See also: Section 6.3.10. + Locate "exists". + Locate "exists _ .. _ , _". Notations and binders ~~~~~~~~~~~~~~~~~~~~~ @@ -433,8 +435,7 @@ Binders bound in the notation and parsed as patterns In the same way as patterns can be used as binders, as in :g:`fun '(x,y) => x+y` or :g:`fun '(existT _ x _) => x`, notations can be -defined so that any pattern (in the sense of the entry :n:`@pattern` of -Figure :ref:`term-syntax-aux`) can be used in place of the +defined so that any :n:`@pattern` can be used in place of the binder. Here is an example: .. coqtop:: in reset @@ -473,7 +474,7 @@ variable. Here is an example showing the difference: The default level for a ``pattern`` is 0. One can use a different level by using ``pattern at level`` :math:`n` where the scale is the same as the one for -terms (Figure :ref:`init-notations`). +terms (see :ref:`init-notations`). Binders bound in the notation and parsed as terms +++++++++++++++++++++++++++++++++++++++++++++++++ @@ -489,7 +490,7 @@ the following: This is so because the grammar also contains rules starting with :g:`{}` and followed by a term, such as the rule for the notation :g:`{ A } + { B }` for the -constant :g:`sumbool` (see Section :ref:`sumbool`). +constant :g:`sumbool` (see Section :ref:`specification`). Then, in the rule, ``x ident`` is replaced by ``x at level 99 as ident`` meaning that ``x`` is parsed as a term at level 99 (as done in the notation for @@ -689,8 +690,7 @@ side. E.g.: Summary ~~~~~~~ -Syntax of notations -~~~~~~~~~~~~~~~~~~~ +**Syntax of notations** The different syntactic variants of the command Notation are given on the following figure. The optional :token:`scope` is described in the Section 12.2. @@ -743,8 +743,7 @@ following figure. The optional :token:`scope` is described in the Section 12.2. given to some notation, say ``"{ y } & { z }"`` in fact applies to the underlying ``"{ x }"``\-free rule which is ``"y & z"``). -Persistence of notations -~~~~~~~~~~~~~~~~~~~~~~~~ +**Persistence of notations** Notations do not survive the end of sections. @@ -753,6 +752,8 @@ Notations do not survive the end of sections. Notations survive modules unless the command ``Local Notation`` is used instead of ``Notation``. +.. _Scopes: + Interpretation scopes ---------------------- @@ -827,6 +828,8 @@ lonely notations. These scopes, in opening order, are ``core_scope``, These variants survive sections. They behave as if Global were absent when not inside a section. +.. _LocalInterpretationRulesForNotations: + Local interpretation rules for notations ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -857,6 +860,7 @@ Binding arguments of a constant to an interpretation scope +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ .. cmd:: Arguments @qualid {+ @name%@scope} + :name: Arguments (scopes) It is possible to set in advance that some arguments of a given constant have to be interpreted in a given scope. The command is @@ -895,7 +899,7 @@ Binding arguments of a constant to an interpretation scope .. cmdv:: Arguments @qualid {+ @name%scope} : extra scopes Defines extra argument scopes, to be used in case of coercion to Funclass - (see Chapter :ref:`Coercions-full`) or with a computed type. + (see Chapter :ref:`implicitcoercions`) or with a computed type. .. cmdv:: Global Arguments @qualid {+ @name%@scope} @@ -912,9 +916,8 @@ Binding arguments of a constant to an interpretation scope .. seealso:: - :cmd:`About @qualid` - The command to show the scopes bound to the arguments of a - function is described in Section 2. + The command :cmd:`About` can be used to show the scopes bound to the + arguments of a function. .. note:: @@ -955,7 +958,7 @@ Binding types of arguments to an interpretation scope type :g:`t` in :g:`f t a` is not recognized as an argument to be interpreted in scope ``scope``. - More generally, any coercion :n:`@class` (see Chapter :ref:`Coercions-full`) + More generally, any coercion :n:`@class` (see Chapter :ref:`implicitcoercions`) can be bound to an interpretation scope. The command to do it is :n:`Bind Scope @scope with @class` @@ -1125,6 +1128,8 @@ Displaying informations about scopes class of all the existing interpretation scopes. It also displays the lonely notations. +.. _Abbreviations: + Abbreviations -------------- @@ -1187,6 +1192,8 @@ Abbreviations denoted expression is performed at definition time. Type-checking is done only at the time of use of the abbreviation. +.. _TacticNotation: + Tactic Notations ----------------- @@ -1194,7 +1201,7 @@ Tactic notations allow to customize the syntax of the tactics of the tactic language. Tactic notations obey the following syntax: .. productionlist:: coq - tacn : [Local] Tactic Notation [`tactic_level`] [`prod_item` … `prod_item`] := `tactic`. + tacn : Tactic Notation [`tactic_level`] [`prod_item` … `prod_item`] := `tactic`. prod_item : `string` | `tactic_argument_type`(`ident`) tactic_level : (at level `natural`) tactic_argument_type : ident | simple_intropattern | reference @@ -1205,7 +1212,7 @@ tactic language. Tactic notations obey the following syntax: : | tactic | tactic0 | tactic1 | tactic2 | tactic3 : | tactic4 | tactic5 -.. cmd:: {? Local} Tactic Notation {? (at level @level)} {+ @prod_item} := @tactic. +.. cmd:: Tactic Notation {? (at level @level)} {+ @prod_item} := @tactic. A tactic notation extends the parser and pretty-printer of tactics with a new rule made of the list of production items. It then evaluates into the |