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Diffstat (limited to 'doc/sphinx')
| -rw-r--r-- | doc/sphinx/addendum/canonical-structures.rst | 2 | ||||
| -rw-r--r-- | doc/sphinx/changes.rst | 4892 | ||||
| -rw-r--r-- | doc/sphinx/credits.rst | 1884 | ||||
| -rw-r--r-- | doc/sphinx/history.rst | 1449 | ||||
| -rw-r--r-- | doc/sphinx/index.html.rst | 3 | ||||
| -rw-r--r-- | doc/sphinx/index.latex.rst | 4 | ||||
| -rw-r--r-- | doc/sphinx/language/gallina-specification-language.rst | 12 | ||||
| -rw-r--r-- | doc/sphinx/practical-tools/utilities.rst | 110 | ||||
| -rw-r--r-- | doc/sphinx/proof-engine/tactics.rst | 2 | ||||
| -rw-r--r-- | doc/sphinx/proof-engine/vernacular-commands.rst | 14 | ||||
| -rw-r--r-- | doc/sphinx/user-extensions/syntax-extensions.rst | 46 |
11 files changed, 6498 insertions, 1920 deletions
diff --git a/doc/sphinx/addendum/canonical-structures.rst b/doc/sphinx/addendum/canonical-structures.rst index a9d894cab5..dd21ea09bd 100644 --- a/doc/sphinx/addendum/canonical-structures.rst +++ b/doc/sphinx/addendum/canonical-structures.rst @@ -92,7 +92,7 @@ and use the ``==`` notation on terms of this type. Derived Canonical Structures ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -We know how to use ``== `` on base types, like ``nat``, ``bool``, ``Z``. Here we show +We know how to use ``==`` on base types, like ``nat``, ``bool``, ``Z``. Here we show how to deal with type constructors, i.e. how to make the following example work: diff --git a/doc/sphinx/changes.rst b/doc/sphinx/changes.rst new file mode 100644 index 0000000000..57b9e45342 --- /dev/null +++ b/doc/sphinx/changes.rst @@ -0,0 +1,4892 @@ +-------------- +Recent changes +-------------- + +Version 8.9 +----------- + +Summary of changes +~~~~~~~~~~~~~~~~~~ + +|Coq| version 8.9 contains the result of refinements and stabilization +of features and deprecations or removals of deprecated features, +cleanups of the internals of the system and API along with a few new +features. This release includes many user-visible changes, including +deprecations that are documented in ``CHANGES.md`` and new features that +are documented in the reference manual. Here are the most important +changes: + +- Kernel: mutually recursive records are now supported, by Pierre-Marie + Pédrot. + +- Notations: + + - Support for autonomous grammars of terms called “custom entries”, by + Hugo Herbelin (see Section :ref:`custom-entries` of the reference + manual). + + - Deprecated notations of the standard library will be removed in the + next version of |Coq|, see the ``CHANGES.md`` file for a script to + ease porting, by Jason Gross and Jean-Christophe Léchenet. + + - Added the :cmd:`Numeral Notation` command for registering decimal + numeral notations for custom types, by Daniel de Rauglaudre, Pierre + Letouzey and Jason Gross. + +- Tactics: Introduction tactics :tacn:`intro`/:tacn:`intros` on a goal that is an + existential variable now force a refinement of the goal into a + dependent product rather than failing, by Hugo Herbelin. + +- Decision procedures: deprecation of tactic ``romega`` in favor of + :tacn:`lia` and removal of ``fourier``, replaced by :tacn:`lra` which + subsumes it, by Frédéric Besson, Maxime Dénès, Vincent Laporte and + Laurent Théry. + +- Proof language: focusing bracket ``{`` now supports named + :ref:`goals <curly-braces>`, e.g. ``[x]:{`` will focus + on a goal (existential variable) named ``x``, by Théo Zimmermann. + +- SSReflect: the implementation of delayed clear was simplified by + Enrico Tassi: the variables are always renamed using inaccessible + names when the clear switch is processed and finally cleared at the + end of the intro pattern. In addition to that, the use-and-discard flag + ``{}`` typical of rewrite rules can now be also applied to views, + e.g. ``=> {}/v`` applies ``v`` and then clears ``v``. See Section + :ref:`introduction_ssr`. + +- Vernacular: + + - Experimental support for :ref:`attributes <gallina-attributes>` on + commands, by Vincent Laporte, as in ``#[local] Lemma foo : bar.`` + Tactics and tactic notations now support the ``deprecated`` + attribute. + + - Removed deprecated commands ``Arguments Scope`` and ``Implicit + Arguments`` in favor of :cmd:`Arguments`, with the help of Jasper + Hugunin. + + - New flag :flag:`Uniform Inductive Parameters` by Jasper Hugunin to + avoid repeating uniform parameters in constructor declarations. + + - New commands :cmd:`Hint Variables` and :cmd:`Hint Constants`, by + Matthieu Sozeau, for controlling the opacity status of variables and + constants in hint databases. It is recommended to always use these + commands after creating a hint databse with :cmd:`Create HintDb`. + + - Multiple sections with the same name are now allowed, by Jasper + Hugunin. + +- Library: additions and changes in the ``VectorDef``, ``Ascii``, and + ``String`` libraries. Syntax notations are now available only when using + ``Import`` of libraries and not merely ``Require``, by various + contributors (source of incompatibility, see ``CHANGES.md`` for details). + +- Toplevels: ``coqtop`` and ``coqide`` can now display diffs between proof + steps in color, using the :opt:`Diffs` option, by Jim Fehrle. + +- Documentation: we integrated a large number of fixes to the new Sphinx + documentation by various contributors, coordinated by Clément + Pit-Claudel and Théo Zimmermann. + +- Tools: removed the ``gallina`` utility and the homebrewed ``Emacs`` mode. + +- Packaging: as in |Coq| 8.8.2, the Windows installer now includes many + more external packages that can be individually selected for + installation, by Michael Soegtrop. + +Version 8.9 also comes with a bunch of smaller-scale changes and +improvements regarding the different components of the system. Most +important ones are documented in the ``CHANGES.md`` file. + +On the implementation side, the ``dev/doc/changes.md`` file documents +the numerous changes to the implementation and improvements of +interfaces. The file provides guidelines on porting a plugin to the new +version and a plugin development tutorial kept in sync with Coq was +introduced by Yves Bertot http://github.com/ybertot/plugin_tutorials. +The new ``dev/doc/critical-bugs`` file documents the known critical bugs +of |Coq| and affected releases. + +The efficiency of the whole system has seen improvements thanks to +contributions from Gaëtan Gilbert, Pierre-Marie Pédrot, and Maxime Dénès. + +Maxime Dénès, Emilio Jesús Gallego Arias, Gaëtan Gilbert, Michael +Soegtrop, Théo Zimmermann worked on maintaining and improving the +continuous integration system. + +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 54 contributors for this version are Léo Andrès, Rin Arakaki, +Benjamin Barenblat, Langston Barrett, Siddharth Bhat, Martin Bodin, +Simon Boulier, Timothy Bourke, Joachim Breitner, Tej Chajed, Arthur +Charguéraud, Pierre Courtieu, Maxime Dénès, Andres Erbsen, Jim Fehrle, +Julien Forest, Emilio Jesus Gallego Arias, Gaëtan Gilbert, Matěj +Grabovský, Jason Gross, Samuel Gruetter, Armaël Guéneau, Hugo Herbelin, +Jasper Hugunin, Ralf Jung, Sam Pablo Kuper, Ambroise Lafont, Leonidas +Lampropoulos, Vincent Laporte, Peter LeFanu Lumsdaine, Pierre Letouzey, +Jean-Christophe Léchenet, Nick Lewycky, Yishuai Li, Sven M. Hallberg, +Assia Mahboubi, Cyprien Mangin, Guillaume Melquiond, Perry E. Metzger, +Clément Pit-Claudel, Pierre-Marie Pédrot, Daniel R. Grayson, Kazuhiko +Sakaguchi, Michael Soegtrop, Matthieu Sozeau, Paul Steckler, Enrico +Tassi, Laurent Théry, Anton Trunov, whitequark, Théo Winterhalter, +Zeimer, Beta Ziliani, Théo Zimmermann. + +Many power users helped to improve the design of the new features via +the issue and pull request system, the |Coq| development mailing list or +the coq-club@inria.fr mailing list. It would be impossible to mention +exhaustively the names of everybody who to some extent influenced the +development. + +Version 8.9 is the fourth release of |Coq| developed on a time-based +development cycle. Its development spanned 7 months from the release of +|Coq| 8.8. The development moved to a decentralized merging process +during this cycle. Guillaume Melquiond was in charge of the release +process and is the maintainer of this release. This release is the +result of ~2,000 commits and ~500 PRs merged, closing 75+ issues. + +The |Coq| development team welcomed Vincent Laporte, a new |Coq| +engineer working with Maxime Dénès in the |Coq| consortium. + +| Paris, November 2018, +| Matthieu Sozeau for the |Coq| development team +| + +Details of changes +~~~~~~~~~~~~~~~~~~ + +Kernel + +- Mutually defined records are now supported. + +Notations + +- New support for autonomous grammars of terms, called "custom + entries" (see chapter "Syntax extensions" of the reference manual). + +- Deprecated compatibility notations will actually be removed in the + next version of Coq. Uses of these notations are generally easy to + fix thanks to the hint contained in the deprecation warnings. For + projects that require more than a handful of such fixes, there is [a + script](https://gist.github.com/JasonGross/9770653967de3679d131c59d42de6d17#file-replace-notations-py) + that will do it automatically, using the output of coqc. The script + contains documentation on its usage in a comment at the top. + +- When several notations are available for the same expression, + priority is given to latest notations defined in the scopes being + opened, in order, rather than to the latest notations defined + independently of whether they are in an opened scope or not. + +Tactics + +- Added toplevel goal selector `!` which expects a single focused goal. + Use with `Set Default Goal Selector` to force focusing before tactics + are called. + +- The undocumented "nameless" forms `fix N`, `cofix` that were + deprecated in 8.8 have been removed from Ltac's syntax; please use + `fix ident N/cofix ident` to explicitly name the (co)fixpoint + hypothesis to be introduced. + +- Introduction tactics `intro`/`intros` on a goal that is an + existential variable now force a refinement of the goal into a + dependent product rather than failing. + +- Support for `fix`/`cofix` added in Ltac `match` and `lazymatch`. + +- Ltac backtraces now include trace information about tactics + called by OCaml-defined tactics. + +- Option `Ltac Debug` now applies also to terms built using Ltac functions. + +- Deprecated the `Implicit Tactic` family of commands. + +- The default program obligation tactic uses a bounded proof search + instead of an unbounded and potentially non-terminating one now + (source of incompatibility). + +- The `simple apply` tactic now respects the `Opaque` flag when called from + Ltac (`auto` still does not respect it). + +- Tactic `constr_eq` now adds universe constraints needed for the + identity to the context (it used to ignore them). New tactic + `constr_eq_strict` checks that the required constraints already hold + without adding new ones. Preexisting tactic `constr_eq_nounivs` can + still be used if you really want to ignore universe constraints. + +- Tactics and tactic notations now understand the `deprecated` attribute. +- The `fourier` tactic has been removed. Please now use `lra` instead. You + may need to add `Require Import Lra` to your developments. For compatibility, + we now define `fourier` as a deprecated alias of `lra`. + +- The `romega` tactics have been deprecated; please use `lia` instead. + +Focusing + +- Focusing bracket `{` now supports named goal selectors, + e.g. `[x]: {` will focus on a goal (existential variable) named `x`. + As usual, unfocus with `}` once the sub-goal is fully solved. + +Specification language + +- A fix to unification (which was sensitive to the ascii name of + variables) may occasionally change type inference in incompatible + ways, especially regarding the inference of the return clause of `match`. + +Standard Library + +- Added `Ascii.eqb` and `String.eqb` and the `=?` notation for them, + and proved some lemmas about them. Note that this might cause + incompatibilities if you have, e.g., `string_scope` and `Z_scope` both + open with `string_scope` on top, and expect `=?` to refer to `Z.eqb`. + Solution: wrap `_ =? _` in `(_ =? _)%Z` (or whichever scope you + want). + +- Added `Ndigits.N2Bv_sized`, and proved some lemmas about it. + Deprecated `Ndigits.N2Bv_gen`. + +- The scopes `int_scope` and `uint_scope` have been renamed to + `dec_int_scope` and `dec_uint_scope`, to clash less with ssreflect + and other packages. They are still delimited by `%int` and `%uint`. + +- Syntax notations for `string`, `ascii`, `Z`, `positive`, `N`, `R`, + and `int31` are no longer available merely by `Require`ing the files + that define the inductives. You must `Import` `Coq.Strings.String.StringSyntax` + (after `Require` `Coq.Strings.String`), `Coq.Strings.Ascii.AsciiSyntax` (after + `Require` `Coq.Strings.Ascii`), `Coq.ZArith.BinIntDef`, `Coq.PArith.BinPosDef`, + `Coq.NArith.BinNatDef`, `Coq.Reals.Rdefinitions`, and + `Coq.Numbers.Cyclic.Int31.Int31`, respectively, to be able to use + these notations. Note that passing `-compat 8.8` or issuing + `Require Import Coq.Compat.Coq88` will make these notations + available. Users wishing to port their developments automatically + may download `fix.py` from + <https://gist.github.com/JasonGross/5d4558edf8f5c2c548a3d96c17820169> + and run a command like `while true; do make -Okj 2>&1 | + /path/to/fix.py; done` and get a cup of coffee. (This command must + be manually interrupted once the build finishes all the way though. + Note also that this method is not fail-proof; you may have to adjust + some scopes if you were relying on string notations not being + available even when `string_scope` was open.) + +- Numeral syntax for `nat` is no longer available without loading the + entire prelude (`Require Import Coq.Init.Prelude`). This only + impacts users running Coq without the init library (`-nois` or + `-noinit`) and also issuing `Require Import Coq.Init.Datatypes`. + +Tools + +- Coq_makefile lets one override or extend the following variables from + the command line: `COQFLAGS`, `COQCHKFLAGS`, `COQDOCFLAGS`. + `COQFLAGS` is now entirely separate from `COQLIBS`, so in custom Makefiles + `$(COQFLAGS)` should be replaced by `$(COQFLAGS) $(COQLIBS)`. + +- Removed the `gallina` utility (extracts specification from Coq vernacular files). + If you would like to maintain this tool externally, please contact us. + +- Removed the Emacs modes distributed with Coq. You are advised to + use [Proof-General](https://proofgeneral.github.io/) (and optionally + [Company-Coq](https://github.com/cpitclaudel/company-coq)) instead. + If your use case is not covered by these alternative Emacs modes, + please open an issue. We can help set up external maintenance as part + of Proof-General, or independently as part of coq-community. + +Vernacular Commands + +- Removed deprecated commands `Arguments Scope` and `Implicit Arguments` + (not the option). Use the `Arguments` command instead. +- Nested proofs may be enabled through the option `Nested Proofs Allowed`. + By default, they are disabled and produce an error. The deprecation + warning which used to occur when using nested proofs has been removed. +- Added option `Uniform Inductive Parameters` which abstracts over parameters + before typechecking constructors, allowing to write for example + `Inductive list (A : Type) := nil : list | cons : A -> list -> list.` +- New `Set Hint Variables/Constants Opaque/Transparent` commands for setting + globally the opacity flag of variables and constants in hint databases, + overwritting the opacity set of the hint database. +- Added generic syntax for "attributes", as in: + `#[local] Lemma foo : bar.` +- Added the `Numeral Notation` command for registering decimal numeral + notations for custom types +- The `Set SsrHave NoTCResolution` command no longer has special global + scope. If you want the previous behavior, use `Global Set SsrHave + NoTCResolution`. +- Multiple sections with the same name are allowed. + +Coq binaries and process model + +- Before 8.9, Coq distributed a single `coqtop` binary and a set of + dynamically loadable plugins that used to take over the main loop + for tasks such as IDE language server or parallel proof checking. + + These plugins have been turned into full-fledged binaries so each + different process has associated a particular binary now, in + particular `coqidetop` is the CoqIDE language server, and + `coq{proof,tactic,query}worker` are in charge of task-specific and + parallel proof checking. + +SSReflect + +- The implementation of delayed clear switches in intro patterns + is now simpler to explain: + + 1. The immediate effect of a clear switch like `{x}` is to rename the + variable `x` to `_x_` (i.e. a reserved identifier that cannot be mentioned + explicitly) + 2. The delayed effect of `{x}` is that `_x_` is cleared at the end of the intro + pattern + 3. A clear switch immediately before a view application like `{x}/v` is + translated to `/v{x}`. + + In particular, the third rule lets one write `{x}/v` even if `v` uses the variable `x`: + indeed the view is executed before the renaming. + +- An empty clear switch is now accepted in intro patterns before a + view application whenever the view is a variable. + One can now write `{}/v` to mean `{v}/v`. Remark that `{}/x` is very similar + to the idiom `{}e` for the rewrite tactic (the equation `e` is used for + rewriting and then discarded). + +Standard Library + +- There are now conversions between `string` and `positive`, `Z`, + `nat`, and `N` in binary, octal, and hex. + +Display diffs between proof steps + +- `coqtop` and `coqide` can now highlight the differences between proof steps + in color. This can be enabled from the command line or the + `Set Diffs "on"/"off"/"removed"` command. Please see the documentation for + details. Showing diffs in Proof General requires small changes to PG + (under discussion). + +Notations + +- Added `++` infix for `VectorDef.append`. + Note that this might cause incompatibilities if you have, e.g., `list_scope` + and `vector_scope` both open with `vector_scope` on top, and expect `++` to + refer to `app`. + Solution: wrap `_ ++ _` in `(_ ++ _)%list` (or whichever scope you want). + +Version 8.8 +----------- + +Summary of changes +~~~~~~~~~~~~~~~~~~ + +|Coq| version 8.8 contains the result of refinements and stabilization of +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, 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. + +- Proof language: tacticals for profiling, timing and checking success + or failure of tactics by Jason Gross. The focusing bracket ``{`` + supports single-numbered goal selectors, e.g. ``2:{``, by Théo + Zimmermann. + +- Vernacular: deprecation of commands and more uniform handling of the + ``Local`` flag, by Vincent Laporte and Maxime Dénès, part of a larger + attribute system overhaul. Experimental ``Show Extraction`` command by + Pierre Letouzey. Coercion now accepts ``Prop`` or ``Type`` as a source + by Arthur Charguéraud. ``Export`` modifier for options allowing to + export the option to modules that ``Import`` and not only ``Require`` + a module, by Pierre-Marie Pédrot. + +- Universes: many user-level and API level enhancements: qualified + naming and printing, variance annotations for cumulative inductive + types, more general constraints and enhancements of the minimization + heuristics, interaction with modules by Gaëtan Gilbert, Pierre-Marie + Pédrot and Matthieu Sozeau. + +- Library: Decimal Numbers library by Pierre Letouzey and various small + improvements. + +- Documentation: a large community effort resulted in the migration + of the reference manual to the Sphinx documentation tool. The result + 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. + +On the implementation side, the ``dev/doc/changes.md`` file +documents the numerous changes to the implementation and improvements of +interfaces. The file provides guidelines on porting a plugin to the new +version. + +Version 8.8 also comes with a bunch of smaller-scale changes and +improvements regarding the different components of the system. +Most important ones are documented in the ``CHANGES.md`` file. + +The efficiency of the whole system has seen improvements thanks to +contributions from Gaëtan Gilbert, Pierre-Marie Pédrot, Maxime Dénès and +Matthieu Sozeau and performance issue tracking by Jason Gross and Paul +Steckler. + +The official wiki and the bugtracker of |Coq| migrated to the GitHub +platform, thanks to the work of Pierre Letouzey and Théo +Zimmermann. Gaëtan Gilbert, Emilio Jesús Gallego Arias worked on +maintaining and improving the continuous integration system. + +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 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 +|Coq| 8.7 and was based on a public roadmap. The development process +was coordinated by Matthieu Sozeau. Maxime Dénès was in charge of the +release process. Théo Zimmermann is the maintainer of this release. + +Many power users helped to improve the design of the new features via +the bug tracker, the pull request system, the |Coq| development mailing +list or the coq-club@inria.fr mailing list. Special thanks to the users who +contributed patches and intensive brain-storming and code reviews, +starting with Jason Gross, Ralf Jung, Robbert Krebbers and Amin Timany. +It would however be impossible to mention exhaustively the names +of everybody who to some extent influenced the development. + +The |Coq| consortium, an organization directed towards users and +supporters of the system, is now running and employs Maxime Dénès. +The contacts of the Coq Consortium are Yves Bertot and Maxime Dénès. + +| Santiago de Chile, March 2018, +| Matthieu Sozeau for the |Coq| development team +| + +Details of changes in 8.8+beta1 +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Kernel + +- Support for template polymorphism for definitions was removed. May trigger + more "universe inconsistency" errors in rare occasions. +- Fixpoints are no longer allowed on non-recursive inductive types. + +Notations + +- Recursive notations with the recursive pattern repeating on the + right (e.g. "( x ; .. ; y ; z )") now supported. +- Notations with a specific level for the leftmost nonterminal, + when printing-only, are supported. +- Notations can now refer to the syntactic category of patterns (as in + "fun 'pat =>" or "match p with pat => ... end"). Two variants are + available, depending on whether a single variable is considered as a + pattern or not. +- Recursive notations now support ".." patterns with several + occurrences of the recursive term or binder, possibly mixing terms + and binders, possibly in reverse left-to-right order. +- "Locate" now working also on notations of the form "x + y" (rather + than "_ + _"). + +Specification language + +- When printing clauses of a "match", clauses with same right-hand + side are factorized and the last most factorized clause with no + variables, if it exists, is turned into a default clause. + Use "Unset Printing Allow Default Clause" do deactivate printing + of a default clause. + Use "Unset Printing Factorizable Match Patterns" to deactivate + factorization of clauses with same right-hand side. + +Tactics + +- On Linux, "native_compute" calls can be profiled using the "perf" + utility. The command "Set NativeCompute Profiling" enables + profiling, and "Set NativeCompute Profile Filename" customizes + the profile filename. +- The tactic "omega" is now aware of the bodies of context variables + such as "x := 5 : Z" (see #1362). This could be disabled via + Unset Omega UseLocalDefs. +- The tactic "romega" is also aware now of the bodies of context variables. +- The tactic "zify" resp. "omega with N" is now aware of N.pred. +- Tactic "decide equality" now able to manage constructors which + contain proofs. +- Added tactics reset ltac profile, show ltac profile (and variants) +- Added tactics restart_timer, finish_timing, and time_constr as an + experimental way of timing Ltac's evaluation phase +- Added tactic optimize_heap, analogous to the Vernacular Optimize + Heap, which performs a major garbage collection and heap compaction + in the OCaml run-time system. +- The tactics "dtauto", "dintuition", "firstorder" now handle inductive types + with let bindings in the parameters. +- The tactic ``dtauto`` now handles some inductives such as + ``@sigT A (fun _ => B)`` as non-dependent conjunctions. +- A bug fixed in ``rewrite H in *`` and ``rewrite H in * |-`` may cause a + few rare incompatibilities (it was unintendedly recursively + rewriting in the side conditions generated by H). +- Added tactics "assert_succeeds tac" and "assert_fails tac" to ensure + properties of the executation of a tactic without keeping the effect + of the execution. +- `vm_compute` now supports existential variables. +- Calls to `shelve` and `give_up` within calls to tactic `refine` now working. +- Deprecated tactic `appcontext` was removed. + +Focusing + +- Focusing bracket `{` now supports single-numbered goal selector, + e.g. `2: {` will focus on the second sub-goal. As usual, unfocus + with `}` once the sub-goal is fully solved. + The `Focus` and `Unfocus` commands are now deprecated. + +Vernacular Commands + +- Proofs ending in "Qed exporting ident, .., ident" are not supported + anymore. Constants generated during `abstract` are kept private to the + local environment. +- The deprecated Coercion Local, Open Local Scope, Notation Local syntax + was removed. Use Local as a prefix instead. +- For the Extraction Language command, "OCaml" is spelled correctly. + The older "Ocaml" is still accepted, but deprecated. +- Using “Require” inside a section is deprecated. +- An experimental command "Show Extraction" allows to extract the content + of the current ongoing proof (grant wish #4129). +- Coercion now accepts the type of its argument to be "Prop" or "Type". +- The "Export" modifier can now be used when setting and unsetting options, and + will result in performing the same change when the module corresponding the + command is imported. +- The `Axiom` command does not automatically declare axioms as instances when + their type is a class. Previous behavior can be restored using `Set + Typeclasses Axioms Are Instances`. + +Universes + +- Qualified naming of global universes now works like other namespaced + objects (e.g. constants), with a separate namespace, inside and across + module and library boundaries. Global universe names introduced in an + inductive / constant / Let declaration get qualified with the name of + the declaration. +- Universe cumulativity for inductive types is now specified as a + variance for each polymorphic universe. See the reference manual for + more information. +- Inference of universe constraints with cumulative inductive types + produces more general constraints. Unsetting new option Cumulativity + Weak Constraints produces even more general constraints (but may + produce too many universes to be practical). +- Fix #5726: Notations that start with `Type` now support universe instances + with `@{u}`. +- `with Definition` now understands universe declarations + (like `@{u| Set < u}`). + +Tools + +- Coq can now be run with the option -mangle-names to change the auto-generated + name scheme. This is intended to function as a linter for developments that + want to be robust to changes in auto-generated names. This feature is experimental, + and may change or disappear without warning. +- GeoProof support was removed. + +Checker + +- The checker now accepts filenames in addition to logical paths. + +CoqIDE + +- Find and Replace All report the number of occurrences found; Find indicates + when it wraps. + +coqdep + +- Learned to read -I, -Q, -R and filenames from _CoqProject files. + This is used by coq_makefile when generating dependencies for .v + files (but not other files). + +Documentation + +- The Coq FAQ, formerly located at https://coq.inria.fr/faq, has been + moved to the GitHub wiki section of this repository; the main entry + page is https://github.com/coq/coq/wiki/The-Coq-FAQ. +- Documentation: a large community effort resulted in the migration + of the reference manual to the Sphinx documentation tool. The result + is partially integrated in this version. + +Standard Library + +- New libraries Coq.Init.Decimal, Coq.Numbers.DecimalFacts, + Coq.Numbers.DecimalNat, Coq.Numbers.DecimalPos, + Coq.Numbers.DecimalN, Coq.Numbers.DecimalZ, + Coq.Numbers.DecimalString providing a type of decimal numbers, some + facts about them, and conversions between decimal numbers and nat, + positive, N, Z, and string. +- Added [Coq.Strings.String.concat] to concatenate a list of strings + inserting a separator between each item +- Notation `'` for Zpos in QArith was removed. + +- Some deprecated aliases are now emitting warnings when used. + +Compatibility support + +- Support for compatibility with versions before 8.6 was dropped. + +Options + +- The following deprecated options have been removed: + + + `Refolding Reduction` + + `Standard Proposition Elimination` + + `Dependent Propositions Elimination` + + `Discriminate Introduction` + + `Shrink Abstract` + + `Tactic Pattern Unification` + + `Intuition Iff Unfolding` + + `Injection L2R Pattern Order` + + `Record Elimination Schemes` + + `Match Strict` + + `Tactic Compat Context` + + `Typeclasses Legacy Resolution` + + `Typeclasses Module Eta` + + `Typeclass Resolution After Apply` + +Details of changes in 8.8.0 +~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Tools + +- Asynchronous proof delegation policy was fixed. Since version 8.7 + Coq was ignoring previous runs and the `-async-proofs-delegation-threshold` + option did not have the expected behavior. + +Tactic language + +- The undocumented "nameless" forms `fix N`, `cofix` have been + deprecated; please use `fix ident N /cofix ident` to explicitely + name the (co)fixpoint hypothesis to be introduced. + +Documentation + +- The reference manual is now fully ported to Sphinx. + +Other small deprecations and bug fixes. + +Details of changes in 8.8.1 +~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Kernel + +- Fix a critical bug with cofixpoints and `vm_compute`/`native_compute` (#7333). +- Fix a critical bug with modules and algebraic universes (#7695) +- Fix a critical bug with inlining of polymorphic constants (#7615). +- Fix a critical bug with universe polymorphism and `vm_compute` (#7723). Was + present since 8.5. + +Notations + +- Fixed unexpected collision between only-parsing and only-printing + notations (issue #7462). + +Windows installer + +- The Windows installer now includes external packages Ltac2 and Equations + (it included the Bignums package since 8.8+beta1). + +Many other bug fixes, documentation improvements (including fixes of +regressions due to the Sphinx migration), and user message improvements +(for details, see the 8.8.1 milestone at +https://github.com/coq/coq/milestone/13?closed=1). + +Details of changes in 8.8.2 +~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Documentation + +- A PDF version of the reference manual is available once again. + +Tools + +- The coq-makefile targets `print-pretty-timed`, `print-pretty-timed-diff`, + and `print-pretty-single-time-diff` now correctly label the "before" and + "after" columns, rather than swapping them. + +Kernel + +- The kernel does not tolerate capture of global universes by + polymorphic universe binders, fixing a soundness break (triggered + only through custom plugins) + +Windows installer + +- The Windows installer now includes many more external packages that can be + individually selected for installation. + +Many other bug fixes and lots of documentation improvements (for details, +see the 8.8.2 milestone at https://github.com/coq/coq/milestone/15?closed=1). + +Version 8.7 +----------- + +Summary of changes +~~~~~~~~~~~~~~~~~~ + +|Coq| version 8.7 contains the result of refinements, stabilization of features +and cleanups of the internals of the system along with a few new features. The +main user visible changes are: + +- New tactics: variants of tactics supporting existential variables :tacn:`eassert`, + :tacn:`eenough`, etc... by Hugo Herbelin. Tactics ``extensionality in H`` and + :tacn:`inversion_sigma` by Jason Gross, ``specialize with ...`` accepting partial bindings + by Pierre Courtieu. + +- ``Cumulative Polymorphic Inductive`` types, allowing cumulativity of universes to + go through applied inductive types, by Amin Timany and Matthieu Sozeau. + +- Integration of the SSReflect plugin and its documentation in the reference + manual, by Enrico Tassi, Assia Mahboubi and Maxime Dénès. + +- The ``coq_makefile`` tool was completely redesigned to improve its maintainability + and the extensibility of generated Makefiles, and to make ``_CoqProject`` files + more palatable to IDEs by Enrico Tassi. + +|Coq| 8.7 involved a large amount of work on cleaning and speeding up the code +base, notably the work of Pierre-Marie Pédrot on making the tactic-level system +insensitive to existential variable expansion, providing a safer API to plugin +writers and making the code more robust. The ``dev/doc/changes.txt`` file +documents the numerous changes to the implementation and improvements of +interfaces. An effort to provide an official, streamlined API to plugin writers +is in progress, thanks to the work of Matej Košík. + +Version 8.7 also comes with a bunch of smaller-scale changes and improvements +regarding the different components of the system. We shall only list a few of +them. + +The efficiency of the whole system has been significantly improved thanks to +contributions from Pierre-Marie Pédrot, Maxime Dénès and Matthieu Sozeau and +performance issue tracking by Jason Gross and Paul Steckler. + +Thomas Sibut-Pinote and Hugo Herbelin added support for side effect hooks in +cbv, cbn and simpl. The side effects are provided via a plugin available at +https://github.com/herbelin/reduction-effects/. + +The BigN, BigZ, BigQ libraries are no longer part of the |Coq| standard library, +they are now provided by a separate repository https://github.com/coq/bignums, +maintained by Pierre Letouzey. + +In the Reals library, ``IZR`` has been changed to produce a compact representation +of integers and real constants are now represented using ``IZR`` (work by +Guillaume Melquiond). + +Standard library additions and improvements by Jason Gross, Pierre Letouzey and +others, documented in the ``CHANGES.md`` file. + +The mathematical proof language/declarative mode plugin was removed from the +archive. + +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/. + +Packaging tools and software development kits were prepared by Michael Soegtrop +with the help of Maxime Dénès and Enrico Tassi for Windows, and Maxime Dénès for +MacOS X. Packages are regularly built on the Travis continuous integration +server. + +The contributors for this version are Abhishek Anand, C.J. Bell, Yves Bertot, +Frédéric Besson, Tej Chajed, Pierre Courtieu, Maxime Dénès, Julien Forest, +Gaëtan Gilbert, Jason Gross, Hugo Herbelin, Emilio Jesús Gallego Arias, Ralf +Jung, Matej Košík, Xavier Leroy, Pierre Letouzey, Assia Mahboubi, Cyprien +Mangin, Erik Martin-Dorel, Olivier Marty, Guillaume Melquiond, Sam Pablo Kuper, +Benjamin Pierce, Pierre-Marie Pédrot, Lars Rasmusson, Lionel Rieg, Valentin +Robert, Yann Régis-Gianas, Thomas Sibut-Pinote, Michael Soegtrop, Matthieu +Sozeau, Arnaud Spiwack, Paul Steckler, George Stelle, Pierre-Yves Strub, Enrico +Tassi, Hendrik Tews, Amin Timany, Laurent Théry, Vadim Zaliva and Théo +Zimmermann. + +The development process was coordinated by Matthieu Sozeau with the help of +Maxime Dénès, who was also in charge of the release process. Théo Zimmermann is +the maintainer of this release. + +Many power users helped to improve the design of the new features via the bug +tracker, the pull request system, the |Coq| development mailing list or the +Coq-Club mailing list. Special thanks to the users who contributed patches and +intensive brain-storming and code reviews, starting with Jason Gross, Ralf Jung, +Robbert Krebbers, Xavier Leroy, Clément Pit–Claudel and Gabriel Scherer. It +would however be impossible to mention exhaustively the names of everybody who +to some extent influenced the development. + +Version 8.7 is the second release of |Coq| developed on a time-based development +cycle. Its development spanned 9 months from the release of |Coq| 8.6 and was +based on a public road-map. It attracted many external contributions. Code +reviews and continuous integration testing were systematically used before +integration of new features, with an important focus given to compatibility and +performance issues, resulting in a hopefully more robust release than |Coq| 8.6 +while maintaining compatibility. + +|Coq| Enhancement Proposals (CEPs for short) and open pull request discussions +were used to discuss publicly the new features. + +The |Coq| consortium, an organization directed towards users and supporters of the +system, is now upcoming and will rely on Inria’s newly created Foundation. + +| Paris, August 2017, +| Matthieu Sozeau and the |Coq| development team +| + +Potential compatibility issues +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +- Extra superfluous names in introduction patterns may now raise an + error rather than a warning when the superfluous name is already in + use. The easy fix is to remove the superfluous name. + +Details of changes in 8.7+beta1 +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Tactics + +- New tactic "extensionality in H" which applies (possibly dependent) + functional extensionality in H supposed to be a quantified equality + until giving a bare equality. + +- New tactic ``inversion_sigma`` which turns equalities of dependent + pairs (e.g., ``existT P x p = existT P y q``, frequently left over by + ``inversion`` on a dependent type family) into pairs of equalities + (e.g., a hypothesis ``H : x = y`` and a hypothesis of type ``rew H in p = q``); + these hypotheses can subsequently be simplified using + ``subst``, without ever invoking any kind of axiom asserting + uniqueness of identity proofs. If you want to explicitly specify the + hypothesis to be inverted, or name the generated hypotheses, you can + invoke ``induction H as [H1 H2] using eq_sigT_rect``. The tactic also + works for ``sig``, ``sigT2``, and ``sig2``, and there are similar + ``eq_sig*_rect`` induction lemmas. + +- Tactic "specialize with ..." now accepts any partial bindings. + Missing bindings are either solved by unification or left quantified + in the hypothesis. + +- New representation of terms that statically ensure stability by + evar-expansion. This has several consequences. + + * In terms of performance, this adds a cost to every term destructuration, + but at the same time most eager evar normalizations were removed, which + couterbalances this drawback and even sometimes outperforms the old + implementation. For instance, many operations that would require O(n) + normalization of the term are now O(1) in tactics. YMMV. + + * This triggers small changes in unification, which was not evar-insensitive. + Most notably, the new implementation recognizes Miller patterns that were + missed before because of a missing normalization step. Hopefully this should + be fairly uncommon. + +- Tactic "auto with real" can now discharge comparisons of literals. + +- The types of variables in patterns of "match" are now + beta-iota-reduced after type-checking. This has an impact on the + type of the variables that the tactic "refine" introduces in the + context, producing types a priori closer to the expectations. + +- In "Tactic Notation" or "TACTIC EXTEND", entry "constr_with_bindings" + now uses type classes and rejects terms with unresolved holes, like + entry "constr" does. To get the former behavior use + "open_constr_with_bindings" (possible source of incompatibility). + +- New e-variants eassert, eenough, epose proof, eset, eremember, epose + which behave like the corresponding variants with no "e" but turn + unresolved implicit arguments into existential variables, on the + shelf, rather than failing. + +- Tactic injection has become more powerful (closes bug #4890) and its + documentation has been updated. + +- New variants of the `first` and `solve` tacticals that do not rely + on parsing rules, meant to define tactic notations. + +- Added support for side effects hooks in `cbv`, `cbn` and `simpl`. + The side effects are provided via a plugin: + https://github.com/herbelin/reduction-effects/ + +- It is now possible to take hint database names as parameters in a + Ltac definition or a Tactic Notation. + +- New option `Set Ltac Batch Debug` on top of `Set Ltac Debug` for + non-interactive Ltac debug output. + +Gallina + +- Now supporting all kinds of binders, including 'pat, in syntax of record fields. + +Vernacular Commands + +- Goals context can be printed in a more compact way when `Set + Printing Compact Contexts` is activated. +- Unfocused goals can be printed with the `Set Printing Unfocused` + option. +- `Print` now shows the types of let-bindings. +- The compatibility options for printing primitive projections + (`Set Printing Primitive Projection Parameters` and + `Set Printing Primitive Projection Compatibility`) are now off by default. +- Possibility to unset the printing of notations in a more fine grained + fashion than `Unset Printing Notations` is provided without any + user-syntax. The goal is that someone creates a plugin to experiment + such a user-syntax, to be later integrated in Coq when stabilized. +- `About` now tells if a reference is a coercion. +- The deprecated `Save` vernacular and its form `Save Theorem id` to + close proofs have been removed from the syntax. Please use `Qed`. +- `Search` now sorts results by relevance (the relevance metric is a + weighted sum of number of distinct symbols and size of the term). + +Standard Library + +- New file PropExtensionality.v to explicitly work in the axiomatic + context of propositional extensionality. +- New file SetoidChoice.v axiomatically providing choice over setoids, + and, consequently, choice of representatives in equivalence classes. + Various proof-theoretic characterizations of choice over setoids in + file ChoiceFacts.v. +- New lemmas about iff and about orders on positive and Z. +- New lemmas on powerRZ. +- Strengthened statement of JMeq_eq_dep (closes bug #4912). +- The BigN, BigZ, BigZ libraries are no longer part of the Coq standard + library, they are now provided by a separate repository + https://github.com/coq/bignums + The split has been done just after the Int31 library. + +- IZR (Reals) has been changed to produce a compact representation of + integers. As a consequence, IZR is no longer convertible to INR and + lemmas such as INR_IZR_INZ should be used instead. +- Real constants are now represented using IZR rather than R0 and R1; + this might cause rewriting rules to fail to apply to constants. +- Added new notation {x & P} for sigT (without a type for x) + +Plugins + +- The Ssreflect plugin is now distributed with Coq. Its documentation has + been integrated as a chapter of the reference manual. This chapter is + work in progress so feedback is welcome. +- The mathematical proof language (also known as declarative mode) was removed. +- A new command Extraction TestCompile has been introduced, not meant + for the general user but instead for Coq's test-suite. +- The extraction plugin is no longer loaded by default. It must be + explicitly loaded with [Require Extraction], which is backwards + compatible. +- The functional induction plugin (which provides the [Function] + vernacular) is no longer loaded by default. It must be explicitly + loaded with [Require FunInd], which is backwards compatible. + + +Dependencies + +- Support for camlp4 has been removed. + +Tools + +- coq_makefile was completely redesigned to improve its maintainability and + the extensibility of generated Makefiles, and to make _CoqProject files + more palatable to IDEs. Overview: + + * _CoqProject files contain only Coq specific data (i.e. the list of + files, -R options, ...) + * coq_makefile translates _CoqProject to Makefile.conf and copies in the + desired location a standard Makefile (that reads Makefile.conf) + * Makefile extensions can be implemented in a Makefile.local file (read + by the main Makefile) by installing a hook in the extension points + provided by the standard Makefile + + The current version contains code for retro compatibility that prints + warnings when a deprecated feature is used. Please upgrade your _CoqProject + accordingly. + + * Additionally, coq_makefile-made Makefiles now support experimental timing + targets `pretty-timed`, `pretty-timed-before`, `pretty-timed-after`, + `print-pretty-timed-diff`, `print-pretty-single-time-diff`, + `all.timing.diff`, and the variable `TIMING=1` (or `TIMING=before` or + `TIMING=after`); see the documentation for more details. + +Build Infrastructure + +- Note that 'make world' does not build the bytecode binaries anymore. + For that, you can use 'make byte' (and 'make install-byte' afterwards). + Warning: native and byte compilations should *not* be mixed in the same + instance of 'make -j', otherwise both ocamlc and ocamlopt might race for + access to the same .cmi files. In short, use "make -j && make -j byte" + instead of "make -j world byte". + +Universes + +- Cumulative inductive types. see prefixes "Cumulative", "NonCumulative" + for inductive definitions and the option "Set Polymorphic Inductive Cumulativity" + in the reference manual. +- New syntax `foo@{_}` to instantiate a polymorphic definition with + anonymous universes (can also be used with `Type`). + +XML Protocol and internal changes + +See dev/doc/changes.txt + +Many bugfixes including #1859, #2884, #3613, #3943, #3994, +#4250, #4709, #4720, #4824, #4844, #4911, #5026, #5233, +#5275, #5315, #5336, #5360, #5390, #5414, #5417, #5420, +#5439, #5449, #5475, #5476, #5482, #5501, #5507, #5520, +#5523, #5524, #5553, #5577, #5578, #5589, #5597, #5598, +#5607, #5618, #5619, #5620, #5641, #5648, #5651, #5671. + +Many bugfixes on OS X and Windows (now the test-suite passes on these +platforms too). + +Many optimizations. + +Many documentation improvements. + +Details of changes in 8.7+beta2 +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Tools + +- In CoqIDE, the "Compile Buffer" command takes account of flags in + _CoqProject or other project file. + +Improvements around some error messages. + +Many bug fixes including two important ones: + +- Bug #5730: CoqIDE becomes unresponsive on file open. +- coq_makefile: make sure compile flags for Coq and coq_makefile are in sync + (in particular, make sure the `-safe-string` option is used to compile plugins). + +Details of changes in 8.7.0 +~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +OCaml + +- Users can pass specific flags to the OCaml optimizing compiler by + -using the flambda-opts configure-time option. + + Beware that compiling Coq with a flambda-enabled compiler is + experimental and may require large amounts of RAM and CPU, see + INSTALL for more details. + +Details of changes in 8.7.1 +~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Compatibility with OCaml 4.06.0. + +Many bug fixes, documentation improvements, and user message improvements (for +details see the 8.7.1 milestone at https://github.com/coq/coq/milestone/10?closed=1). + +Details of changes in 8.7.2 +~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Fixed a critical bug in the VM handling of universes (#6677). This bug +affected all releases since 8.5. + +Improved support for building with OCaml 4.06.0 and external num package. + +Many other bug fixes, documentation improvements, and user +message improvements (for details, see the 8.7.2 milestone at +https://github.com/coq/coq/milestone/11?closed=1). + +Version 8.6 +----------- + +Summary of changes +~~~~~~~~~~~~~~~~~~ + +Coq version 8.6 contains the result of refinements, stabilization of +8.5’s features and cleanups of the internals of the system. Over the +year of (now time-based) development, about 450 bugs were resolved and +over 100 contributions integrated. The main user visible changes are: + +- A new, faster state-of-the-art universe constraint checker, by + Jacques-Henri Jourdan. + +- In |CoqIDE| and other asynchronous interfaces, more fine-grained + asynchronous processing and error reporting by Enrico Tassi, making + |Coq| capable of recovering from errors and continue processing the + document. + +- More access to the proof engine features from Ltac: goal management + primitives, range selectors and a :tacn:`typeclasses eauto` engine handling + multiple goals and multiple successes, by Cyprien Mangin, Matthieu + Sozeau and Arnaud Spiwack. + +- Tactic behavior uniformization and specification, generalization of + intro-patterns by Hugo Herbelin and others. + +- A brand new warning system allowing to control warnings, turn them + into errors or ignore them selectively by Maxime Dénès, Guillaume + Melquiond, Pierre-Marie Pédrot and others. + +- Irrefutable patterns in abstractions, by Daniel de Rauglaudre. + +- The ssreflect subterm selection algorithm by Georges Gonthier and + Enrico Tassi is now accessible to tactic writers through the + ssrmatching plugin. + +- Integration of LtacProf, a profiler for Ltac by Jason Gross, Paul + Steckler, Enrico Tassi and Tobias Tebbi. + +Coq 8.6 also comes with a bunch of smaller-scale changes and +improvements regarding the different components of the system. We shall +only list a few of them. + +The iota reduction flag is now a shorthand for match, fix and cofix +flags controlling the corresponding reduction rules (by Hugo Herbelin +and Maxime Dénès). + +Maxime Dénès maintained the native compilation machinery. + +Pierre-Marie Pédrot separated the Ltac code from general purpose +tactics, and generalized and rationalized the handling of generic +arguments, allowing to create new versions of Ltac more easily in the +future. + +In patterns and terms, @, abbreviations and notations are now +interpreted the same way, by Hugo Herbelin. + +Name handling for universes has been improved by Pierre-Marie Pédrot and +Matthieu Sozeau. The minimization algorithm has been improved by +Matthieu Sozeau. + +The unifier has been improved by Hugo Herbelin and Matthieu Sozeau, +fixing some incompatibilities introduced in |Coq| 8.5. Unification +constraints can now be left floating around and be seen by the user +thanks to a new option. The Keyed Unification mode has been improved by +Matthieu Sozeau. + +The typeclass resolution engine and associated proof-search tactic have +been reimplemented on top of the proof-engine monad, providing better +integration in tactics, and new options have been introduced to control +it, by Matthieu Sozeau with help from Théo Zimmermann. + +The efficiency of the whole system has been significantly improved +thanks to contributions from Pierre-Marie Pédrot, Maxime Dénès and +Matthieu Sozeau and performance issue tracking by Jason Gross and Paul +Steckler. + +Standard library improvements by Jason Gross, Sébastien Hinderer, Pierre +Letouzey and others. + +Emilio Jesús Gallego Arias contributed many cleanups and refactorings of +the pretty-printing and user interface communication components. + +Frédéric Besson maintained the micromega tactic. + +The OPAM repository for |Coq| packages has been maintained by Guillaume +Claret, Guillaume Melquiond, Matthieu Sozeau, Enrico Tassi and others. A +list of packages is now available at https://coq.inria.fr/opam/www/. + +Packaging tools and software development kits were prepared by Michael +Soegtrop with the help of Maxime Dénès and Enrico Tassi for Windows, and +Maxime Dénès and Matthieu Sozeau for MacOS X. Packages are now regularly +built on the continuous integration server. |Coq| now comes with a META +file usable with ocamlfind, contributed by Emilio Jesús Gallego Arias, +Gregory Malecha, and Matthieu Sozeau. + +Matej Košík maintained and greatly improved the continuous integration +setup and the testing of |Coq| contributions. He also contributed many API +improvements and code cleanups throughout the system. + +The contributors for this version are Bruno Barras, C.J. Bell, Yves +Bertot, Frédéric Besson, Pierre Boutillier, Tej Chajed, Guillaume +Claret, Xavier Clerc, Pierre Corbineau, Pierre Courtieu, Maxime Dénès, +Ricky Elrod, Emilio Jesús Gallego Arias, Jason Gross, Hugo Herbelin, +Sébastien Hinderer, Jacques-Henri Jourdan, Matej Košík, Xavier Leroy, +Pierre Letouzey, Gregory Malecha, Cyprien Mangin, Erik Martin-Dorel, +Guillaume Melquiond, Clément Pit–Claudel, Pierre-Marie Pédrot, Daniel de +Rauglaudre, Lionel Rieg, Gabriel Scherer, Thomas Sibut-Pinote, Matthieu +Sozeau, Arnaud Spiwack, Paul Steckler, Enrico Tassi, Laurent Théry, +Nickolai Zeldovich and Théo Zimmermann. The development process was +coordinated by Hugo Herbelin and Matthieu Sozeau with the help of Maxime +Dénès, who was also in charge of the release process. + +Many power users helped to improve the design of the new features via +the bug tracker, the pull request system, the |Coq| development mailing +list or the Coq-Club mailing list. Special thanks to the users who +contributed patches and intensive brain-storming and code reviews, +starting with Cyril Cohen, Jason Gross, Robbert Krebbers, Jonathan +Leivent, Xavier Leroy, Gregory Malecha, Clément Pit–Claudel, Gabriel +Scherer and Beta Ziliani. It would however be impossible to mention +exhaustively the names of everybody who to some extent influenced the +development. + +Version 8.6 is the first release of |Coq| developed on a time-based +development cycle. Its development spanned 10 months from the release of +Coq 8.5 and was based on a public roadmap. To date, it contains more +external contributions than any previous |Coq| system. Code reviews were +systematically done before integration of new features, with an +important focus given to compatibility and performance issues, resulting +in a hopefully more robust release than |Coq| 8.5. + +Coq Enhancement Proposals (CEPs for short) were introduced by Enrico +Tassi to provide more visibility and a discussion period on new +features, they are publicly available https://github.com/coq/ceps. + +Started during this period, an effort is led by Yves Bertot and Maxime +Dénès to put together a |Coq| consortium. + +| Paris, November 2016, +| Matthieu Sozeau and the |Coq| development team +| + +Potential sources of incompatibilities +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +- Symptom: An obligation generated by Program or an abstracted subproof + has different arguments. + + Cause: Set Shrink Abstract and Set Shrink Obligations are on by default + and the subproof does not use the argument. + + Remedy: + + + Adapt the script. + + Write an explicit lemma to prove the obligation/subproof and use it + instead (compatible with 8.4). + + Unset the option for the program/proof the obligation/subproof originates + from. + +- Symptom: In a goal, order of hypotheses, or absence of an equality of + the form "x = t" or "t = x", or no unfolding of a local definition. + + Cause: This might be connected to a number of fixes in the tactic + "subst". The former behavior can be reactivated by issuing "Unset + Regular Subst Tactic". + +Details of changes in 8.6beta1 +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Kernel + +- A new, faster state-of-the-art universe constraint checker. + +Specification language + +- Giving implicit arguments explicitly to a constant with multiple + choices of implicit arguments does not break any more insertion of + further maximal implicit arguments. +- Ability to put any pattern in binders, prefixed by quote, e.g. + "fun '(a,b) => ...", "λ '(a,(b,c)), ...", "Definition foo '(x,y) := ...". + It expands into a "let 'pattern := ..." + +Tactics + +- Flag "Bracketing Last Introduction Pattern" is now on by default. +- Flag "Regular Subst Tactic" is now on by default: it respects the + initial order of hypothesis, it contracts cycles, it unfolds no + local definitions (common source of incompatibilities, fixable by + "Unset Regular Subst Tactic"). +- New flag "Refolding Reduction", now disabled by default, which turns + on refolding of constants/fixpoints (as in cbn) during the reductions + done during type inference and tactic retyping. Can be extremely + expensive. When set off, this recovers the 8.4 behaviour of unification + and type inference. Potential source of incompatibility with 8.5 developments + (the option is set on in Compat/Coq85.v). +- New flag "Shrink Abstract" that minimalizes proofs generated by the abstract + tactical w.r.t. variables appearing in the body of the proof. + On by default and deprecated. Minor source of incompatibility + for code relying on the precise arguments of abstracted proofs. +- Serious bugs are fixed in tactic "double induction" (source of + incompatibilities as soon as the inductive types have dependencies in + the type of their constructors; "double induction" remains however + deprecated). +- In introduction patterns of the form (pat1,...,patn), n should match + the exact number of hypotheses introduced (except for local definitions + for which pattern can be omitted, as in regular pattern-matching). +- Tactic scopes in Ltac like constr: and ltac: now require parentheses around + their argument. +- Every generic argument type declares a tactic scope of the form "name:(...)" + where name is the name of the argument. This generalizes the constr: and ltac: + instances. +- When in strict mode (i.e. in a Ltac definition), if the "intro" tactic is + given a free identifier, it is not bound in subsequent tactics anymore. + In order to introduce a binding, use e.g. the "fresh" primitive instead + (potential source of incompatibilities). +- New tactics is_ind, is_const, is_proj, is_constructor for use in Ltac. +- New goal selectors. Sets of goals can be selected by listing integers + ranges. Example: "1,4-7,24: tac" focuses "tac" on goals 1,4,5,6,7,24. +- For uniformity with "destruct"/"induction" and for a more natural + behavior, "injection" can now work in place by activating option + "Structural Injection". In this case, hypotheses are also put in the + context in the natural left-to-right order and the hypothesis on + which injection applies is cleared. +- Tactic "contradiction" (hence "easy") now also solve goals with + hypotheses of the form "~True" or "t<>t" (possible source of + incompatibilities because of more successes in automation, but + generally a more intuitive strategy). +- Option "Injection On Proofs" was renamed "Keep Proof Equalities". When + enabled, injection and inversion do not drop equalities between objects + in Prop. Still disabled by default. +- New tactics "notypeclasses refine" and "simple notypeclasses refine" that + disallow typeclass resolution when typechecking their argument, for use + in typeclass hints. +- Integration of LtacProf, a profiler for Ltac. +- Reduction tactics now accept more fine-grained flags: iota is now a shorthand + for the new flags match, fix and cofix. +- The ssreflect subterm selection algorithm is now accessible to tactic writers + through the ssrmatching plugin. +- When used as an argument of an ltac function, "auto" without "with" + nor "using" clause now correctly uses only the core hint database by + default. + +Hints + +- Revised the syntax of [Hint Cut] to follow standard notation for regexps. +- Hint Mode now accepts "!" which means that the mode matches only if the + argument's head is not an evar (it goes under applications, casts, and + scrutinees of matches and projections). +- Hints can now take an optional user-given pattern, used only by + [typeclasses eauto] with the [Filtered Unification] option on. + +Typeclasses + +- Many new options and new engine based on the proof monad. The + [typeclasses eauto] tactic is now a multi-goal, multi-success tactic. + See reference manual for more information. It is planned to + replace auto and eauto in the following version. The 8.5 resolution + engine is still available to help solve compatibility issues. + +Program + +- The "Shrink Obligations" flag now applies to all obligations, not only + those solved by the automatic tactic. +- "Shrink Obligations" is on by default and deprecated. Minor source of + incompatibility for code relying on the precise arguments of + obligations. + +Notations + +- "Bind Scope" can once again bind "Funclass" and "Sortclass". + +General infrastructure + +- New configurable warning system which can be controlled with the vernacular + command "Set Warnings", or, under coqc/coqtop, with the flag "-w". In + particular, the default is now that warnings are printed by coqc. +- In asynchronous mode, Coq is now capable of recovering from errors and + continue processing the document. + +Tools + +- coqc accepts a -o option to specify the output file name +- coqtop accepts --print-version to print Coq and OCaml versions in + easy to parse format +- Setting [Printing Dependent Evars Line] can be unset to disable the + computation associated with printing the "dependent evars: " line in + -emacs mode +- Removed the -verbose-compat-notations flag and the corresponding Set + Verbose Compat vernacular, since these warnings can now be silenced or + turned into errors using "-w". + +XML protocol + +- message format has changed, see dev/doc/changes.txt for more details. + +Many bug fixes, minor changes and documentation improvements are not mentioned +here. + +Details of changes in 8.6 +~~~~~~~~~~~~~~~~~~~~~~~~~ + +Kernel + +- Fixed critical bug #5248 in VM long multiplication on 32-bit + architectures. Was there only since 8.6beta1, so no stable release impacted. + +Other bug fixes in universes, type class shelving,... + +Details of changes in 8.6.1 +~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +- Fix #5380: Default colors for CoqIDE are actually applied. +- Fix plugin warnings +- Document named evars (including Show ident) +- Fix Bug #5574, document function scope +- Adding a test case as requested in bug 5205. +- Fix Bug #5568, no dup notation warnings on repeated module imports +- Fix documentation of Typeclasses eauto := +- Refactor documentation of records. +- Protecting from warnings while compiling 8.6 +- Fixing an inconsistency between configure and configure.ml +- Add test-suite checks for coqchk with constraints +- Fix bug #5019 (looping zify on dependent types) +- Fix bug 5550: "typeclasses eauto with" does not work with section variables. +- Bug 5546, qualify datatype constructors when needed in Show Match +- Bug #5535, test for Show with -emacs +- Fix bug #5486, don't reverse ids in tuples +- Fixing #5522 (anomaly with free vars of pat) +- Fix bug #5526, don't check for nonlinearity in notation if printing only +- Fix bug #5255 +- Fix bug #3659: -time should understand multibyte encodings. +- FIx bug #5300: Anomaly: Uncaught exception Not_found" in "Print Assumptions". +- Fix outdated description in RefMan. +- Repairing `Set Rewriting Schemes` +- Fixing #5487 (v8.5 regression on ltac-matching expressions with evars). +- Fix description of command-line arguments for Add (Rec) LoadPath +- Fix bug #5377: @? patterns broken. +- add XML protocol doc +- Fix anomaly when doing [all:Check _.] during a proof. +- Correction of bug #4306 +- Fix #5435: [Eval native_compute in] raises anomaly. +- Instances should obey universe binders even when defined by tactics. +- Intern names bound in match patterns +- funind: Ignore missing info for current function +- Do not typecheck twice the type of opaque constants. +- show unused intro pattern warning +- [future] Be eager when "chaining" already resolved future values. +- Opaque side effects +- Fix #5132: coq_makefile generates incorrect install goal +- Run non-tactic comands without resilient_command +- Univs: fix bug #5365, generation of u+k <= v constraints +- make ``emit`` tail recursive +- Don't require printing-only notation to be productive +- Fix the way setoid_rewrite handles bindings. +- Fix for bug 5244 - set printing width ignored when given enough space +- Fix bug 4969, autoapply was not tagging shelved subgoals correctly + +Version 8.5 +----------- + +Summary of changes +~~~~~~~~~~~~~~~~~~ + +Coq version 8.5 contains the result of five specific long-term projects: + +- A new asynchronous evaluation and compilation mode by Enrico Tassi + with help from Bruno Barras and Carst Tankink. + +- Full integration of the new proof engine by Arnaud Spiwack helped by + Pierre-Marie Pédrot, + +- Addition of conversion and reduction based on native compilation by + Maxime Dénès and Benjamin Grégoire. + +- Full universe polymorphism for definitions and inductive types by + Matthieu Sozeau. + +- An implementation of primitive projections with + :math:`\eta`\-conversion bringing significant performance improvements + when using records by Matthieu Sozeau. + +The full integration of the proof engine, by Arnaud Spiwack and +Pierre-Marie Pédrot, brings to primitive tactics and the user level Ltac +language dependent subgoals, deep backtracking and multiple goal +handling, along with miscellaneous features and an improved potential +for future modifications. Dependent subgoals allow statements in a goal +to mention the proof of another. Proofs of unsolved subgoals appear as +existential variables. Primitive backtracking makes it possible to write +a tactic with several possible outcomes which are tried successively +when subsequent tactics fail. Primitives are also available to control +the backtracking behavior of tactics. Multiple goal handling paves the +way for smarter automation tactics. It is currently used for simple goal +manipulation such as goal reordering. + +The way |Coq| processes a document in batch and interactive mode has been +redesigned by Enrico Tassi with help from Bruno Barras. Opaque proofs, +the text between Proof and Qed, can be processed asynchronously, +decoupling the checking of definitions and statements from the checking +of proofs. It improves the responsiveness of interactive development, +since proofs can be processed in the background. Similarly, compilation +of a file can be split into two phases: the first one checking only +definitions and statements and the second one checking proofs. A file +resulting from the first phase – with the .vio extension – can be +already Required. All .vio files can be turned into complete .vo files +in parallel. The same infrastructure also allows terminating tactics to +be run in parallel on a set of goals via the ``par:`` goal selector. + +|CoqIDE| was modified to cope with asynchronous checking of the document. +Its source code was also made separate from that of |Coq|, so that |CoqIDE| +no longer has a special status among user interfaces, paving the way for +decoupling its release cycle from that of |Coq| in the future. + +Carst Tankink developed a |Coq| back-end for user interfaces built on +Makarius Wenzel’s Prover IDE framework (PIDE), like PIDE/jEdit (with +help from Makarius Wenzel) or PIDE/Coqoon (with help from Alexander +Faithfull and Jesper Bengtson). The development of such features was +funded by the Paral-ITP French ANR project. + +The full universe polymorphism extension was designed by Matthieu +Sozeau. It conservatively extends the universes system and core calculus +with definitions and inductive declarations parameterized by universes +and constraints. It is based on a modification of the kernel +architecture to handle constraint checking only, leaving the generation +of constraints to the refinement/type inference engine. Accordingly, +tactics are now fully universe aware, resulting in more localized error +messages in case of inconsistencies and allowing higher-level algorithms +like unification to be entirely type safe. The internal representation +of universes has been modified but this is invisible to the user. + +The underlying logic has been extended with :math:`\eta`\-conversion for +records defined with primitive projections by Matthieu Sozeau. This +additional form of :math:`\eta`\-conversion is justified using the same +principle than the previously added :math:`\eta`\-conversion for function +types, based on formulations of the Calculus of Inductive Constructions +with typed equality. Primitive projections, which do not carry the +parameters of the record and are rigid names (not defined as a +pattern matching construct), make working with nested records more +manageable in terms of time and space consumption. This extension and +universe polymorphism were carried out partly while Matthieu Sozeau was +working at the IAS in Princeton. + +The guard condition has been made compliant with extensional equality +principles such as propositional extensionality and univalence, thanks +to Maxime Dénès and Bruno Barras. To ensure compatibility with the +univalence axiom, a new flag ``-indices-matter`` has been implemented, +taking into account the universe levels of indices when computing the +levels of inductive types. This supports using |Coq| as a tool to explore +the relations between homotopy theory and type theory. + +Maxime Dénès and Benjamin Grégoire developed an implementation of +conversion test and normal form computation using the OCaml native +compiler. It complements the virtual machine conversion offering much +faster computation for expensive functions. + +Coq 8.5 also comes with a bunch of many various smaller-scale changes +and improvements regarding the different components of the system. We +shall only list a few of them. + +Pierre Boutillier developed an improved tactic for simplification of +expressions called :tacn:`cbn`. + +Maxime Dénès maintained the bytecode-based reduction machine. Pierre +Letouzey maintained the extraction mechanism. + +Pierre-Marie Pédrot has extended the syntax of terms to, experimentally, +allow holes in terms to be solved by a locally specified tactic. + +Existential variables are referred to by identifiers rather than mere +numbers, thanks to Hugo Herbelin who also improved the tactic language +here and there. + +Error messages for universe inconsistencies have been improved by +Matthieu Sozeau. Error messages for unification and type inference +failures have been improved by Hugo Herbelin, Pierre-Marie Pédrot and +Arnaud Spiwack. + +Pierre Courtieu contributed new features for using |Coq| through Proof +General and for better interactive experience (bullets, Search, etc). + +The efficiency of the whole system has been significantly improved +thanks to contributions from Pierre-Marie Pédrot. + +A distribution channel for |Coq| packages using the OPAM tool has been +initiated by Thomas Braibant and developed by Guillaume Claret, with +contributions by Enrico Tassi and feedback from Hugo Herbelin. + +Packaging tools were provided by Pierre Letouzey and Enrico Tassi +(Windows), Pierre Boutillier, Matthieu Sozeau and Maxime Dénès (MacOS +X). Maxime Dénès improved significantly the testing and benchmarking +support. + +Many power users helped to improve the design of the new features via +the bug tracker, the coq development mailing list or the Coq-Club +mailing list. Special thanks are going to the users who contributed +patches and intensive brain-storming, starting with Jason Gross, +Jonathan Leivent, Greg Malecha, Clément Pit-Claudel, Marc Lasson, Lionel +Rieg. It would however be impossible to mention with precision all names +of people who to some extent influenced the development. + +Version 8.5 is one of the most important releases of |Coq|. Its development +spanned over about 3 years and a half with about one year of +beta-testing. General maintenance during part or whole of this period +has been done by Pierre Boutillier, Pierre Courtieu, Maxime Dénès, Hugo +Herbelin, Pierre Letouzey, Guillaume Melquiond, Pierre-Marie Pédrot, +Matthieu Sozeau, Arnaud Spiwack, Enrico Tassi as well as Bruno Barras, +Yves Bertot, Frédéric Besson, Xavier Clerc, Pierre Corbineau, +Jean-Christophe Filliâtre, Julien Forest, Sébastien Hinderer, Assia +Mahboubi, Jean-Marc Notin, Yann Régis-Gianas, François Ripault, Carst +Tankink. Maxime Dénès coordinated the release process. + +| Paris, January 2015, revised December 2015, +| Hugo Herbelin, Matthieu Sozeau and the |Coq| development team +| + +Potential sources of incompatibilities +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +List of typical changes to be done to adapt files from Coq 8.4 +to Coq 8.5 when not using compatibility option ``-compat 8.4``. + +- Symptom: "The reference omega was not found in the current environment". + + Cause: "Require Omega" does not import the tactic "omega" any more + + Possible solutions: + + + use "Require Import OmegaTactic" (not compatible with 8.4) + + use "Require Import Omega" (compatible with 8.4) + + add definition "Ltac omega := Coq.omega.Omega.omega." + +- Symptom: "intuition" cannot solve a goal (not working anymore on non standard connective) + + Cause: "intuition" had an accidental non uniform behavior fixed on non standard connectives + + Possible solutions: + + + use "dintuition" instead; it is stronger than "intuition" and works + uniformly on non standard connectives, such as n-ary conjunctions or disjunctions + (not compatible with 8.4) + + do the script differently + +- Symptom: The constructor foo (in type bar) expects n arguments. + + Cause: parameters must now be given in patterns + + Possible solutions: + + + use option "Set Asymmetric Patterns" (compatible with 8.4) + + add "_" for the parameters (not compatible with 8.4) + + turn the parameters into implicit arguments (compatible with 8.4) + +- Symptom: "NPeano.Nat.foo" not existing anymore\ + + Possible solutions: + + + use "Nat.foo" instead + + Symptom: typing problems with proj1_sig or similar + + Cause: coercion from sig to sigT and similar coercions have been + removed so as to make the initial state easier to understand for + beginners + + Solution: change proj1_sig into projT1 and similarly (compatible with 8.4) + +Other detailed changes + +- options for *coq* compilation (see below for ocaml). + + + [-I foo] is now deprecated and will not add directory foo to the + coq load path (only for ocaml, see below). Just replace [-I foo] by + [-Q foo ""] in your project file and re-generate makefile. Or + perform the same operation directly in your makefile if you edit it + by hand. + + + Option -R Foo bar is the same in v8.5 than in v8.4 concerning coq + load path. + + + Option [-I foo -as bar] is unchanged but discouraged unless you + compile ocaml code. Use -Q foo bar instead. + + for more details: see section "Customization at launch + time" of the reference manual. + +- Command line options for ocaml Compilation of ocaml code (plugins) + + + [-I foo] is *not* deprecated to add foo to the ocaml load path. + + + [-I foo -as bar] adds foo to the ocaml load path *and* adds foo to + the coq load path with logical name bar (shortcut for -I foo -Q foo + bar). + + for more details: section "Customization at launch + time" of the reference manual. + +- Universe Polymorphism. + +- Refinement, unification and tactics are now aware of universes, + resulting in more localized errors. Universe inconsistencies + should no more get raised at Qed time but during the proof. + Unification *always* produces well-typed substitutions, hence + some rare cases of unifications that succeeded while producing + ill-typed terms before will now fail. + +- The [change p with c] tactic semantics changed, now typechecking + [c] at each matching occurrence [t] of the pattern [p], and + converting [t] with [c]. + +- Template polymorphic inductive types: the partial application + of a template polymorphic type (e.g. list) is not polymorphic. + An explicit parameter application (e.g [fun A => list A]) or + [apply (list _)] will result in a polymorphic instance. + +- The type inference algorithm now takes opacity of constants into + account. This may have effects on tactics using type inference + (e.g. induction). Extra "Transparent" might have to be added to + revert opacity of constants. + +Type classes. + +- When writing an ``Instance foo : Class A := {| proj := t |}`` (note the + vertical bars), support for typechecking the projections using the + type information and switching to proof mode is no longer available. + Use ``{ }`` (without the vertical bars) instead. + +Tactic abstract. + +- Auxiliary lemmas generated by the abstract tactic are removed from + the global environment and inlined in the proof term when a proof + is ended with Qed. The behavior of 8.4 can be obtained by ending + proofs with "Qed exporting" or "Qed exporting ident, .., ident". + +Details of changes in 8.5beta1 +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Logic + +- Primitive projections for records allow for a compact representation + of projections, without parameters and avoid the behavior of defined + projections that can unfold to a case expression. To turn the use of + native projections on, use [Set Primitive Projections]. Record, + Class and Structure types defined while this option is set will be + defined with primitive projections instead of the usual encoding as + a case expression. For compatibility, when p is a primitive + projection, @p can be used to refer to the projection with explicit + parameters, i.e. [@p] is definitionally equal to [λ params r. r.(p)]. + Records with primitive projections have eta-conversion, the + canonical form being [mkR pars (p1 t) ... (pn t)]. +- New universe polymorphism (see reference manual) +- New option -type-in-type to collapse the universe hierarchy (this makes the + logic inconsistent). +- The guard condition for fixpoints is now a bit stricter. Propagation + of subterm value through pattern matching is restricted according to + the return predicate. Restores compatibility of Coq's logic with the + propositional extensionality axiom. May create incompatibilities in + recursive programs heavily using dependent types. +- Trivial inductive types are no longer defined in Type but in Prop, which + leads to a non-dependent induction principle being generated in place of + the dependent one. To recover the old behavior, explicitly define your + inductive types in Set. + +Vernacular commands + +- A command "Variant" allows to define non-recursive variant types. +- The command "Record foo ..." does not generate induction principles + (foo_rect, foo_rec, foo_ind) anymore by default (feature wish + #2693). The command "Variant foo ..." does not either. A flag + "Set/Unset Nonrecursive Elimination Schemes" allows changing this. + The tactic "induction" on a "Record" or a "Variant" is now actually + doing "destruct". +- The "Open Scope" command can now be given also a delimiter (e.g. Z). +- The "Definition" command now allows the "Local" modifier, allowing + for non-importable definitions. The same goes for "Axiom" and "Parameter". +- Section-specific commands such as "Let" (resp. "Variable", "Hypothesis") used + out of a section now behave like the corresponding "Local" command, i.e. + "Local Definition" (resp. "Local Parameter", "Local Axiom"). (potential source + of rare incompatibilities). +- The "Let" command can now define local (co)fixpoints. +- Command "Search" has been renamed into "SearchHead". The command + name "Search" now behaves like former "SearchAbout". The latter name + is deprecated. +- "Search", "About", "SearchHead", "SearchRewrite" and "SearchPattern" + now search for hypothesis (of the current goal by default) first. + They now also support the goal selector prefix to specify another + goal to search: e.g. "n:Search id". This is also true for + SearchAbout although it is deprecated. +- The coq/user-contrib directory and the XDG directories are no longer + recursively added to the load path, so files from installed libraries + now need to be fully qualified for the "Require" command to find them. + The tools/update-require script can be used to convert a development. +- A new Print Strategies command allows visualizing the opacity status + of the whole engine. +- The "Locate" command now searches through all sorts of qualified namespaces of + Coq: terms, modules, tactics, etc. The old behavior of the command can be + retrieved using the "Locate Term" command. +- New "Derive" command to help writing program by derivation. +- New "Refine Instance Mode" option that allows to deactivate the generation of + obligations in incomplete typeclass instances, raising an error instead. +- "Collection" command to name sets of section hypotheses. Named collections + can be used in the syntax of "Proof using" to assert which section variables + are used in a proof. +- The "Optimize Proof" command can be placed in the middle of a proof to + force the compaction of the data structure used to represent the ongoing + proof (evar map). This may result in a lower memory footprint and speed up + the execution of the following tactics. +- "Optimize Heap" command to tell the OCaml runtime to perform a major + garbage collection step and heap compaction. +- ``Instance`` no longer treats the ``{|...|}`` syntax specially; it handles it + in the same way as other commands, e.g. "Definition". Use the ``{...}`` + syntax (no pipe symbols) to recover the old behavior. + +Specification Language + +- Slight changes in unification error messages. +- Added a syntax $(...)$ that allows putting tactics in terms (may + break user notations using "$(", fixable by inserting a space or + rewriting the notation). +- Constructors in pattern-matching patterns now respect the same rules + regarding implicit arguments as in applicative position. The old + behavior can be recovered by the command "Set Asymmetric + Patterns". As a side effect, notations for constructors explicitly + mentioning non-implicit parameters can now be used in patterns. + Considering that the pattern language is already rich enough, binding + local definitions is however now forbidden in patterns (source of + incompatibilities for local definitions that delta-reduce to a constructor). +- Type inference algorithm now granting opacity of constants. This might also + affect behavior of tactics (source of incompatibilities, solvable by + re-declaring transparent constants which were set opaque). +- Existential variables are now referred to by an identifier and the + relevant part of their instance is displayed by default. They can be + reparsed. The naming policy is yet unstable and subject to changes + in future releases. + +Tactics + +- New tactic engine allowing dependent subgoals, fully backtracking + (also known as multiple success) tactics, as well as tactics which + can consider multiple goals together. In the new tactic engine, + instantiation information of existential variables is always + propagated to tactics, removing the need to manually use the + "instantiate" tactics to mark propagation points. + + * New tactical (a+b) inserts a backtracking point. When (a+b);c fails + during the execution of c, it can backtrack and try b instead of a. + * New tactical (once a) removes all the backtracking points from a + (i.e. it selects the first success of a). + * Tactic "constructor" is now fully backtracking. In case of + incompatibilities (e.g. combinatoric explosion), the former + behavior of "constructor" can be retrieved by using instead + "[> once constructor ..]". Thanks to backtracking, undocumented + "constructor <tac>" syntax is now equivalent to + "[> once (constructor; tac) ..]". + * New "multimatch" variant of "match" tactic which backtracks to + new branches in case of a later failure. The "match" tactic is + equivalent to "once multimatch". + * New selector "all:" such that "all:tac" applies tactic "tac" to + all the focused goals, instead of just the first one as is the + default. + * A corresponding new option Set Default Goal Selector "all" makes + the tactics in scripts be applied to all the focused goal by default + * New selector "par:" such that "par:tac" applies the (terminating) + tactic "tac" to all the focused goal in parallel. The number of worker + can be selected with -async-proofs-tac-j and also limited using the + coqworkmgr utility. + * New tactics "revgoals", "cycle" and "swap" to reorder goals. + * The semantics of recursive tactics (introduced with "Ltac t := ..." + or "let rec t := ... in ...") changed slightly as t is now + applied to every goal, not each goal independently. In particular + it may be applied when no goals are left. This may cause tactics + such as "let rec t := constructor;t" to loop indefinitely. The + simple fix is to rewrite the recursive calls as follows: + "let rec t := constructor;[t..]" which recovers the earlier behavior + (source of rare incompatibilities). + * New tactic language feature "numgoals" to count number of goals. It is + accompanied by a "guard" tactic which fails if a Boolean test over + integers does not pass. + * New tactical "[> ... ]" to apply tactics to individual goals. + * New tactic "gfail" which works like "fail" except it will also + fail if every goal has been solved. + * The refine tactic is changed not to use an ad hoc typing algorithm + to generate subgoals. It also uses the dependent subgoal feature + to generate goals to materialize every existential variable which + is introduced by the refinement (source of incompatibilities). + * A tactic shelve is introduced to manage the subgoals which may be + solved by unification: shelve removes every goal it is applied to + from focus. These goals can later be called back into focus by the + Unshelve command. + * A variant shelve_unifiable only removes those goals which appear + as existential variables in other goals. To emulate the old + refine, use "refine c;shelve_unifiable". This can still cause + incompatibilities in rare occasions. + * New "give_up" tactic to skip over a goal. A proof containing + given up goals cannot be closed with "Qed", but only with "Admitted". + +- The implementation of the admit tactic has changed: no axiom is + generated for the admitted sub proof. "admit" is now an alias for + "give_up". Code relying on this specific behavior of "admit" + can be made to work by: + + * Adding an "Axiom" for each admitted subproof. + * Adding a single "Axiom proof_admitted : False." and the Ltac definition + "Ltac admit := case proof_admitted.". + +- Matching using "lazymatch" was fundamentally modified. It now behaves + like "match" (immediate execution of the matching branch) but without + the backtracking mechanism in case of failure. + +- New "tryif t then u else v" tactical which executes "u" in case of success + of "t" and "v" in case of failure. + +- New conversion tactic "native_compute": evaluates the goal (or an hypothesis) + with a call-by-value strategy, using the OCaml native compiler. Useful on + very intensive computations. + +- New "cbn" tactic, a well-behaved simpl. + +- Repeated identical calls to omega should now produce identical proof terms. + +- Tactics btauto, a reflexive Boolean tautology solver. + +- Tactic "tauto" was exceptionally able to destruct other connectives + than the binary connectives "and", "or", "prod", "sum", "iff". This + non-uniform behavior has been fixed (bug #2680) and tauto is + slightly weaker (possible source of incompatibilities). On the + opposite side, new tactic "dtauto" is able to destruct any + record-like inductive types, superseding the old version of "tauto". + +- Similarly, "intuition" has been made more uniform and, where it now + fails, "dintuition" can be used (possible source of incompatibilities). + +- New option "Unset Intuition Negation Unfolding" for deactivating automatic + unfolding of "not" in intuition. + +- Tactic notations can now be defined locally to a module (use "Local" prefix). + +- Tactic "red" now reduces head beta-iota redexes (potential source of + rare incompatibilities). + +- Tactic "hnf" now reduces inner beta-iota redexes + (potential source of rare incompatibilities). + +- Tactic "intro H" now reduces beta-iota redexes if these hide a product + (potential source of rare incompatibilities). + +- In Ltac matching on patterns of the form "_ pat1 ... patn" now + behaves like if matching on "?X pat1 ... patn", i.e. accepting "_" + to be instantiated by an applicative term (experimental at this + stage, potential source of incompatibilities). + +- In Ltac matching on goal, types of hypotheses are now interpreted in + the %type scope (possible source of incompatibilities). + +- "change ... in ..." and "simpl ... in ..." now properly consider nested + occurrences (possible source of incompatibilities since this alters + the numbering of occurrences), but do not support nested occurrences. + +- Tactics simpl, vm_compute and native_compute can be given a notation string + to a constant as argument. + +- When given a reference as argument, simpl, vm_compute and + native_compute now strictly interpret it as the head of a pattern + starting with this reference. + +- The "change p with c" tactic semantics changed, now type-checking + "c" at each matching occurrence "t" of the pattern "p", and + converting "t" with "c". + +- Now "appcontext" and "context" behave the same. The old buggy behavior of + "context" can be retrieved at parse time by setting the + "Tactic Compat Context" flag (possible source of incompatibilities). + +- New introduction pattern p/c which applies lemma c on the fly on the + hypothesis under consideration before continuing with introduction pattern p. + +- New introduction pattern [= x1 .. xn] applies "injection as [x1 .. xn]" + on the fly if injection is applicable to the hypothesis under consideration + (idea borrowed from Georges Gonthier). Introduction pattern [=] applies + "discriminate" if a discriminable equality. + +- New introduction patterns * and ** to respectively introduce all forthcoming + dependent variables and all variables/hypotheses dependent or not. + +- Tactic "injection c as ipats" now clears c if c refers to an + hypothesis and moves the resulting equations in the hypotheses + independently of the number of ipats, which has itself to be less + than the number of new hypotheses (possible source of incompatibilities; + former behavior obtainable by "Unset Injection L2R Pattern Order"). + +- Tactic "injection" now automatically simplifies subgoals + "existT n p = existT n p'" into "p = p'" when "n" is in an inductive type for + which a decidable equality scheme has been generated with "Scheme Equality" + (possible source of incompatibilities). + +- New tactic "rewrite_strat" for generalized rewriting with user-defined + strategies, subsuming autorewrite. + +- Injection can now also deduce equality of arguments of sort Prop, by using + the option "Set Injection On Proofs" (disabled by default). Also improved the + error messages. + +- Tactic "subst id" now supports id occurring in dependent local definitions. + +- Bugs fixed about intro-pattern "*" might lead to some rare incompatibilities. + +- New tactical "time" to display time spent executing its argument. + +- Tactics referring or using a constant dependent in a section variable which + has been cleared or renamed in the current goal context now fail + (possible source of incompatibilities solvable by avoiding clearing + the relevant hypotheses). + +- New construct "uconstr:c" and "type_term c" to build untyped terms. + +- Binders in terms defined in Ltac (either "constr" or "uconstr") can + now take their names from identifiers defined in Ltac. As a + consequence, a name cannot be used in a binder "constr:(fun x => + ...)" if an Ltac variable of that name already exists and does not + contain an identifier. Source of occasional incompatibilities. + +- The "refine" tactic now accepts untyped terms built with "uconstr" + so that terms with holes can be constructed piecewise in Ltac. + +- New bullets --, ++, **, ---, +++, ***, ... made available. + +- More informative messages when wrong bullet is used. + +- Bullet suggestion when a subgoal is solved. + +- New tactic "enough", symmetric to "assert", but with subgoals + swapped, as a more friendly replacement of "cut". + +- In destruct/induction, experimental modifier "!" prefixing the + hypothesis name to tell not erasing the hypothesis. + +- Bug fixes in "inversion as" may occasionally lead to incompatibilities. + +- Behavior of introduction patterns -> and <- made more uniform + (hypothesis is cleared, rewrite in hypotheses and conclusion and + erasing the variable when rewriting a variable). + +- New experimental option "Set Standard Proposition Elimination Names" + so that case analysis or induction on schemes in Type containing + propositions now produces "H"-based names. + +- Tactics from plugins are now active only when the corresponding module + is imported (source of incompatibilities, solvable by adding an "Import"; + in the particular case of Omega, use "Require Import OmegaTactic"). + +- Semantics of destruct/induction has been made more regular in some + edge cases, possibly leading to incompatibilities: + + + new goals are now opened when the term does not match a subterm of + the goal and has unresolved holes, while in 8.4 these holes were + turned into existential variables + + when no "at" option is given, the historical semantics which + selects all subterms syntactically identical to the first subterm + matching the given pattern is used + + non-dependent destruct/induction on an hypothesis with premises in + an inductive type with indices is fixed + + residual local definitions are now correctly removed. + +- The rename tactic may now replace variables in parallel. + +- A new "Info" command replaces the "info" tactical discontinued in + v8.4. It still gives informative results in many cases. + +- The "info_auto" tactic is known to be broken and does not print a + trace anymore. Use "Info 1 auto" instead. The same goes for + "info_trivial". On the other hand "info_eauto" still works fine, + while "Info 1 eauto" prints a trivial trace. + +- When using a lemma of the prototypical form "forall A, {a:A & P a}", + "apply" and "apply in" do not instantiate anymore "A" with the + current goal and use "a" as the proof, as they were sometimes doing, + now considering that it is a too powerful decision. + +Program + +- "Solve Obligations using" changed to "Solve Obligations with", + consistent with "Proof with". +- Program Lemma, Definition now respect automatic introduction. +- Program Lemma, Definition, etc.. now interpret "->" like Lemma and + Definition as a non-dependent arrow (potential source of + incompatibility). +- Add/document "Set Hide Obligations" (to hide obligations in the final + term inside an implicit argument) and "Set Shrink Obligations" (to + minimize dependencies of obligations defined by tactics). + +Notations + +- The syntax "x -> y" is now declared at level 99. In particular, it has + now a lower priority than "<->": "A -> B <-> C" is now "A -> (B <-> C)" + (possible source of incompatibilities) +- Notations accept term-providing tactics using the $(...)$ syntax. +- "Bind Scope" can no longer bind "Funclass" and "Sortclass". +- A notation can be given a (compat "8.x") annotation, making it behave + like a "only parsing" notation, but the annotation may lead to eventually + issue warnings or errors in further versions when this notation is used. +- More systematic insertion of spaces as a default for printing + notations ("format" still available to override the default). +- In notations, a level modifier referring to a non-existent variable is + now considered an error rather than silently ignored. + +Tools + +- Option -I now only adds directories to the ml path. +- Option -Q behaves as -R, except that the logical path of any loaded file has + to be fully qualified. +- Option -R no longer adds recursively to the ml path; only the root + directory is added. (Behavior with respect to the load path is + unchanged.) +- Option -nois prevents coq/theories and coq/plugins to be recursively + added to the load path. (Same behavior as with coq/user-contrib.) +- coqdep accepts a -dumpgraph option generating a dot file. +- Makefiles generated through coq_makefile have three new targets "quick" + "checkproofs" and "vio2vo", allowing respectively to asynchronously compile + the files without playing the proof scripts, asynchronously checking + that the quickly generated proofs are correct and generating the object + files from the quickly generated proofs. +- The XML plugin was discontinued and removed from the source. +- A new utility called coqworkmgr can be used to limit the number of + concurrent workers started by independent processes, like make and CoqIDE. + This is of interest for users of the par: goal selector. + +Interfaces + +- CoqIDE supports asynchronous edition of the document, ongoing tasks and + errors are reported in the bottom right window. The number of workers + taking care of processing proofs can be selected with -async-proofs-j. +- CoqIDE highlights in yellow "unsafe" commands such as axiom + declarations, and tactics like "give_up". +- CoqIDE supports Proof General like key bindings; + to activate the PG mode go to Edit -> Preferences -> Editor. + For the documentation see Help -> Help for PG mode. +- CoqIDE automatically retracts the locked area when one edits the + locked text. +- CoqIDE search and replace got regular expressions power. See the + documentation of OCaml's Str module for the supported syntax. +- Many CoqIDE windows, including the query one, are now detachable to + improve usability on multi screen work stations. +- Coqtop/coqc outputs highlighted syntax. Colors can be configured thanks + to the COQ_COLORS environment variable, and their current state can + be displayed with the -list-tags command line option. +- Third party user interfaces can install their main loop in $COQLIB/toploop + and call coqtop with the -toploop flag to select it. + +Internal Infrastructure + +- Many reorganizations in the ocaml source files. For instance, + many internal a.s.t. of Coq are now placed in mli files in + a new directory intf/, for instance constrexpr.mli or glob_term.mli. + More details in dev/doc/changes. + +- The file states/initial.coq does not exist anymore. Instead, coqtop + initially does a "Require" of Prelude.vo (or nothing when given + the options -noinit or -nois). + +- The format of vo files has slightly changed: cf final comments in + checker/cic.mli. + +- The build system does not produce anymore programs named coqtop.opt + and a symbolic link to coqtop. Instead, coqtop is now directly + an executable compiled with the best OCaml compiler available. + The bytecode program coqtop.byte is still produced. Same for other + utilities. + +- Some options of the ./configure script slightly changed: + + * The -coqrunbyteflags and its blank-separated argument is replaced + by option -vmbyteflags which expects a comma-separated argument. + * The -coqtoolsbyteflags option is discontinued, see -no-custom instead. + +Miscellaneous + +- ML plugins now require a "DECLARE PLUGIN \"foo\"" statement. The "foo" name + must be exactly the name of the ML module that will be loaded through a + "Declare ML \"foo\"" command. + +Details of changes in 8.5beta2 +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Logic + +- The VM now supports inductive types with up to 8388851 non-constant + constructors and up to 8388607 constant ones. + +Specification language + +- Syntax "$(tactic)$" changed to "ltac: tactic". + +Tactics + +- A script using the admit tactic can no longer be concluded by either + Qed or Defined. In the first case, Admitted can be used instead. In + the second case, a subproof should be used. +- The easy tactic and the now tactical now have a more predictable + behavior, but they might now discharge some previously unsolved goals. + +Extraction + +- Definitions extracted to Haskell GHC should no longer randomly + segfault when some Coq types cannot be represented by Haskell types. +- Definitions can now be extracted to Json for post-processing. + +Tools + +- Option -I -as has been removed, and option -R -as has been + deprecated. In both cases, option -R can be used instead. +- coq_makefile now generates double-colon rules for rules such as clean. + +API + +- The interface of [change] has changed to take a [change_arg], which + can be built from a [constr] using [make_change_arg]. + +Details of changes in 8.5beta3 +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Vernacular commands + +- New command "Redirect" to redirect the output of a command to a file. +- New command "Undelimit Scope" to remove the delimiter of a scope. +- New option "Strict Universe Declaration", set by default. It enforces the + declaration of all polymorphic universes appearing in a definition when + introducing it. +- New command "Show id" to show goal named id. +- Option "Virtual Machine" removed. + +Tactics + +- New flag "Regular Subst Tactic" which fixes "subst" in situations where + it failed to substitute all substitutable equations or failed to simplify + cycles, or accidentally unfolded local definitions (flag is off by default). +- New flag "Loose Hint Behavior" to handle hints loaded but not imported in a + special way. It accepts three distinct flags: + * "Lax", which is the default one, sets the old behavior, i.e. a non-imported + hint behaves the same as an imported one. + * "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 an eauto run that + will eventually fail and backtrack. + * "Strict" changes the behavior of an unloaded hint to the one of the fail + tactic, allowing to emulate the hopefully future import-scoped hint mechanism. +- New compatibility flag "Universal Lemma Under Conjunction" which + let tactics working under conjunctions apply sublemmas of the form + "forall A, ... -> A". +- New compatibility flag "Bracketing Last Introduction Pattern" which can be + set so that the last disjunctive-conjunctive introduction pattern given to + "intros" automatically complete the introduction of its subcomponents, as the + the disjunctive-conjunctive introduction patterns in non-terminal position + already do. +- New flag "Shrink Abstract" that minimalizes proofs generated by the abstract + tactical w.r.t. variables appearing in the body of the proof. + +Program + +- The "Shrink Obligations" flag now applies to all obligations, not only those + solved by the automatic tactic. +- Importing Program no longer overrides the "exists" tactic (potential source + of incompatibilities). +- Hints costs are now correctly taken into account (potential source of + incompatibilities). +- Documented the Hint Cut command that allows control of the + proof-search during typeclass resolution (see reference manual). + +API + +- Some functions from pretyping/typing.ml and their derivatives were potential + source of evarmap leaks, as they dropped their resulting evarmap. The + situation was clarified by renaming them according to a ``unsafe_*`` scheme. Their + sound variant is likewise renamed to their old name. The following renamings + were made. + + * ``Typing.type_of`` -> ``unsafe_type_of`` + * ``Typing.e_type_of`` -> ``type_of`` + * A new ``e_type_of`` function that matches the ``e_`` prefix policy + * ``Tacmach.pf_type_of`` -> ``pf_unsafe_type_of`` + * A new safe ``pf_type_of`` function. + + All uses of ``unsafe_*`` functions should be eventually eliminated. + +Tools + +- Added an option -w to control the output of coqtop warnings. +- Configure now takes an optional -native-compiler (yes|no) flag replacing + -no-native-compiler. The new flag is set to no by default under Windows. +- Flag -no-native-compiler was removed and became the default for coqc. If + precompilation of files for native conversion test is desired, use + -native-compiler. +- The -compile command-line option now takes the full path of the considered + file, including the ".v" extension, and outputs a warning if such an extension + is lacking. +- The -require and -load-vernac-object command-line options now take a logical + path of a given library rather than a physical path, thus they behave like + Require [Import] path. +- The -vm command-line option has been removed. + +Standard Library + + - There is now a Coq.Compat.Coq84 library, which sets the various compatibility + options and does a few redefinitions to make Coq behave more like Coq v8.4. + The standard way of putting Coq in v8.4 compatibility mode is to pass the command + line flags "-require Coq.Compat.Coq84 -compat 8.4". + +Details of changes in 8.5 +~~~~~~~~~~~~~~~~~~~~~~~~~ + +Tools + +- Flag "-compat 8.4" now loads Coq.Compat.Coq84. The standard way of + putting Coq in v8.4 compatibility mode is to pass the command line flag + "-compat 8.4". It can be followed by "-require Coq.Compat.AdmitAxiom" + if the 8.4 behavior of admit is needed, in which case it uses an axiom. + +Specification language + +- Syntax "$(tactic)$" changed to "ltac:(tactic)". + +Tactics + +- Syntax "destruct !hyp" changed to "destruct (hyp)", and similarly + for induction (rare source of incompatibilities easily solvable by + removing parentheses around "hyp" when not for the purpose of keeping + the hypothesis). +- Syntax "p/c" for on-the-fly application of a lemma c before + introducing along pattern p changed to p%c1..%cn. The feature and + syntax are in experimental stage. +- "Proof using" does not clear unused section variables. +- Tactic "refine" has been changed back to the 8.4 behavior of shelving subgoals + that occur in other subgoals. The "refine" tactic of 8.5beta3 has been + renamed "simple refine"; it does not shelve any subgoal. +- New tactical "unshelve tac" which grab existential variables put on + the tactic shelve by the execution of "tac". + +Details of changes in 8.5pl1 +~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Critical bugfix + +- The subterm relation for the guard condition was incorrectly defined on + primitive projections (#4588) + +Plugin development tools + +- add a .merlin target to the makefile + +Various performance improvements (time, space used by .vo files) + +Other bugfixes + +- Fix order of arguments to Big.compare_case in ExtrOcamlZBigInt.v +- Added compatibility coercions from Specif.v which were present in Coq 8.4. +- Fixing a source of inefficiency and an artificial dependency in the printer in the congruence tactic. +- Allow to unset the refinement mode of Instance in ML +- Fixing an incorrect use of prod_appvect on a term which was not a product in setoid_rewrite. +- Add -compat 8.4 econstructor tactics, and tests +- Add compatibility Nonrecursive Elimination Schemes +- Fixing the "No applicable tactic" non informative error message regression on apply. +- Univs: fix get_current_context (bug #4603, part I) +- Fix a bug in Program coercion code +- Fix handling of arity of definitional classes. +- #4630: Some tactics are 20x slower in 8.5 than 8.4. +- #4627: records with no declared arity can be template polymorphic. +- #4623: set tactic too weak with universes (regression) +- Fix incorrect behavior of CS resolution +- #4591: Uncaught exception in directory browsing. +- CoqIDE is more resilient to initialization errors. +- #4614: "Fully check the document" is uninterruptable. +- Try eta-expansion of records only on non-recursive ones +- Fix bug when a sort is ascribed to a Record +- Primitive projections: protect kernel from erroneous definitions. +- Fixed bug #4533 with previous Keyed Unification commit +- Win: kill unreliable hence do not waitpid after kill -9 (Close #4369) +- Fix strategy of Keyed Unification +- #4608: Anomaly "output_value: abstract value (outside heap)". +- #4607: do not read native code files if native compiler was disabled. +- #4105: poor escaping in the protocol between CoqIDE and coqtop. +- #4596: [rewrite] broke in the past few weeks. +- #4533 (partial): respect declared global transparency of projections in unification.ml +- #4544: Backtrack on using full betaiota reduction during keyed unification. +- #4540: CoqIDE bottom progress bar does not update. +- Fix regression from 8.4 in reflexivity +- #4580: [Set Refine Instance Mode] also used for Program Instance. +- #4582: cannot override notation [ x ]. MAY CREATE INCOMPATIBILITIES, see #4683. +- STM: Print/Extraction have to be skipped if -quick +- #4542: CoqIDE: STOP button also stops workers +- STM: classify some variants of Instance as regular `` `Fork `` nodes. +- #4574: Anomaly: Uncaught exception Invalid_argument("splay_arity"). +- Do not give a name to anonymous evars anymore. See bug #4547. +- STM: always stock in vio files the first node (state) of a proof +- STM: not delegate proofs that contain Vernac(Module|Require|Import), #4530 +- Don't fail fatally if PATH is not set. +- #4537: Coq 8.5 is slower in typeclass resolution. +- #4522: Incorrect "Warning..." on windows. +- #4373: coqdep does not know about .vio files. +- #3826: "Incompatible module types" is uninformative. +- #4495: Failed assertion in metasyntax.ml. +- #4511: evar tactic can create non-typed evars. +- #4503: mixing universe polymorphic and monomorphic variables and definitions in sections is unsupported. +- #4519: oops, global shadowed local universe level bindings. +- #4506: Anomaly: File "pretyping/indrec.ml", line 169, characters 14-20: Assertion failed. +- #4548: Coqide crashes when going back one command + +Details of changes in 8.5pl2 +~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Critical bugfix + +- Checksums of .vo files dependencies were not correctly checked. +- Unicode-to-ASCII translation was not injective, leading in a soundness bug in + the native compiler. + +Other bugfixes + +- #4097: more efficient occur-check in presence of primitive projections +- #4398: type_scope used consistently in "match goal". +- #4450: eauto does not work with polymorphic lemmas +- #4677: fix alpha-conversion in notations needing eta-expansion. +- Fully preserve initial order of hypotheses in "Regular Subst Tactic" mode. +- #4644: a regression in unification. +- #4725: Function (Error: Conversion test raised an anomaly) and Program + (Error: Cannot infer this placeholder of type) +- #4747: Problem building Coq 8.5pl1 with OCaml 4.03.0: Fatal warnings +- #4752: CoqIDE crash on files not ended by ".v". +- #4777: printing inefficiency with implicit arguments +- #4818: "Admitted" fails due to undefined universe anomaly after calling + "destruct" +- #4823: remote counter: avoid thread race on sockets +- #4841: -verbose flag changed semantics in 8.5, is much harder to use +- #4851: [nsatz] cannot handle duplicated hypotheses +- #4858: Anomaly: Uncaught exception Failure("hd"). Please report. in variant + of nsatz +- #4880: [nsatz_compute] generates invalid certificates if given redundant + hypotheses +- #4881: synchronizing "Declare Implicit Tactic" with backtrack. +- #4882: anomaly with Declare Implicit Tactic on hole of type with evars +- Fix use of "Declare Implicit Tactic" in refine. + triggered by CoqIDE +- #4069, #4718: congruence fails when universes are involved. + +Universes + +- Disallow silently dropping universe instances applied to variables + (forward compatible) +- Allow explicit universe instances on notations, when they can apply + to the head reference of their expansion. + +Build infrastructure + +- New update on how to find camlp5 binary and library at configure time. + +Details of changes in 8.5pl3 +~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Critical bugfix + +- #4876: Guard checker incompleteness when using primitive projections + +Other bugfixes + +- #4780: Induction with universe polymorphism on was creating ill-typed terms. +- #4673: regression in setoid_rewrite, unfolding let-ins for type unification. +- #4754: Regression in setoid_rewrite, allow postponed unification problems to remain. +- #4769: Anomaly with universe polymorphic schemes defined inside sections. +- #3886: Program: duplicate obligations of mutual fixpoints. +- #4994: Documentation typo. +- #5008: Use the "md5" command on OpenBSD. +- #5007: Do not assume the "TERM" environment variable is always set. +- #4606: Output a break before a list only if there was an empty line. +- #5001: metas not cleaned properly in clenv_refine_in. +- #2336: incorrect glob data for module symbols (bug #2336). +- #4832: Remove extraneous dot in error message. +- Anomaly in printing a unification error message. +- #4947: Options which take string arguments are not backwards compatible. +- #4156: micromega cache files are now hidden files. +- #4871: interrupting par:abstract kills coqtop. +- #5043: [Admitted] lemmas pick up section variables. +- Fix name of internal refine ("simple refine"). +- #5062: probably a typo in Strict Proofs mode. +- #5065: Anomaly: Not a proof by induction. +- Restore native compiler optimizations, they were disabled since 8.5! +- #5077: failure on typing a fixpoint with evars in its type. +- Fix recursive notation bug. +- #5095: non relevant too strict test in let-in abstraction. +- Ensuring that the evar name is preserved by "rename". +- #4887: confusion between using and with in documentation of firstorder. +- Bug in subst with let-ins. +- #4762: eauto weaker than auto. +- Remove if_then_else (was buggy). Use tryif instead. +- #4970: confusion between special "{" and non special "{{" in notations. +- #4529: primitive projections unfolding. +- #4416: Incorrect "Error: Incorrect number of goals". +- #4863: abstract in typeclass hint fails. +- #5123: unshelve can impact typeclass resolution +- Fix a collision about the meta-variable ".." in recursive notations. +- Fix printing of info_auto. +- #3209: Not_found due to an occur-check cycle. +- #5097: status of evars refined by "clear" in ltac: closed wrt evars. +- #5150: Missing dependency of the test-suite subsystems in prerequisite. +- Fix a bug in error printing of unif constraints +- #3941: Do not stop propagation of signals when Coq is busy. +- #4822: Incorrect assertion in cbn. +- #3479 parsing of "{" and "}" when a keyword starts with "{" or "}". +- #5127: Memory corruption with the VM. +- #5102: bullets parsing broken by calls to parse_entry. + +Various documentation improvements + +Version 8.4 +----------- + +Summary of changes +~~~~~~~~~~~~~~~~~~ + +Coq version 8.4 contains the result of three long-term projects: a new +modular library of arithmetic by Pierre Letouzey, a new proof engine by +Arnaud Spiwack and a new communication protocol for |CoqIDE| by Vincent +Gross. + +The new modular library of arithmetic extends, generalizes and unifies +the existing libraries on Peano arithmetic (types nat, N and BigN), +positive arithmetic (type positive), integer arithmetic (Z and BigZ) and +machine word arithmetic (type Int31). It provides with unified notations +(e.g. systematic use of add and mul for denoting the addition and +multiplication operators), systematic and generic development of +operators and properties of these operators for all the types mentioned +above, including gcd, pcm, power, square root, base 2 logarithm, +division, modulo, bitwise operations, logical shifts, comparisons, +iterators, ... + +The most visible feature of the new proof engine is the support for +structured scripts (bullets and proof brackets) but, even if yet not +user-available, the new engine also provides the basis for refining +existential variables using tactics, for applying tactics to several +goals simultaneously, for reordering goals, all features which are +planned for the next release. The new proof engine forced Pierre Letouzey +to reimplement info and Show Script differently. + +Before version 8.4, |CoqIDE| was linked to |Coq| with the graphical +interface living in a separate thread. From version 8.4, |CoqIDE| is a +separate process communicating with |Coq| through a textual channel. This +allows for a more robust interfacing, the ability to interrupt |Coq| +without interrupting the interface, and the ability to manage several +sessions in parallel. Relying on the infrastructure work made by Vincent +Gross, Pierre Letouzey, Pierre Boutillier and Pierre-Marie Pédrot +contributed many various refinements of |CoqIDE|. + +Coq 8.4 also comes with a bunch of various smaller-scale changes +and improvements regarding the different components of the system. + +The underlying logic has been extended with :math:`\eta`-conversion +thanks to Hugo Herbelin, Stéphane Glondu and Benjamin Grégoire. The +addition of :math:`\eta`-conversion is justified by the confidence that +the formulation of the Calculus of Inductive Constructions based on +typed equality (such as the one considered in Lee and Werner to build a +set-theoretic model of CIC :cite:`LeeWerner11`) is +applicable to the concrete implementation of |Coq|. + +The underlying logic benefited also from a refinement of the guard +condition for fixpoints by Pierre Boutillier, the point being that it is +safe to propagate the information about structurally smaller arguments +through :math:`\beta`-redexes that are blocked by the “match” +construction (blocked commutative cuts). + +Relying on the added permissiveness of the guard condition, Hugo +Herbelin could extend the pattern matching compilation algorithm so that +matching over a sequence of terms involving dependencies of a term or of +the indices of the type of a term in the type of other terms is +systematically supported. + +Regarding the high-level specification language, Pierre Boutillier +introduced the ability to give implicit arguments to anonymous +functions, Hugo Herbelin introduced the ability to define notations with +several binders (e.g. ``exists x y z, P``), Matthieu Sozeau made the +typeclass inference mechanism more robust and predictable, Enrico +Tassi introduced a command Arguments that generalizes Implicit Arguments +and Arguments Scope for assigning various properties to arguments of +constants. Various improvements in the type inference algorithm were +provided by Matthieu Sozeau and Hugo Herbelin with contributions from +Enrico Tassi. + +Regarding tactics, Hugo Herbelin introduced support for referring to +expressions occurring in the goal by pattern in tactics such as set or +destruct. Hugo Herbelin also relied on ideas from Chung-Kil Hur’s Heq +plugin to introduce automatic computation of occurrences to generalize +when using destruct and induction on types with indices. Stéphane Glondu +introduced new tactics :tacn:`constr_eq`, :tacn:`is_evar`, and :tacn:`has_evar`, to be used +when writing complex tactics. Enrico Tassi added support to fine-tuning +the behavior of :tacn:`simpl`. Enrico Tassi added the ability to specify over +which variables of a section a lemma has to be exactly generalized. +Pierre Letouzey added a tactic timeout and the interruptibility of +:tacn:`vm_compute`. Bug fixes and miscellaneous improvements of the tactic +language came from Hugo Herbelin, Pierre Letouzey and Matthieu Sozeau. + +Regarding decision tactics, Loïc Pottier maintained nsatz, moving in +particular to a typeclass based reification of goals while Frédéric +Besson maintained Micromega, adding in particular support for division. + +Regarding vernacular commands, Stéphane Glondu provided new commands to +analyze the structure of type universes. + +Regarding libraries, a new library about lists of a given length (called +vectors) has been provided by Pierre Boutillier. A new instance of +finite sets based on Red-Black trees and provided by Andrew Appel has +been adapted for the standard library by Pierre Letouzey. In the library +of real analysis, Yves Bertot changed the definition of :math:`\pi` and +provided a proof of the long-standing fact yet remaining unproved in +this library, namely that :math:`sin \frac{\pi}{2} = +1`. + +Pierre Corbineau maintained the Mathematical Proof Language (C-zar). + +Bruno Barras and Benjamin Grégoire maintained the call-by-value +reduction machines. + +The extraction mechanism benefited from several improvements provided by +Pierre Letouzey. + +Pierre Letouzey maintained the module system, with contributions from +Élie Soubiran. + +Julien Forest maintained the Function command. + +Matthieu Sozeau maintained the setoid rewriting mechanism. + +Coq related tools have been upgraded too. In particular, coq\_makefile +has been largely revised by Pierre Boutillier. Also, patches from Adam +Chlipala for coqdoc have been integrated by Pierre Boutillier. + +Bruno Barras and Pierre Letouzey maintained the `coqchk` checker. + +Pierre Courtieu and Arnaud Spiwack contributed new features for using +Coq through Proof General. + +The Dp plugin has been removed. Use the plugin provided with Why 3 +instead (http://why3.lri.fr/). + +Under the hood, the |Coq| architecture benefited from improvements in +terms of efficiency and robustness, especially regarding universes +management and existential variables management, thanks to Pierre +Letouzey and Yann Régis-Gianas with contributions from Stéphane Glondu +and Matthias Puech. The build system is maintained by Pierre Letouzey +with contributions from Stéphane Glondu and Pierre Boutillier. + +A new backtracking mechanism simplifying the task of external interfaces +has been designed by Pierre Letouzey. + +The general maintenance was done by Pierre Letouzey, Hugo Herbelin, +Pierre Boutillier, Matthieu Sozeau and Stéphane Glondu with also +specific contributions from Guillaume Melquiond, Julien Narboux and +Pierre-Marie Pédrot. + +Packaging tools were provided by Pierre Letouzey (Windows), Pierre +Boutillier (MacOS), Stéphane Glondu (Debian). Releasing, testing and +benchmarking support was provided by Jean-Marc Notin. + +Many suggestions for improvements were motivated by feedback from users, +on either the bug tracker or the Coq-Club mailing list. Special thanks +are going to the users who contributed patches, starting with Tom +Prince. Other patch contributors include Cédric Auger, David Baelde, Dan +Grayson, Paolo Herms, Robbert Krebbers, Marc Lasson, Hendrik Tews and +Eelis van der Weegen. + +| Paris, December 2011 +| Hugo Herbelin +| + +Potential sources of incompatibilities +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The main known incompatibilities between 8.3 and 8.4 are consequences +of the following changes: + +- The reorganization of the library of numbers: + + Several definitions have new names or are defined in modules of + different names, but a special care has been taken to have this + renaming transparent for the user thanks to compatibility notations. + + However some definitions have changed, what might require some + adaptations. The most noticeable examples are: + + + The "?=" notation which now bind to Pos.compare rather than former + Pcompare (now Pos.compare_cont). + + Changes in names may induce different automatically generated + names in proof scripts (e.g. when issuing "destruct Z_le_gt_dec"). + + Z.add has a new definition, hence, applying "simpl" on subterms of + its body might give different results than before. + + BigN.shiftl and BigN.shiftr have reversed arguments order, the + power function in BigN now takes two BigN. + +- Other changes in libraries: + + + The definition of functions over "vectors" (list of fixed length) + have changed. + + TheoryList.v has been removed. + +- Slight changes in tactics: + + + Less unfolding of fixpoints when applying destruct or inversion on + a fixpoint hiding an inductive type (add an extra call to simpl to + preserve compatibility). + + Less unexpected local definitions when applying "destruct" + (incompatibilities solvable by adapting name hypotheses). + + Tactic "apply" might succeed more often, e.g. by now solving + pattern-matching of the form ?f x y = g(x,y) (compatibility + ensured by using "Unset Tactic Pattern Unification"), but also + because it supports (full) betaiota (using "simple apply" might + then help). + + Tactic autorewrite does no longer instantiate pre-existing + existential variables. + + Tactic "info" is now available only for auto, eauto and trivial. + +- Miscellaneous changes: + + + The command "Load" is now atomic for backtracking (use "Unset + Atomic Load" for compatibility). + +Details of changes in 8.4beta +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Logic + +- Standard eta-conversion now supported (dependent product only). +- Guard condition improvement: subterm property is propagated through beta-redex + blocked by pattern-matching, as in "(match v with C .. => fun x => u end) x"; + this allows for instance to use "rewrite ... in ..." without breaking + the guard condition. + +Specification language and notations + +- Maximal implicit arguments can now be set locally by { }. The registration + traverses fixpoints and lambdas. Because there is conversion in types, + maximal implicit arguments are not taken into account in partial + applications (use eta expanded form with explicit { } instead). +- Added support for recursive notations with binders (allows for instance + to write "exists x y z, P"). +- Structure/Record printing can be disable by "Unset Printing Records". + In addition, it can be controlled on type by type basis using + "Add Printing Record" or "Add Printing Constructor". +- Pattern-matching compilation algorithm: in "match x, y with ... end", + possible dependencies of x (or of the indices of its type) in the type + of y are now taken into account. + +Tactics + +- New proof engine. +- Scripts can now be structured thanks to bullets - * + and to subgoal + delimitation via { }. Note: for use with Proof General, a cvs version of + Proof General no older than mid-July 2011 is currently required. +- Support for tactical "info" is suspended. +- Support for command "Show Script" is suspended. +- New tactics constr_eq, is_evar and has_evar for use in Ltac (DOC TODO). +- Removed the two-argument variant of "decide equality". +- New experimental tactical "timeout <n> <tac>". Since <n> is a time + in second for the moment, this feature should rather be avoided + in scripts meant to be machine-independent. +- Fix in "destruct": removal of unexpected local definitions in context might + result in some rare incompatibilities (solvable by adapting name hypotheses). +- Introduction pattern "_" made more robust. +- Tactic (and Eval command) vm_compute can now be interrupted via Ctrl-C. +- Unification in "apply" supports unification of patterns of the form + ?f x y = g(x,y) (compatibility ensured by using + "Unset Tactic Pattern Unification"). It also supports (full) betaiota. +- Tactic autorewrite does no longer instantiate pre-existing + existential variables (theoretical source of possible incompatibilities). +- Tactic "dependent rewrite" now supports equality in "sig". +- Tactic omega now understands Zpred (wish #1912) and can prove any goal + from a context containing an arithmetical contradiction (wish #2236). +- Using "auto with nocore" disables the use of the "core" database (wish #2188). + This pseudo-database "nocore" can also be used with trivial and eauto. +- Tactics "set", "destruct" and "induction" accepts incomplete terms and + use the goal to complete the pattern assuming it is non ambiguous. +- When used on arguments with a dependent type, tactics such as + "destruct", "induction", "case", "elim", etc. now try to abstract + automatically the dependencies over the arguments of the types + (based on initial ideas from Chung-Kil Hur, extension to nested + dependencies suggested by Dan Grayson) +- Tactic "injection" now failing on an equality showing no constructors while + it was formerly generalizing again the goal over the given equality. +- In Ltac, the "context [...]" syntax has now a variant "appcontext [...]" + allowing to match partial applications in larger applications. +- When applying destruct or inversion on a fixpoint hiding an inductive + type, recursive calls to the fixpoint now remain folded by default (rare + source of incompatibility generally solvable by adding a call to simpl). +- In an ltac pattern containing a "match", a final "| _ => _" branch could be + used now instead of enumerating all remaining constructors. Moreover, the + pattern "match _ with _ => _ end" now allows to match any "match". A "in" + annotation can also be added to restrict to a precise inductive type. +- The behavior of "simpl" can be tuned using the "Arguments" vernacular. + In particular constants can be marked so that they are always/never unfolded + by "simpl", or unfolded only when a set of arguments evaluates to a + constructor. Last one can mark a constant so that it is unfolded only if the + simplified term does not expose a match in head position. + +Vernacular commands + +- It is now mandatory to have a space (or tabulation or newline or end-of-file) + after a "." ending a sentence. +- In SearchAbout, the [ ] delimiters are now optional. +- New command "Add/Remove Search Blacklist <substring> ...": + a Search or SearchAbout or similar query will never mention lemmas + whose qualified names contain any of the declared substrings. + The default blacklisted substrings are ``_subproof``, ``Private_``. +- When the output file of "Print Universes" ends in ".dot" or ".gv", + the universe graph is printed in the DOT language, and can be + processed by Graphviz tools. +- New command "Print Sorted Universes". +- The undocumented and obsolete option "Set/Unset Boxed Definitions" has + been removed, as well as syntaxes like "Boxed Fixpoint foo". +- A new option "Set Default Timeout n / Unset Default Timeout". +- Qed now uses information from the reduction tactics used in proof script + to avoid conversion at Qed time to go into a very long computation. +- New command "Show Goal ident" to display the statement of a goal, even + a closed one (available from Proof General). +- Command "Proof" accept a new modifier "using" to force generalization + over a given list of section variables at section ending (DOC TODO). +- New command "Arguments" generalizing "Implicit Arguments" and + "Arguments Scope" and that also allows to rename the parameters of a + definition and to tune the behavior of the tactic "simpl". + +Module System + +- During subtyping checks, an opaque constant in a module type could now + be implemented by anything of the right type, even if bodies differ. + Said otherwise, with respect to subtyping, an opaque constant behaves + just as a parameter. Coqchk was already implementing this, but not coqtop. +- The inlining done during application of functors can now be controlled + more precisely, by the annotations (no inline) or (inline at level XX). + With the latter annotation, only functor parameters whose levels + are lower or equal than XX will be inlined. + The level of a parameter can be fixed by "Parameter Inline(30) foo". + When levels aren't given, the default value is 100. One can also use + the flag "Set Inline Level ..." to set a level (DOC TODO). +- Print Assumptions should now handle correctly opaque modules (#2168). +- Print Module (Type) now tries to print more details, such as types and + bodies of the module elements. Note that Print Module Type could be + used on a module to display only its interface. The option + "Set Short Module Printing" could be used to switch back to the earlier + behavior were only field names were displayed. + +Libraries + +- Extension of the abstract part of Numbers, which now provide axiomatizations + and results about many more integer functions, such as pow, gcd, lcm, sqrt, + log2 and bitwise functions. These functions are implemented for nat, N, BigN, + Z, BigZ. See in particular file NPeano for new functions about nat. + +- The definition of types positive, N, Z is now in file BinNums.v + +- Major reorganization of ZArith. The initial file ZArith/BinInt.v now contains + an internal module Z implementing the Numbers interface for integers. + This module Z regroups: + + * all functions over type Z : Z.add, Z.mul, ... + * the minimal proofs of specifications for these functions : Z.add_0_l, ... + * an instantation of all derived properties proved generically in Numbers : + Z.add_comm, Z.add_assoc, ... + + A large part of ZArith is now simply compatibility notations, for instance + Zplus_comm is an alias for Z.add_comm. The direct use of module Z is now + recommended instead of relying on these compatibility notations. + +- Similar major reorganization of NArith, via a module N in NArith/BinNat.v + +- Concerning the positive datatype, BinPos.v is now in a specific directory + PArith, and contains an internal submodule Pos. We regroup there functions + such as Pos.add Pos.mul etc as well as many results about them. These results + are here proved directly (no Number interface for strictly positive numbers). + +- Note that in spite of the compatibility layers, all these reorganizations + may induce some marginal incompatibilies in scripts. In particular: + + * the "?=" notation for positive now refers to a binary function Pos.compare, + instead of the infamous ternary Pcompare (now Pos.compare_cont). + * some hypothesis names generated by the system may changed (typically for + a "destruct Z_le_gt_dec") since naming is done after the short name of + the head predicate (here now "le" in module Z instead of "Zle", etc). + * the internals of Z.add has changed, now relying of Z.pos_sub. + +- Also note these new notations: + + * "<?" "<=?" "=?" for boolean tests such as Z.ltb Z.leb Z.eqb. + * "÷" for the alternative integer division Z.quot implementing the Truncate + convention (former ZOdiv), while the notation for the Coq usual division + Z.div implementing the Flooring convention remains "/". Their corresponding + modulo functions are Z.rem (no notations) for Z.quot and Z.modulo (infix + "mod" notation) for Z.div. + +- Lemmas about conversions between these datatypes are also organized + in modules, see for instance modules Z2Nat, N2Z, etc. + +- When creating BigN, the macro-generated part NMake_gen is much smaller. + The generic part NMake has been reworked and improved. Some changes + may introduce incompatibilities. In particular, the order of the arguments + for BigN.shiftl and BigN.shiftr is now reversed: the number to shift now + comes first. By default, the power function now takes two BigN. + +- Creation of Vector, an independent library for lists indexed by their length. + Vectors' names overwrite lists' one so you should not "Import" the library. + All old names changed: function names follow the ocaml ones and, for example, + Vcons becomes Vector.cons. You can get [..;..;..]-style notations by importing + Vector.VectorNotations. + +- Removal of TheoryList. Requiring List instead should work most of the time. + +- New syntax "rew Heq in H" and "rew <- Heq in H" for eq_rect and + eq_rect_r (available by importing module EqNotations). + +- Wf.iter_nat is now Peano.nat_iter (with an implicit type argument). + +Internal infrastructure + +- Opaque proofs are now loaded lazily by default. This allows to be almost as + fast as -dont-load-proofs, while being safer (no creation of axioms) and + avoiding feature restrictions (Print and Print Assumptions work ok). +- Revised hash-consing code allowing more sharing of memory +- Experimental support added for camlp4 (the one provided alongside ocaml), + simply pass option -usecamlp4 to ./configure. By default camlp5 is used. +- Revised build system: no more stages in Makefile thanks to some recursive + aspect of recent gnu make, use of vo.itarget files containing .v to compile + for both make and ocamlbuild, etc. +- Support of cross-compilation via mingw from unix toward Windows, + contact P. Letouzey for more informations. +- New Makefile rules mli-doc to make html of mli in dev/doc/html and + full-stdlib to get a (huge) pdf reflecting the whole standard library. + +Extraction + +- By default, opaque terms are now truly considered opaque by extraction: + instead of accessing their body, they are now considered as axioms. + The previous behaviour can be reactivated via the option + "Set Extraction AccessOpaque". +- The pretty-printer for Haskell now produces layout-independent code +- A new command "Separate Extraction cst1 cst2 ..." that mixes a + minimal extracted environment a la "Recursive Extraction" and the + production of several files (one per coq source) a la "Extraction Library" + (DOC TODO). +- New option "Set/Unset Extraction KeepSingleton" for preventing the + extraction to optimize singleton container types (DOC TODO). +- The extraction now identifies and properly rejects a particular case of + universe polymorphism it cannot handle yet (the pair (I,I) being Prop). +- Support of anonymous fields in record (#2555). + +CoqIDE + +- Coqide now runs coqtop as separated process, making it more robust: + coqtop subprocess can be interrupted, or even killed and relaunched + (cf button "Restart Coq", ex-"Go to Start"). For allowing such + interrupts, the Windows version of coqide now requires Windows >= XP + SP1. +- The communication between CoqIDE and Coqtop is now done via a dialect + of XML (DOC TODO). +- The backtrack engine of CoqIDE has been reworked, it now uses the + "Backtrack" command similarly to Proof General. +- The Coqide parsing of sentences has be reworked and now supports + tactic delimitation via { }. +- Coqide now accepts the Abort command (wish #2357). +- Coqide can read coq_makefile files as "project file" and use it to + set automatically options to send to coqtop. +- Preference files have moved to $XDG_CONFIG_HOME/coq and accelerators + are not stored as a list anymore. + +Tools + +- Coq now searches directories specified in COQPATH, $XDG_DATA_HOME/coq, + $XDG_DATA_DIRS/coq, and user-contribs before the standard library. + +- Coq rc file has moved to $XDG_CONFIG_HOME/coq. + +- Major changes to coq_makefile: + + * mli/mlpack/mllib taken into account, ml not preproccessed anymore, ml4 work; + * mlihtml generates doc of mli, install-doc install the html doc in DOCDIR + with the same policy as vo in COQLIB; + * More variables are given by coqtop -config, others are defined only if the + users doesn't have defined them elsewhere. Consequently, generated makefile + should work directly on any architecture; + * Packagers can take advantage of $(DSTROOT) introduction. Installation can + be made in $XDG_DATA_HOME/coq; + * -arg option allows to send option as argument to coqc. + +Details of changes in 8.4beta2 +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Vernacular commands + +- Commands "Back" and "BackTo" are now handling the proof states. They may + perform some extra steps of backtrack to avoid states where the proof + state is unavailable (typically a closed proof). +- The commands "Suspend" and "Resume" have been removed. +- A basic Show Script has been reintroduced (no indentation). +- New command "Set Parsing Explicit" for deactivating parsing (and printing) + of implicit arguments (useful for teaching). +- New command "Grab Existential Variables" to transform the unresolved evars + at the end of a proof into goals. + +Tactics + +- Still no general "info" tactical, but new specific tactics info_auto, + info_eauto, info_trivial which provides information on the proofs found + by auto/eauto/trivial. Display of these details could also be activated by + "Set Info Auto"/"Set Info Eauto"/"Set Info Trivial". +- Details on everything tried by auto/eauto/trivial during a proof search + could be obtained by "debug auto", "debug eauto", "debug trivial" or by a + global "Set Debug Auto"/"Set Debug Eauto"/"Set Debug Trivial". +- New command "r string" in Ltac debugger that interprets "idtac + string" in Ltac code as a breakpoint and jumps to its next use. +- Tactics from the Dp plugin (simplify, ergo, yices, cvc3, z3, cvcl, + harvey, zenon, gwhy) have been removed, since Why2 has not been + maintained for the last few years. The Why3 plugin should be a suitable + replacement in most cases. + +Libraries + +- MSetRBT: a new implementation of MSets via Red-Black trees (initial + contribution by Andrew Appel). +- MSetAVL: for maximal sharing with the new MSetRBT, the argument order + of Node has changed (this should be transparent to regular MSets users). + +Module System + +- The names of modules (and module types) are now in a fully separated + namespace from ordinary definitions: "Definition E:=0. Module E. End E." + is now accepted. + +CoqIDE + +- Coqide now supports the "Restart" command, and "Undo" (with a warning). + Better support for "Abort". + +Details of changes in 8.4 +~~~~~~~~~~~~~~~~~~~~~~~~~ + +Vernacular commands + +- The "Reset" command is now supported again in files given to coqc or Load. +- "Show Script" now indents again the displayed scripts. It can also work + correctly across Load'ed files if the option "Unset Atomic Load" is used. +- "Open Scope" can now be given the delimiter (e.g. Z) instead of the full + scope name (e.g. Z_scope). + +Notations + +- Most compatibility notations of the standard library are now tagged as + (compat xyz), where xyz is a former Coq version, for instance "8.3". + These notations behave as (only parsing) notations, except that they may + triggers warnings (or errors) when used while Coq is not in a corresponding + -compat mode. +- To activate these compatibility warnings, use "Set Verbose Compat Notations" + or the command-line flag -verbose-compat-notations. +- For a strict mode without these compatibility notations, use + "Unset Compat Notations" or the command-line flag -no-compat-notations. + +Tactics + +- An annotation "eqn:H" or "eqn:?" can be added to a "destruct" + or "induction" to make it generate equations in the spirit of "case_eq". + The former syntax "_eqn" is discontinued. +- The name of the hypothesis introduced by tactic "remember" can be + set via the new syntax "remember t as x eqn:H" (wish #2489). + +Libraries + +- Reals: changed definition of PI, no more axiom about sin(PI/2). +- SetoidPermutation: a notion of permutation for lists modulo a setoid equality. +- BigN: fixed the ocaml code doing the parsing/printing of big numbers. +- List: a couple of lemmas added especially about no-duplication, partitions. +- Init: Removal of the coercions between variants of sigma-types and + subset types (possible source of incompatibility). + +Version 8.3 +----------- + +Summary of changes +~~~~~~~~~~~~~~~~~~ + +Coq version 8.3 is before all a transition version with refinements or +extensions of the existing features and libraries and a new tactic nsatz +based on Hilbert’s Nullstellensatz for deciding systems of equations +over rings. + +With respect to libraries, the main evolutions are due to Pierre +Letouzey with a rewriting of the library of finite sets FSets and a new +round of evolutions in the modular development of arithmetic (library +Numbers). The reason for making FSets evolve is that the computational +and logical contents were quite intertwined in the original +implementation, leading in some cases to longer computations than +expected and this problem is solved in the new MSets implementation. As +for the modular arithmetic library, it was only dealing with the basic +arithmetic operators in the former version and its current extension +adds the standard theory of the division, min and max functions, all +made available for free to any implementation of :math:`\mathbb{N}`, +:math:`\mathbb{Z}` or :math:`\mathbb{Z}/n\mathbb{Z}`. + +The main other evolutions of the library are due to Hugo Herbelin who +made a revision of the sorting library (including a certified +merge-sort) and to Guillaume Melquiond who slightly revised and cleaned +up the library of reals. + +The module system evolved significantly. Besides the resolution of some +efficiency issues and a more flexible construction of module types, Élie +Soubiran brought a new model of name equivalence, the +:math:`\Delta`-equivalence, which respects as much as possible the names +given by the users. He also designed with Pierre Letouzey a new, +convenient operator ``<+`` for nesting functor application that +provides a light notation for inheriting the properties of cascading +modules. + +The new tactic nsatz is due to Loïc Pottier. It works by computing +Gröbner bases. Regarding the existing tactics, various improvements have +been done by Matthieu Sozeau, Hugo Herbelin and Pierre Letouzey. + +Matthieu Sozeau extended and refined the typeclasses and Program +features (the Russell language). Pierre Letouzey maintained and improved +the extraction mechanism. Bruno Barras and Élie Soubiran maintained the +Coq checker, Julien Forest maintained the Function mechanism for +reasoning over recursively defined functions. Matthieu Sozeau, Hugo +Herbelin and Jean-Marc Notin maintained coqdoc. Frédéric Besson +maintained the Micromega platform for deciding systems of inequalities. +Pierre Courtieu maintained the support for the Proof General Emacs +interface. Claude Marché maintained the plugin for calling external +provers (dp). Yves Bertot made some improvements to the libraries of +lists and integers. Matthias Puech improved the search functions. +Guillaume Melquiond usefully contributed here and there. Yann +Régis-Gianas grounded the support for Unicode on a more standard and +more robust basis. + +Though invisible from outside, Arnaud Spiwack improved the general +process of management of existential variables. Pierre Letouzey and +Stéphane Glondu improved the compilation scheme of the |Coq| archive. +Vincent Gross provided support to |CoqIDE|. Jean-Marc Notin provided +support for benchmarking and archiving. + +Many users helped by reporting problems, providing patches, suggesting +improvements or making useful comments, either on the bug tracker or on +the Coq-Club mailing list. This includes but not exhaustively Cédric +Auger, Arthur Charguéraud, François Garillot, Georges Gonthier, Robin +Green, Stéphane Lescuyer, Eelis van der Weegen, ... + +Though not directly related to the implementation, special thanks are +going to Yves Bertot, Pierre Castéran, Adam Chlipala, and Benjamin +Pierce for the excellent teaching materials they provided. + +| Paris, April 2010 +| Hugo Herbelin +| + +Details of changes +~~~~~~~~~~~~~~~~~~ + +Rewriting tactics + +- Tactic "rewrite" now supports rewriting on ad hoc equalities such as eq_true. +- "Hint Rewrite" now checks that the lemma looks like an equation. +- New tactic "etransitivity". +- Support for heterogeneous equality (JMeq) in "injection" and "discriminate". +- Tactic "subst" now supports heterogeneous equality and equality + proofs that are dependent (use "simple subst" for preserving compatibility). +- Added support for Leibniz-rewriting of dependent hypotheses. +- Renamed "Morphism" into "Proper" and "respect" into "proper_prf" + (possible source of incompatibility). A partial fix is to define + "Notation Morphism R f := (Proper (R%signature) f)." +- New tactic variants "rewrite* by" and "autorewrite*" that rewrite + respectively the first and all matches whose side-conditions are + solved. +- "Require Import Setoid" does not export all of "Morphisms" and + "RelationClasses" anymore (possible source of incompatibility, fixed + by importing "Morphisms" too). +- Support added for using Chung-Kil Hur's Heq library for rewriting over + heterogeneous equality (courtesy of the library's author). +- Tactic "replace" supports matching terms with holes. + +Automation tactics + +- Tactic ``intuition`` now preserves inner ``iff`` and ``not`` (exceptional + source of incompatibilities solvable by redefining ``intuition`` as + ``unfold iff, not in *; intuition``, or, for iff only, by using + ``Set Intuition Iff Unfolding``.) +- Tactic ``tauto`` now proves classical tautologies as soon as classical logic + (i.e. library ``Classical_Prop`` or ``Classical``) is loaded. +- Tactic ``gappa`` has been removed from the Dp plugin. +- Tactic ``firstorder`` now supports the combination of its ``using`` and + ``with`` options. +- New ``Hint Resolve ->`` (or ``<-``) for declaring iff's as oriented + hints (wish #2104). +- An inductive type as argument of the ``using`` option of ``auto`` / ``eauto`` / ``firstorder`` + is interpreted as using the collection of its constructors. +- New decision tactic "nsatz" to prove polynomial equations + by computation of Groebner bases. + +Other tactics + +- Tactic "discriminate" now performs intros before trying to discriminate an + hypothesis of the goal (previously it applied intro only if the goal + had the form t1<>t2) (exceptional source of incompatibilities - former + behavior can be obtained by "Unset Discriminate Introduction"). +- Tactic "quote" now supports quotation of arbitrary terms (not just the + goal). +- Tactic "idtac" now displays its "list" arguments. +- New introduction patterns "*" for introducing the next block of dependent + variables and "**" for introducing all quantified variables and hypotheses. +- Pattern Unification for existential variables activated in tactics and + new option "Unset Tactic Evars Pattern Unification" to deactivate it. +- Resolution of canonical structure is now part of the tactic's unification + algorithm. +- New tactic "decide lemma with hyp" for rewriting decidability lemmas + when one knows which side is true. +- Improved support of dependent goals over objects in dependent types for + "destruct" (rare source of incompatibility that can be avoided by unsetting + option "Dependent Propositions Elimination"). +- Tactic "exists", "eexists", "destruct" and "edestruct" supports iteration + using comma-separated arguments. +- Tactic names "case" and "elim" now support clauses "as" and "in" and become + then synonymous of "destruct" and "induction" respectively. +- A new tactic name "exfalso" for the use of 'ex-falso quodlibet' principle. + This tactic is simply a shortcut for "elimtype False". +- Made quantified hypotheses get the name they would have if introduced in + the context (possible but rare source of incompatibilities). +- When applying a component of a conjunctive lemma, "apply in" (and + sequences of "apply in") now leave the side conditions of the lemmas + uniformly after the main goal (possible source of rare incompatibilities). +- In "simpl c" and "change c with d", c can be a pattern. +- Tactic "revert" now preserves let-in's making it the exact inverse of + "intro". +- New tactics "clear dependent H" and "revert dependent H" that + clears (resp. reverts) H and all the hypotheses that depend on H. +- Ltac's pattern-matching now supports matching metavariables that + depend on variables bound upwards in the pattern. + +Tactic definitions + +- Ltac definitions support Local option for non-export outside modules. +- Support for parsing non-empty lists with separators in tactic notations. +- New command "Locate Ltac" to get the full name of an Ltac definition. + +Notations + +- Record syntax ``{|x=...; y=...|}`` now works inside patterns too. +- Abbreviations from non-imported module now invisible at printing time. +- Abbreviations now use implicit arguments and arguments scopes for printing. +- Abbreviations to pure names now strictly behave like the name they refer to + (make redirections of qualified names easier). +- Abbreviations for applied constant now propagate the implicit arguments + and arguments scope of the underlying reference (possible source of + incompatibilities generally solvable by changing such abbreviations from + e.g. ``Notation foo' := (foo x)`` to ``Notation foo' y := (foo x (y:=y))``). +- The "where" clause now supports multiple notations per defined object. +- Recursive notations automatically expand one step on the left for better + factorization; recursion notations inner separators now ensured being tokens. +- Added "Reserved Infix" as a specific shortcut of the corresponding + "Reserved Notation". +- Open/Close Scope command supports Global option in sections. + +Specification language + +- New support for local binders in the syntax of Record/Structure fields. +- Fixpoint/CoFixpoint now support building part or all of bodies using tactics. +- Binders given before ":" in lemmas and in definitions built by tactics are + now automatically introduced (possible source of incompatibility that can + be resolved by invoking "Unset Automatic Introduction"). +- New support for multiple implicit arguments signatures per reference. + +Module system + +- Include Type is now deprecated since Include now accept both modules and + module types. +- Declare ML Module supports Local option. +- The sharing between non-logical object and the management of the + name-space has been improved by the new "Delta-equivalence" on + qualified name. +- The include operator has been extended to high-order structures +- Sequences of Include can be abbreviated via new syntax "<+". +- A module (or module type) can be given several "<:" signatures. +- Interactive proofs are now permitted in module type. Functors can hence + be declared as Module Type and be used later to type themselves. +- A functor application can be prefixed by a "!" to make it ignore any + "Inline" annotation in the type of its argument(s) (for examples of + use of the new features, see libraries Structures and Numbers). +- Coercions are now active only when modules are imported (use "Set Automatic + Coercions Import" to get the behavior of the previous versions of Coq). + +Extraction + +- When using (Recursive) Extraction Library, the filenames are directly the + Coq ones with new appropriate extensions : we do not force anymore + uncapital first letters for Ocaml and capital ones for Haskell. +- The extraction now tries harder to avoid code transformations that can be + dangerous for the complexity. In particular many eta-expansions at the top + of functions body are now avoided, clever partial applications will likely + be preserved, let-ins are almost always kept, etc. +- In the same spirit, auto-inlining is now disabled by default, except for + induction principles, since this feature was producing more frequently + weird code than clear gain. The previous behavior can be restored via + "Set Extraction AutoInline". +- Unicode characters in identifiers are now transformed into ascii strings + that are legal in Ocaml and other languages. +- Harsh support of module extraction to Haskell and Scheme: module hierarchy + is flattened, module abbreviations and functor applications are expanded, + module types and unapplied functors are discarded. +- Less unsupported situations when extracting modules to Ocaml. In particular + module parameters might be alpha-renamed if a name clash is detected. +- Extract Inductive is now possible toward non-inductive types (e.g. nat => int) +- Extraction Implicit: this new experimental command allows to mark + some arguments of a function or constructor for removed during + extraction, even if these arguments don't fit the usual elimination + principles of extraction, for instance the length n of a vector. +- Files ExtrOcaml*.v in plugins/extraction try to provide a library of common + extraction commands: mapping of basics types toward Ocaml's counterparts, + conversions from/to int and big_int, or even complete mapping of nat,Z,N + to int or big_int, or mapping of ascii to char and string to char list + (in this case recognition of ascii constants is hard-wired in the extraction). + +Program + +- Streamlined definitions using well-founded recursion and measures so + that they can work on any subset of the arguments directly (uses currying). +- Try to automatically clear structural fixpoint prototypes in + obligations to avoid issues with opacity. +- Use return type clause inference in pattern-matching as in the standard + typing algorithm. +- Support [Local Obligation Tactic] and [Next Obligation with tactic]. +- Use [Show Obligation Tactic] to print the current default tactic. +- [fst] and [snd] have maximal implicit arguments in Program now (possible + source of incompatibility). + +Type classes + +- Declaring axiomatic type class instances in Module Type should be now + done via new command "Declare Instance", while the syntax "Instance" + now always provides a concrete instance, both in and out of Module Type. +- Use [Existing Class foo] to declare foo as a class a posteriori. + [foo] can be an inductive type or a constant definition. No + projections or instances are defined. +- Various bug fixes and improvements: support for defined fields, + anonymous instances, declarations giving terms, better handling of + sections and [Context]. + +Vernacular commands + +- New command "Timeout <n> <command>." interprets a command and a timeout + interrupts the interpretation after <n> seconds. +- New command "Compute <expr>." is a shortcut for "Eval vm_compute in <expr>". +- New command "Fail <command>." interprets a command and is successful iff + the command fails on an error (but not an anomaly). Handy for tests and + illustration of wrong commands. +- Most commands referring to constant (e.g. Print or About) now support + referring to the constant by a notation string. +- New option "Boolean Equality Schemes" to make generation of boolean + equality automatic for datatypes (together with option "Decidable + Equality Schemes", this replaces deprecated option "Equality Scheme"). +- Made support for automatic generation of case analysis schemes available + to user (governed by option "Set Case Analysis Schemes"). +- New command :n:`{? Global } Generalizable [All|No] [Variable|Variables] {* @ident}` to + declare which identifiers are generalizable in `` `{} `` and `` `() `` binders. +- New command "Print Opaque Dependencies" to display opaque constants in + addition to all variables, parameters or axioms a theorem or + definition relies on. +- New command "Declare Reduction <id> := <conv_expr>", allowing to write + later "Eval <id> in ...". This command accepts a Local variant. +- Syntax of Implicit Type now supports more than one block of variables of + a given type. +- Command "Canonical Structure" now warns when it has no effects. +- Commands of the form "Set X" or "Unset X" now support "Local" and "Global" + prefixes. + +Library + +- Use "standard" Coq names for the properties of eq and identity + (e.g. refl_equal is now eq_refl). Support for compatibility is provided. + +- The function Compare_dec.nat_compare is now defined directly, + instead of relying on lt_eq_lt_dec. The earlier version is still + available under the name nat_compare_alt. + +- Lemmas in library Relations and Reals have been homogenized a bit. + +- The implicit argument of Logic.eq is now maximally inserted, allowing + to simply write "eq" instead of "@eq _" in morphism signatures. + +- Wrongly named lemmas (Zlt_gt_succ and Zlt_succ_gt) fixed (potential source + of incompatibilities) + +- List library: + + + Definitions of list, length and app are now in Init/Datatypes. + Support for compatibility is provided. + + Definition of Permutation is now in Sorting/Permtation.v + + Some other light revisions and extensions (possible source + of incompatibilities solvable by qualifying names accordingly). + +- In ListSet, set_map has been fixed (source of incompatibilities if used). + +- Sorting library: + + + new mergesort of worst-case complexity O(n*ln(n)) made available in + Mergesort.v; + + former notion of permutation up to setoid from Permutation.v is + deprecated and moved to PermutSetoid.v; + + heapsort from Heap.v of worst-case complexity O(n*n) is deprecated; + + new file Sorted.v for some definitions of being sorted. + +- Structure library. This new library is meant to contain generic + structures such as types with equalities or orders, either + in Module version (for now) or Type Classes (still to do): + + + DecidableType.v and OrderedType.v: initial notions for FSets/FMaps, + left for compatibility but considered as deprecated. + + Equalities.v and Orders.v: evolutions of the previous files, + with fine-grain Module architecture, many variants, use of + Equivalence and other relevant Type Classes notions. + + OrdersTac.v: a generic tactic for solving chains of (in)equalities + over variables. See {Nat,N,Z,P}OrderedType.v for concrete instances. + + GenericMinMax.v: any ordered type can be equipped with min and max. + We derived here all the generic properties of these functions. + +- MSets library: an important evolution of the FSets library. + "MSets" stands for Modular (Finite) Sets, by contrast with a forthcoming + library of Class (Finite) Sets contributed by S. Lescuyer which will be + integrated with the next release of Coq. The main features of MSets are: + + + The use of Equivalence, Proper and other Type Classes features + easing the handling of setoid equalities. + + The interfaces are now stated in iff-style. Old specifications + are now derived properties. + + The compare functions are now pure, and return a "comparison" value. + Thanks to the CompSpec inductive type, reasoning on them remains easy. + + Sets structures requiring invariants (i.e. sorted lists) are + built first as "Raw" sets (pure objects and separate proofs) and + attached with their proofs thanks to a generic functor. "Raw" sets + have now a proper interface and can be manipulated directly. + + Note: No Maps yet in MSets. The FSets library is still provided + for compatibility, but will probably be considered as deprecated in the + next release of Coq. + +- Numbers library: + + + The abstract layer (NatInt, Natural/Abstract, Integer/Abstract) has + been simplified and enhance thanks to new features of the module + system such as Include (see above). It has been extended to Euclidean + division (three flavors for integers: Trunc, Floor and Math). + + The arbitrary-large efficient numbers (BigN, BigZ, BigQ) has also + been reworked. They benefit from the abstract layer improvements + (especially for div and mod). Note that some specifications have + slightly changed (compare, div, mod, shift{r,l}). Ring/Field should + work better (true recognition of constants). + +Tools + +- Option -R now supports binding Coq root read-only. +- New coqtop/coqc option -beautify to reformat .v files (usable + e.g. to globally update notations). +- New tool beautify-archive to beautify a full archive of developments. +- New coqtop/coqc option -compat X.Y to simulate the general behavior + of previous versions of Coq (provides e.g. support for 8.2 compatibility). + +Coqdoc + +- List have been revamped. List depth and scope is now determined by + an "offside" whitespace rule. +- Text may be italicized by placing it in _underscores_. +- The "--index <string>" flag changes the filename of the index. +- The "--toc-depth <int>" flag limits the depth of headers which are + included in the table of contents. +- The "--lib-name <string>" flag prints "<string> Foo" instead of + "Library Foo" where library titles are called for. The + "--no-lib-name" flag eliminates the extra title. +- New option "--parse-comments" to allow parsing of regular ``(* *)`` + comments. +- New option "--plain-comments" to disable interpretation inside comments. +- New option "--interpolate" to try and typeset identifiers in Coq escapings + using the available globalization information. +- New option "--external url root" to refer to external libraries. +- Links to section variables and notations now supported. + +Internal infrastructure + +- To avoid confusion with the repository of user's contributions, + the subdirectory "contrib" has been renamed into "plugins". + On platforms supporting ocaml native dynlink, code located there + is built as loadable plugins for coqtop. +- An experimental build mechanism via ocamlbuild is provided. + From the top of the archive, run ./configure as usual, and + then ./build. Feedback about this build mechanism is most welcome. + Compiling Coq on platforms such as Windows might be simpler + this way, but this remains to be tested. +- The Makefile system has been simplified and factorized with + the ocamlbuild system. In particular "make" takes advantage + of .mllib files for building .cma/.cmxa. The .vo files to + compile are now listed in several vo.itarget files. + +Version 8.2 +----------- + +Summary of changes +~~~~~~~~~~~~~~~~~~ + +Coq version 8.2 adds new features, new libraries and improves on many +various aspects. + +Regarding the language of |Coq|, the main novelty is the introduction by +Matthieu Sozeau of a package of commands providing Haskell-style typeclasses. +Typeclasses, which come with a few convenient features such as +type-based resolution of implicit arguments, play a new landmark role +in the architecture of |Coq| with respect to automation. For +instance, thanks to typeclass support, Matthieu Sozeau could +implement a new resolution-based version of the tactics dedicated to +rewriting on arbitrary transitive relations. + +Another major improvement of |Coq| 8.2 is the evolution of the arithmetic +libraries and of the tools associated to them. Benjamin Grégoire and +Laurent Théry contributed a modular library for building arbitrarily +large integers from bounded integers while Evgeny Makarov contributed a +modular library of abstract natural and integer arithmetic together +with a few convenient tactics. On his side, Pierre Letouzey made +numerous extensions to the arithmetic libraries on :math:`\mathbb{Z}` +and :math:`\mathbb{Q}`, including extra support for automation in +presence of various number-theory concepts. + +Frédéric Besson contributed a reflective tactic based on Krivine-Stengle +Positivstellensatz (the easy way) for validating provability of systems +of inequalities. The platform is flexible enough to support the +validation of any algorithm able to produce a “certificate” for the +Positivstellensatz and this covers the case of Fourier-Motzkin (for +linear systems in :math:`\mathbb{Q}` and :math:`\mathbb{R}`), +Fourier-Motzkin with cutting planes (for linear systems in +:math:`\mathbb{Z}`) and sum-of-squares (for non-linear systems). Evgeny +Makarov made the platform generic over arbitrary ordered rings. + +Arnaud Spiwack developed a library of 31-bits machine integers and, +relying on Benjamin Grégoire and Laurent Théry’s library, delivered a +library of unbounded integers in base :math:`2^{31}`. As importantly, he +developed a notion of “retro-knowledge” so as to safely extend the +kernel-located bytecode-based efficient evaluation algorithm of |Coq| +version 8.1 to use 31-bits machine arithmetic for efficiently computing +with the library of integers he developed. + +Beside the libraries, various improvements were contributed to provide a more +comfortable end-user language and more expressive tactic language. Hugo +Herbelin and Matthieu Sozeau improved the pattern matching compilation +algorithm (detection of impossible clauses in pattern matching, +automatic inference of the return type). Hugo Herbelin, Pierre Letouzey +and Matthieu Sozeau contributed various new convenient syntactic +constructs and new tactics or tactic features: more inference of +redundant information, better unification, better support for proof or +definition by fixpoint, more expressive rewriting tactics, better +support for meta-variables, more convenient notations... + +Élie Soubiran improved the module system, adding new features (such as +an “include” command) and making it more flexible and more general. He +and Pierre Letouzey improved the support for modules in the extraction +mechanism. + +Matthieu Sozeau extended the Russell language, ending in an convenient +way to write programs of given specifications, Pierre Corbineau extended +the Mathematical Proof Language and the automation tools that +accompany it, Pierre Letouzey supervised and extended various parts of the +standard library, Stéphane Glondu contributed a few tactics and +improvements, Jean-Marc Notin provided help in debugging, general +maintenance and coqdoc support, Vincent Siles contributed extensions of +the Scheme command and of injection. + +Bruno Barras implemented the ``coqchk`` tool: this is a stand-alone +type checker that can be used to certify .vo files. Especially, as this +verifier runs in a separate process, it is granted not to be “hijacked” +by virtually malicious extensions added to |Coq|. + +Yves Bertot, Jean-Christophe Filliâtre, Pierre Courtieu and Julien +Forest acted as maintainers of features they implemented in previous +versions of |Coq|. + +Julien Narboux contributed to |CoqIDE|. Nicolas Tabareau made the +adaptation of the interface of the old “setoid rewrite” tactic to the +new version. Lionel Mamane worked on the interaction between |Coq| and its +external interfaces. With Samuel Mimram, he also helped making |Coq| +compatible with recent software tools. Russell O’Connor, Cezary +Kaliszyk, Milad Niqui contributed to improve the libraries of integers, +rational, and real numbers. We also thank many users and partners for +suggestions and feedback, in particular Pierre Castéran and Arthur +Charguéraud, the INRIA Marelle team, Georges Gonthier and the +INRIA-Microsoft Mathematical Components team, the Foundations group at +Radboud university in Nijmegen, reporters of bugs and participants to +the Coq-Club mailing list. + +| Palaiseau, June 2008 +| Hugo Herbelin +| + +Details of changes +~~~~~~~~~~~~~~~~~~ + +Language + +- If a fixpoint is not written with an explicit { struct ... }, then + all arguments are tried successively (from left to right) until one is + found that satisfies the structural decreasing condition. +- New experimental typeclass system giving ad-hoc polymorphism and + overloading based on dependent records and implicit arguments. +- New syntax "let 'pat := b in c" for let-binding using irrefutable patterns. +- New syntax "forall {A}, T" for specifying maximally inserted implicit + arguments in terms. +- Sort of Record/Structure, Inductive and CoInductive defaults to Type + if omitted. +- (Co)Inductive types can be defined as records + (e.g. "CoInductive stream := { hd : nat; tl : stream }.") +- New syntax "Theorem id1:t1 ... with idn:tn" for proving mutually dependent + statements. +- Support for sort-polymorphism on constants denoting inductive types. +- Several evolutions of the module system (handling of module aliases, + functorial module types, an Include feature, etc). +- Prop now a subtype of Set (predicative and impredicative forms). +- Recursive inductive types in Prop with a single constructor of which + all arguments are in Prop is now considered to be a singleton + type. It consequently supports all eliminations to Prop, Set and Type. + As a consequence, Acc_rect has now a more direct proof [possible source + of easily fixed incompatibility in case of manual definition of a recursor + in a recursive singleton inductive type]. + +Vernacular commands + +- Added option Global to "Arguments Scope" for section surviving. +- Added option "Unset Elimination Schemes" to deactivate the automatic + generation of elimination schemes. +- Modification of the Scheme command so you can ask for the name to be + automatically computed (e.g. Scheme Induction for nat Sort Set). +- New command "Combined Scheme" to build combined mutual induction + principles from existing mutual induction principles. +- New command "Scheme Equality" to build a decidable (boolean) equality + for simple inductive datatypes and a decision property over this equality + (e.g. Scheme Equality for nat). +- Added option "Set Equality Scheme" to make automatic the declaration + of the boolean equality when possible. +- Source of universe inconsistencies now printed when option + "Set Printing Universes" is activated. +- New option "Set Printing Existential Instances" for making the display of + existential variable instances explicit. +- Support for option "[id1 ... idn]", and "-[id1 ... idn]", for the + "compute"/"cbv" reduction strategy, respectively meaning reduce only, or + everything but, the constants id1 ... idn. "lazy" alone or followed by + "[id1 ... idn]", and "-[id1 ... idn]" also supported, meaning apply + all of beta-iota-zeta-delta, possibly restricting delta. +- New command "Strategy" to control the expansion of constants during + conversion tests. It generalizes commands Opaque and Transparent by + introducing a range of levels. Lower levels are assigned to constants + that should be expanded first. +- New options Global and Local to Opaque and Transparent. +- New command "Print Assumptions" to display all variables, parameters + or axioms a theorem or definition relies on. +- "Add Rec LoadPath" now provides references to libraries using partially + qualified names (this holds also for coqtop/coqc option -R). +- SearchAbout supports negated search criteria, reference to logical objects + by their notation, and more generally search of subterms. +- "Declare ML Module" now allows to import .cmxs files when Coq is + compiled in native code with a version of OCaml that supports native + Dynlink (>= 3.11). +- Specific sort constraints on Record now taken into account. +- "Print LoadPath" supports a path argument to filter the display. + +Libraries + +- Several parts of the libraries are now in Type, in particular FSets, + SetoidList, ListSet, Sorting, Zmisc. This may induce a few + incompatibilities. In case of trouble while fixing existing development, + it may help to simply declare Set as an alias for Type (see file + SetIsType). + +- New arithmetical library in theories/Numbers. It contains: + + * an abstract modular development of natural and integer arithmetics + in Numbers/Natural/Abstract and Numbers/Integer/Abstract + * an implementation of efficient computational bounded and unbounded + integers that can be mapped to processor native arithmetics. + See Numbers/Cyclic/Int31 for 31-bit integers and Numbers/Natural/BigN + for unbounded natural numbers and Numbers/Integer/BigZ for unbounded + integers. + * some proofs that both older libraries Arith, ZArith and NArith and + newer BigN and BigZ implement the abstract modular development. + This allows in particular BigN and BigZ to already come with a + large database of basic lemmas and some generic tactics (ring), + + This library has still an experimental status, as well as the + processor-acceleration mechanism, but both its abstract and its + concrete parts are already quite usable and could challenge the use + of nat, N and Z in actual developments. Moreover, an extension of + this framework to rational numbers is ongoing, and an efficient + Q structure is already provided (see Numbers/Rational/BigQ), but + this part is currently incomplete (no abstract layer and generic + lemmas). + +- Many changes in FSets/FMaps. In practice, compatibility with earlier + version should be fairly good, but some adaptations may be required. + + * Interfaces of unordered ("weak") and ordered sets have been factorized + thanks to new features of Coq modules (in particular Include), see + FSetInterface. Same for maps. Hints in these interfaces have been + reworked (they are now placed in a "set" database). + * To allow full subtyping between weak and ordered sets, a field + "eq_dec" has been added to OrderedType. The old version of OrderedType + is now called MiniOrderedType and functor MOT_to_OT allow to + convert to the new version. The interfaces and implementations + of sets now contain also such a "eq_dec" field. + * FSetDecide, contributed by Aaron Bohannon, contains a decision + procedure allowing to solve basic set-related goals (for instance, + is a point in a particular set ?). See FSetProperties for examples. + * Functors of properties have been improved, especially the ones about + maps, that now propose some induction principles. Some properties + of fold need less hypothesis. + * More uniformity in implementations of sets and maps: they all use + implicit arguments, and no longer export unnecessary scopes (see + bug #1347) + * Internal parts of the implementations based on AVL have evolved a + lot. The main files FSetAVL and FMapAVL are now much more + lightweight now. In particular, minor changes in some functions + has allowed to fully separate the proofs of operational + correctness from the proofs of well-balancing: well-balancing is + critical for efficiency, but not anymore for proving that these + trees implement our interfaces, hence we have moved these proofs + into appendix files FSetFullAVL and FMapFullAVL. Moreover, a few + functions like union and compare have been modified in order to be + structural yet efficient. The appendix files also contains + alternative versions of these few functions, much closer to the + initial Ocaml code and written via the Function framework. + +- Library IntMap, subsumed by FSets/FMaps, has been removed from + Coq Standard Library and moved into a user contribution Cachan/IntMap + +- Better computational behavior of some constants (eq_nat_dec and + le_lt_dec more efficient, Z_lt_le_dec and Positive_as_OT.compare + transparent, ...) (exceptional source of incompatibilities). + +- Boolean operators moved from module Bool to module Datatypes (may need + to rename qualified references in script and force notations || and && + to be at levels 50 and 40 respectively). + +- The constructors xI and xO of type positive now have postfix notations + "~1" and "~0", allowing to write numbers in binary form easily, for instance + 6 is 1~1~0 and 4*p is p~0~0 (see BinPos.v). + +- Improvements to NArith (Nminus, Nmin, Nmax), and to QArith (in particular + a better power function). + +- Changes in ZArith: several additional lemmas (used in theories/Numbers), + especially in Zdiv, Znumtheory, Zpower. Moreover, many results in + Zdiv have been generalized: the divisor may simply be non-null + instead of strictly positive (see lemmas with name ending by + "_full"). An alternative file ZOdiv proposes a different behavior + (the one of Ocaml) when dividing by negative numbers. + +- Changes in Arith: EqNat and Wf_nat now exported from Arith, some + constructions on nat that were outside Arith are now in (e.g. iter_nat). + +- In SetoidList, eqlistA now expresses that two lists have similar elements + at the same position, while the predicate previously called eqlistA + is now equivlistA (this one only states that the lists contain the same + elements, nothing more). + +- Changes in Reals: + + * Most statement in "sigT" (including the + completeness axiom) are now in "sig" (in case of incompatibility, + use proj1_sig instead of projT1, sig instead of sigT, etc). + * More uniform naming scheme (identifiers in French moved to English, + consistent use of 0 -- zero -- instead of O -- letter O --, etc). + * Lemma on prod_f_SO is now on prod_f_R0. + * Useless hypothesis of ln_exists1 dropped. + * New Rlogic.v states a few logical properties about R axioms. + * RIneq.v extended and made cleaner. + +- Slight restructuration of the Logic library regarding choice and classical + logic. Addition of files providing intuitionistic axiomatizations of + descriptions: Epsilon.v, Description.v and IndefiniteDescription.v. + +- Definition of pred and minus made compatible with the structural + decreasing criterion for use in fixpoints. + +- Files Relations/Rstar.v and Relations/Newman.v moved out to the user + contribution repository (contribution CoC_History). New lemmas about + transitive closure added and some bound variables renamed (exceptional + risk of incompatibilities). + +- Syntax for binders in terms (e.g. for "exists") supports anonymous names. + +Notations, coercions, implicit arguments and type inference + +- More automation in the inference of the return clause of dependent + pattern-matching problems. +- Experimental allowance for omission of the clauses easily detectable as + impossible in pattern-matching problems. +- Improved inference of implicit arguments. +- New options "Set Maximal Implicit Insertion", "Set Reversible Pattern + Implicit", "Set Strongly Strict Implicit" and "Set Printing Implicit + Defensive" for controlling inference and use of implicit arguments. +- New modifier in "Implicit Arguments" to force an implicit argument to + be maximally inserted. +- New modifier of "Implicit Arguments" to enrich the set of implicit arguments. +- New options Global and Local to "Implicit Arguments" for section + surviving or non export outside module. +- Level "constr" moved from 9 to 8. +- Structure/Record now printed as Record (unless option Printing All is set). +- Support for parametric notations defining constants. +- Insertion of coercions below product types refrains to unfold + constants (possible source of incompatibility). +- New support for fix/cofix in notations. + +Tactic Language + +- Second-order pattern-matching now working in Ltac "match" clauses + (syntax for second-order unification variable is "@?X"). +- Support for matching on let bindings in match context using syntax + "H := body" or "H := body : type". +- Ltac accepts integer arguments (syntax is "ltac:nnn" for nnn an integer). +- The general sequence tactical "expr_0 ; [ expr_1 | ... | expr_n ]" + is extended so that at most one expr_i may have the form "expr .." + or just "..". Also, n can be different from the number of subgoals + generated by expr_0. In this case, the value of expr (or idtac in + case of just "..") is applied to the intermediate subgoals to make + the number of tactics equal to the number of subgoals. +- A name used as the name of the parameter of a lemma (like f in + "apply f_equal with (f:=t)") is now interpreted as a ltac variable + if such a variable exists (this is a possible source of + incompatibility and it can be fixed by renaming the variables of a + ltac function into names that do not clash with the lemmas + parameter names used in the tactic). +- New syntax "Ltac tac ::= ..." to rebind a tactic to a new expression. +- "let rec ... in ... " now supported for expressions without explicit + parameters; interpretation is lazy to the contrary of "let ... in ..."; + hence, the "rec" keyword can be used to turn the argument of a + "let ... in ..." into a lazy one. +- Patterns for hypotheses types in "match goal" are now interpreted in + type_scope. +- A bound variable whose name is not used elsewhere now serves as + metavariable in "match" and it gets instantiated by an identifier + (allow e.g. to extract the name of a statement like "exists x, P x"). +- New printing of Ltac call trace for better debugging. + +Tactics + +- New tactics "apply -> term", "apply <- term", "apply -> term in + ident", "apply <- term in ident" for applying equivalences (iff). + +- Slight improvement of the hnf and simpl tactics when applied on + expressions with explicit occurrences of match or fix. + +- New tactics "eapply in", "erewrite", "erewrite in". + +- New tactics "ediscriminate", "einjection", "esimplify_eq". + +- Tactics "discriminate", "injection", "simplify_eq" now support any + term as argument. Clause "with" is also supported. + +- Unfoldable references can be given by notation's string rather than by name + in unfold. + +- The "with" arguments are now typed using informations from the current goal: + allows support for coercions and more inference of implicit arguments. + +- Application of "f_equal"-style lemmas works better. + +- Tactics elim, case, destruct and induction now support variants eelim, + ecase, edestruct and einduction. + +- Tactics destruct and induction now support the "with" option and the + "in" clause option. If the option "in" is used, an equality is added + to remember the term to which the induction or case analysis applied + (possible source of parsing incompatibilities when destruct or induction is + part of a let-in expression in Ltac; extra parentheses are then required). + +- New support for "as" clause in tactics "apply in" and "eapply in". + +- Some new intro patterns: + + * intro pattern "?A" genererates a fresh name based on A. + Caveat about a slight loss of compatibility: + Some intro patterns don't need space between them. In particular + intros ?a?b used to be legal and equivalent to intros ? a ? b. Now it + is still legal but equivalent to intros ?a ?b. + * intro pattern "(A & ... & Y & Z)" synonym to "(A,....,(Y,Z)))))" + for right-associative constructs like /\ or exists. + +- Several syntax extensions concerning "rewrite": + + * "rewrite A,B,C" can be used to rewrite A, then B, then C. These rewrites + occur only on the first subgoal: in particular, side-conditions of the + "rewrite A" are not concerned by the "rewrite B,C". + * "rewrite A by tac" allows to apply tac on all side-conditions generated by + the "rewrite A". + * "rewrite A at n" allows to select occurrences to rewrite: rewrite only + happen at the n-th exact occurrence of the first successful matching of + A in the goal. + * "rewrite 3 A" or "rewrite 3!A" is equivalent to "rewrite A,A,A". + * "rewrite !A" means rewriting A as long as possible (and at least once). + * "rewrite 3?A" means rewriting A at most three times. + * "rewrite ?A" means rewriting A as long as possible (possibly never). + * many of the above extensions can be combined with each other. + +- Introduction patterns better respect the structure of context in presence of + missing or extra names in nested disjunction-conjunction patterns [possible + source of rare incompatibilities]. + +- New syntax "rename a into b, c into d" for "rename a into b; rename c into d" + +- New tactics "dependent induction/destruction H [ generalizing id_1 .. id_n ]" + to do induction-inversion on instantiated inductive families à la BasicElim. + +- Tactics "apply" and "apply in" now able to reason modulo unfolding of + constants (possible source of incompatibility in situations where apply + may fail, e.g. as argument of a try or a repeat and in a ltac function); + versions that do not unfold are renamed into "simple apply" and + "simple apply in" (usable for compatibility or for automation). + +- Tactics "apply" and "apply in" now able to traverse conjunctions and to + select the first matching lemma among the components of the conjunction; + tactic "apply" also able to apply lemmas of conclusion an empty type. + +- Tactic "apply" now supports application of several lemmas in a row. + +- Tactics "set" and "pose" can set functions using notation "(f x1..xn := c)". + +- New tactic "instantiate" (without argument). + +- Tactic firstorder "with" and "using" options have their meaning swapped for + consistency with auto/eauto (source of incompatibility). + +- Tactic "generalize" now supports "at" options to specify occurrences + and "as" options to name the quantified hypotheses. + +- New tactic "specialize H with a" or "specialize (H a)" allows to transform + in-place a universally-quantified hypothesis (H : forall x, T x) into its + instantiated form (H : T a). Nota: "specialize" was in fact there in earlier + versions of Coq, but was undocumented, and had a slightly different behavior. + +- New tactic "contradict H" can be used to solve any kind of goal as long as + the user can provide afterwards a proof of the negation of the hypothesis H. + If H is already a negation, say ~T, then a proof of T is asked. + If the current goal is a negation, say ~U, then U is saved in H afterwards, + hence this new tactic "contradict" extends earlier tactic "swap", which is + now obsolete. + +- Tactics f_equal is now done in ML instead of Ltac: it now works on any + equality of functions, regardless of the arity of the function. + +- New options "before id", "at top", "at bottom" for tactics "move"/"intro". + +- Some more debug of reflexive omega (``romega``), and internal clarifications. + Moreover, romega now has a variant ``romega with *`` that can be also used + on non-Z goals (nat, N, positive) via a call to a translation tactic named + zify (its purpose is to Z-ify your goal...). This zify may also be used + independently of romega. + +- Tactic "remember" now supports an "in" clause to remember only selected + occurrences of a term. + +- Tactic "pose proof" supports name overwriting in case of specialization of an + hypothesis. + +- Semi-decision tactic "jp" for first-order intuitionistic logic moved to user + contributions (subsumed by "firstorder"). + +Program + +- Moved useful tactics in theories/Program and documented them. +- Add Program.Basics which contains standard definitions for functional + programming (id, apply, flip...) +- More robust obligation handling, dependent pattern-matching and + well-founded definitions. +- New syntax " dest term as pat in term " for destructing objects using + an irrefutable pattern while keeping equalities (use this instead of + "let" in Programs). +- Program CoFixpoint is accepted, Program Fixpoint uses the new way to infer + which argument decreases structurally. +- Program Lemma, Axiom etc... now permit to have obligations in the statement + iff they can be automatically solved by the default tactic. +- Renamed "Obligations Tactic" command to "Obligation Tactic". +- New command "Preterm [ of id ]" to see the actual term fed to Coq for + debugging purposes. +- New option "Transparent Obligations" to control the declaration of + obligations as transparent or opaque. All obligations are now transparent + by default, otherwise the system declares them opaque if possible. +- Changed the notations "left" and "right" to "in_left" and "in_right" to hide + the proofs in standard disjunctions, to avoid breaking existing scripts when + importing Program. Also, put them in program_scope. + +Type Classes + +- New "Class", "Instance" and "Program Instance" commands to define + classes and instances documented in the reference manual. +- New binding construct " [ Class_1 param_1 .. param_n, Class_2 ... ] " + for binding type classes, usable everywhere. +- New command " Print Classes " and " Print Instances some_class " to + print tables for typeclasses. +- New default eauto hint database "typeclass_instances" used by the default + typeclass instance search tactic. +- New theories directory "theories/Classes" for standard typeclasses + declarations. Module Classes.RelationClasses is a typeclass port of + Relation_Definitions plus a generic development of algebra on + n-ary heterogeneous predicates. + +Setoid rewriting + +- Complete (and still experimental) rewrite of the tactic + based on typeclasses. The old interface and semantics are + almost entirely respected, except: + + + Import Setoid is now mandatory to be able to call setoid_replace + and declare morphisms. + + + "-->", "++>" and "==>" are now right associative notations + declared at level 55 in scope signature_scope. + Their introduction may break existing scripts that defined + them as notations with different levels. + + + One needs to use [Typeclasses unfold [cst]] if [cst] is used + as an abbreviation hiding products in types of morphisms, + e.g. if ones redefines [relation] and declares morphisms + whose type mentions [relation]. + + + The [setoid_rewrite]'s semantics change when rewriting with + a lemma: it can rewrite two different instantiations of the lemma + at once. Use [setoid_rewrite H at 1] for (almost) the usual semantics. + [setoid_rewrite] will also try to rewrite under binders now, and can + succeed on different terms than before. In particular, it will unify under + let-bound variables. When called through [rewrite], the semantics are + unchanged though. + + + [Add Morphism term : id] has different semantics when used with + parametric morphism: it will try to find a relation on the parameters + too. The behavior has also changed with respect to default relations: + the most recently declared Setoid/Relation will be used, the documentation + explains how to customize this behavior. + + + Parametric Relation and Morphism are declared differently, using the + new [Add Parametric] commands, documented in the manual. + + + Setoid_Theory is now an alias to Equivalence, scripts building objects + of type Setoid_Theory need to unfold (or "red") the definitions + of Reflexive, Symmetric and Transitive in order to get the same goals + as before. Scripts which introduced variables explicitely will not break. + + + The order of subgoals when doing [setoid_rewrite] with side-conditions + is always the same: first the new goal, then the conditions. + +- New standard library modules ``Classes.Morphisms`` declares + standard morphisms on ``refl`` / ``sym`` / ``trans`` relations. + ``Classes.Morphisms_Prop`` declares morphisms on propositional + connectives and ``Classes.Morphisms_Relations`` on generalized predicate + connectives. ``Classes.Equivalence`` declares notations and tactics + related to equivalences and ``Classes.SetoidTactics`` defines the + setoid_replace tactics and some support for the ``Add *`` interface, + notably the tactic applied automatically before each ``Add Morphism`` + proof. + +- User-defined subrelations are supported, as well as higher-order morphisms + and rewriting under binders. The tactic is also extensible entirely in Ltac. + The documentation has been updated to cover these features. + +- [setoid_rewrite] and [rewrite] now support the [at] modifier to select + occurrences to rewrite, and both use the [setoid_rewrite] code, even when + rewriting with leibniz equality if occurrences are specified. + +Extraction + +- Improved behavior of the Caml extraction of modules: name clashes should + not happen anymore. + +- The command Extract Inductive has now a syntax for infix notations. This + allows in particular to map Coq lists and pairs onto Caml ones: + + + Extract Inductive list => list [ "[]" "(::)" ]. + + Extract Inductive prod => "(*)" [ "(,)" ]. + +- In pattern matchings, a default pattern "| _ -> ..." is now used whenever + possible if several branches are identical. For instance, functions + corresponding to decidability of equalities are now linear instead of + quadratic. + +- A new instruction Extraction Blacklist id1 .. idn allows to prevent filename + conflits with existing code, for instance when extracting module List + to Ocaml. + +CoqIDE + +- CoqIDE font defaults to monospace so as indentation to be meaningful. +- CoqIDE supports nested goals and any other kind of declaration in the middle + of a proof. +- Undoing non-tactic commands in CoqIDE works faster. +- New CoqIDE menu for activating display of various implicit informations. +- Added the possibility to choose the location of tabs in coqide: + (in Edit->Preferences->Misc) +- New Open and Save As dialogs in CoqIDE which filter ``*.v`` files. + +Tools + +- New stand-alone .vo files verifier "coqchk". +- Extended -I coqtop/coqc option to specify a logical dir: "-I dir -as coqdir". +- New coqtop/coqc option -exclude-dir to exclude subdirs for option -R. +- The binary "parser" has been renamed to "coq-parser". +- Improved coqdoc and dump of globalization information to give more + meta-information on identifiers. All categories of Coq definitions are + supported, which makes typesetting trivial in the generated documentation. + Support for hyperlinking and indexing developments in the tex output + has been implemented as well. + +Miscellaneous + +- Coq installation provides enough files so that Ocaml's extensions need not + the Coq sources to be compiled (this assumes O'Caml 3.10 and Camlp5). +- New commands "Set Whelp Server" and "Set Whelp Getter" to customize the + Whelp search tool. +- Syntax of "Test Printing Let ref" and "Test Printing If ref" changed into + "Test Printing Let for ref" and "Test Printing If for ref". +- An overhauled build system (new Makefiles); see dev/doc/build-system.txt. +- Add -browser option to configure script. +- Build a shared library for the C part of Coq, and use it by default on + non-(Windows or MacOS) systems. Bytecode executables are now pure. The + behaviour is configurable with -coqrunbyteflags, -coqtoolsbyteflags and + -custom configure options. +- Complexity tests can be skipped by setting the environment variable + COQTEST_SKIPCOMPLEXITY. + +Version 8.1 +----------- + +Summary of changes +~~~~~~~~~~~~~~~~~~ + +Coq version 8.1 adds various new functionalities. + +Benjamin Grégoire implemented an alternative algorithm to check the +convertibility of terms in the |Coq| type checker. This alternative +algorithm works by compilation to an efficient bytecode that is +interpreted in an abstract machine similar to Xavier Leroy’s ZINC +machine. Convertibility is performed by comparing the normal forms. This +alternative algorithm is specifically interesting for proofs by +reflection. More generally, it is convenient in case of intensive +computations. + +Christine Paulin implemented an extension of inductive types allowing +recursively non uniform parameters. Hugo Herbelin implemented +sort-polymorphism for inductive types (now called template polymorphism). + +Claudio Sacerdoti Coen improved the tactics for rewriting on arbitrary +compatible equivalence relations. He also generalized rewriting to +arbitrary transition systems. + +Claudio Sacerdoti Coen added new features to the module system. + +Benjamin Grégoire, Assia Mahboubi and Bruno Barras developed a new, more +efficient and more general simplification algorithm for rings and +semirings. + +Laurent Théry and Bruno Barras developed a new, significantly more +efficient simplification algorithm for fields. + +Hugo Herbelin, Pierre Letouzey, Julien Forest, Julien Narboux and +Claudio Sacerdoti Coen added new tactic features. + +Hugo Herbelin implemented matching on disjunctive patterns. + +New mechanisms made easier the communication between |Coq| and external +provers. Nicolas Ayache and Jean-Christophe Filliâtre implemented +connections with the provers cvcl, Simplify and zenon. Hugo Herbelin +implemented an experimental protocol for calling external tools from the +tactic language. + +Matthieu Sozeau developed Russell, an experimental language to specify +the behavior of programs with subtypes. + +A mechanism to automatically use some specific tactic to solve +unresolved implicit has been implemented by Hugo Herbelin. + +Laurent Théry’s contribution on strings and Pierre Letouzey and +Jean-Christophe Filliâtre’s contribution on finite maps have been +integrated to the |Coq| standard library. Pierre Letouzey developed a +library about finite sets “à la Objective Caml”. With Jean-Marc Notin, +he extended the library on lists. Pierre Letouzey’s contribution on +rational numbers has been integrated and extended. + +Pierre Corbineau extended his tactic for solving first-order statements. +He wrote a reflection-based intuitionistic tautology solver. + +Pierre Courtieu, Julien Forest and Yves Bertot added extra support to +reason on the inductive structure of recursively defined functions. + +Jean-Marc Notin significantly contributed to the general maintenance of +the system. He also took care of ``coqdoc``. + +Pierre Castéran contributed to the documentation of (co-)inductive types +and suggested improvements to the libraries. + +Pierre Corbineau implemented a declarative mathematical proof language, +usable in combination with the tactic-based style of proof. + +Finally, many users suggested improvements of the system through the +Coq-Club mailing list and bug-tracker systems, especially user groups +from INRIA Rocquencourt, Radboud University, University of Pennsylvania +and Yale University. + +| Palaiseau, July 2006 +| Hugo Herbelin +| + +Details of changes in 8.1beta +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Logic + +- Added sort-polymorphism on inductive families +- Allowance for recursively non uniform parameters in inductive types + +Syntax + +- No more support for version 7 syntax and for translation to version 8 syntax. +- In fixpoints, the { struct ... } annotation is not mandatory any more when + only one of the arguments has an inductive type +- Added disjunctive patterns in match-with patterns +- Support for primitive interpretation of string literals +- Extended support for Unicode ranges + +Vernacular commands + +- Added "Print Ltac qualid" to print a user defined tactic. +- Added "Print Rewrite HintDb" to print the content of a DB used by + autorewrite. +- Added "Print Canonical Projections". +- Added "Example" as synonym of "Definition". +- Added "Proposition" and "Corollary" as extra synonyms of "Lemma". +- New command "Whelp" to send requests to the Helm database of proofs + formalized in the Calculus of Inductive Constructions. +- Command "functional induction" has been re-implemented from the new + "Function" command. + +Ltac and tactic syntactic extensions + +- New primitive "external" for communication with tool external to Coq +- New semantics for "match t with": if a clause returns a + tactic, it is now applied to the current goal. If it fails, the next + clause or next matching subterm is tried (i.e. it behaves as "match + goal with" does). The keyword "lazymatch" can be used to delay the + evaluation of tactics occurring in matching clauses. +- Hint base names can be parametric in auto and trivial. +- Occurrence values can be parametric in unfold, pattern, etc. +- Added entry constr_may_eval for tactic extensions. +- Low-priority term printer made available in ML-written tactic extensions. +- "Tactic Notation" extended to allow notations of tacticals. + +Tactics + +- New implementation and generalization of ``setoid_*`` (``setoid_rewrite``, + ``setoid_symmetry``, ``setoid_transitivity``, ``setoid_reflexivity`` and ``autorewite``). + New syntax for declaring relations and morphisms (old syntax still working + with minor modifications, but deprecated). + +- New implementation (still experimental) of the ring tactic with a built-in + notion of coefficients and a better usage of setoids. + +- New conversion tactic "vm_compute": evaluates the goal (or an hypothesis) + with a call-by-value strategy, using the compiled version of terms. + +- When rewriting H where H is not directly a Coq equality, search first H for + a registered setoid equality before starting to reduce in H. This is unlikely + to break any script. Should this happen nonetheless, one can insert manually + some "unfold ... in H" before rewriting. + +- Fixed various bugs about (setoid) rewrite ... in ... (in particular bug #5941) + +- "rewrite ... in" now accepts a clause as place where to rewrite instead of + just a simple hypothesis name. For instance: + ``rewrite H in H1,H2 |- *`` means ``rewrite H in H1; rewrite H in H2; rewrite H`` + ``rewrite H in * |-`` will do try ``rewrite H in Hi`` for all hypothesis Hi <> H. + +- Added "dependent rewrite term" and "dependent rewrite term in hyp". + +- Added "autorewrite with ... in hyp [using ...]". + +- Tactic "replace" now accepts a "by" tactic clause. + +- Added "clear - id" to clear all hypotheses except the ones depending in id. + +- The argument of Declare Left Step and Declare Right Step is now a term + (it used to be a reference). + +- Omega now handles arbitrary precision integers. + +- Several bug fixes in Reflexive Omega (romega). + +- Idtac can now be left implicit in a [...|...] construct: for instance, + [ foo | | bar ] stands for [ foo | idtac | bar ]. + +- Fixed a "fold" bug (non critical but possible source of incompatibilities). + +- Added classical_left and classical_right which transforms ``|- A \/ B`` into + ``~B |- A`` and ``~A |- B`` respectively. + +- Added command "Declare Implicit Tactic" to set up a default tactic to be + used to solve unresolved subterms of term arguments of tactics. + +- Better support for coercions to Sortclass in tactics expecting type + arguments. + +- Tactic "assert" now accepts "as" intro patterns and "by" tactic clauses. + +- New tactic "pose proof" that generalizes "assert (id:=p)" with intro patterns. + +- New introduction pattern "?" for letting Coq choose a name. + +- Introduction patterns now support side hypotheses (e.g. intros [|] on + "(nat -> nat) -> nat" works). + +- New introduction patterns "->" and "<-" for immediate rewriting of + introduced hypotheses. + +- Introduction patterns coming after non trivial introduction patterns now + force full introduction of the first pattern (e.g. ``intros [[|] p]`` on + ``nat->nat->nat`` now behaves like ``intros [[|?] p]``) + +- Added "eassumption". + +- Added option 'using lemmas' to auto, trivial and eauto. + +- Tactic "congruence" is now complete for its intended scope (ground + equalities and inequalities with constructors). Furthermore, it + tries to equates goal and hypotheses. + +- New tactic "rtauto" solves pure propositional logic and gives a + reflective version of the available proof. + +- Numbering of "pattern", "unfold", "simpl", ... occurrences in "match + with" made consistent with the printing of the return clause after + the term to match in the "match-with" construct (use "Set Printing All" + to see hidden occurrences). + +- Generalization of induction "induction x1...xn using scheme" where + scheme is an induction principle with complex predicates (like the + ones generated by function induction). + +- Some small Ltac tactics has been added to the standard library + (file Tactics.v): + + * f_equal : instead of using the different f_equalX lemmas + * case_eq : a "case" without loss of information. An equality + stating the current situation is generated in every sub-cases. + * swap : for a negated goal ~B and a negated hypothesis H:~A, + swap H asks you to prove A from hypothesis B + * revert : revert H is generalize H; clear H. + +Extraction + +- All type parts should now disappear instead of sometimes producing _ + (for instance in Map.empty). +- Haskell extraction: types of functions are now printed, better + unsafeCoerce mechanism, both for hugs and ghc. +- Scheme extraction improved, see http://www.pps.jussieu.fr/~letouzey/scheme. +- Many bug fixes. + +Modules + +- Added "Locate Module qualid" to get the full path of a module. +- Module/Declare Module syntax made more uniform. +- Added syntactic sugar "Declare Module Export/Import" and + "Module Export/Import". +- Added syntactic sugar "Module M(Export/Import X Y: T)" and + "Module Type M(Export/Import X Y: T)" + (only for interactive definitions) +- Construct "with" generalized to module paths: + T with (Definition|Module) M1.M2....Mn.l := l'. + +Notations + +- Option "format" aware of recursive notations. +- Added insertion of spaces by default in recursive notations w/o separators. +- No more automatic printing box in case of user-provided printing "format". +- New notation "exists! x:A, P" for unique existence. +- Notations for specific numerals now compatible with generic notations of + numerals (e.g. "1" can be used to denote the unit of a group without + hiding 1%nat) + +Libraries + +- New library on String and Ascii characters (contributed by L. Thery). +- New library FSets+FMaps of finite sets and maps. +- New library QArith on rational numbers. +- Small extension of Zmin.V, new Zmax.v, new Zminmax.v. +- Reworking and extension of the files on classical logic and + description principles (possible incompatibilities) +- Few other improvements in ZArith potentially exceptionally breaking the + compatibility (useless hypothesys of Zgt_square_simpl and + Zlt_square_simpl removed; fixed names mentioning letter O instead of + digit 0; weaken premises in Z_lt_induction). +- Restructuration of Eqdep_dec.v and Eqdep.v: more lemmas in Type. +- Znumtheory now contains a gcd function that can compute within Coq. +- More lemmas stated on Type in Wf.v, removal of redundant Acc_iter and + Acc_iter2. +- Change of the internal names of lemmas in OmegaLemmas. +- Acc in Wf.v and clos_refl_trans in Relation_Operators.v now rely on + the allowance for recursively non uniform parameters (possible + source of incompatibilities: explicit pattern-matching on these + types may require to remove the occurrence associated to their + recursively non uniform parameter). +- Coq.List.In_dec has been set transparent (this may exceptionally break + proof scripts, set it locally opaque for compatibility). +- More on permutations of lists in List.v and Permutation.v. +- List.v has been much expanded. +- New file SetoidList.v now contains results about lists seen with + respect to a setoid equality. +- Library NArith has been expanded, mostly with results coming from + Intmap (for instance a bitwise xor), plus also a bridge between N and + Bitvector. +- Intmap has been reorganized. In particular its address type "addr" is + now N. User contributions known to use Intmap have been adapted + accordingly. If you're using this library please contact us. + A wrapper FMapIntMap now presents Intmap as a particular implementation + of FMaps. New developments are strongly encouraged to use either this + wrapper or any other implementations of FMap instead of using directly + this obsolete Intmap. + +Tools + +- New semantics for coqtop options ("-batch" expects option "-top dir" + for loading vernac file that contains definitions). +- Tool coq_makefile now removes custom targets that are file names in + "make clean" +- New environment variable COQREMOTEBROWSER to set the command invoked + to start the remote browser both in Coq and coqide. Standard syntax: + "%s" is the placeholder for the URL. + +Details of changes in 8.1gamma +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Syntax + +- changed parsing precedence of let/in and fun constructions of Ltac: + let x := t in e1; e2 is now parsed as let x := t in (e1;e2). + +Language and commands + +- Added sort-polymorphism for definitions in Type (but finally abandonned). +- Support for implicit arguments in the types of parameters in + (co-)fixpoints and (co-)inductive declarations. +- Improved type inference: use as much of possible general information. + before applying irreversible unification heuristics (allow e.g. to + infer the predicate in "(exist _ 0 (refl_equal 0) : {n:nat | n=0 })"). +- Support for Miller-Pfenning's patterns unification in type synthesis + (e.g. can infer P such that P x y = phi(x,y)). +- Support for "where" clause in cofixpoint definitions. +- New option "Set Printing Universes" for making Type levels explicit. + +Tactics + +- Improved implementation of the ring and field tactics. For compatibility + reasons, the previous tactics are renamed as legacy ring and legacy field, + but should be considered as deprecated. +- New declarative mathematical proof language. +- Support for argument lists of arbitrary length in Tactic Notation. +- ``rewrite ... in H`` now fails if ``H`` is used either in an hypothesis + or in the goal. +- The semantics of ``rewrite ... in *`` has been slightly modified (see doc). +- Support for ``as`` clause in tactic injection. +- New forward-reasoning tactic "apply in". +- Ltac fresh operator now builds names from a concatenation of its arguments. +- New ltac tactic "remember" to abstract over a subterm and keep an equality +- Support for Miller-Pfenning's patterns unification in apply/rewrite/... + (may lead to few incompatibilities - generally now useless tactic calls). + +Bug fixes + +- Fix for notations involving basic "match" expressions. +- Numerous other bugs solved (a few fixes may lead to incompatibilities). + +Details of changes in 8.1 +~~~~~~~~~~~~~~~~~~~~~~~~~ + +Bug fixes + +- Many bugs have been fixed (cf coq-bugs web page) + +Tactics + +- New tactics ring, ring_simplify and new tactic field now able to manage + power to a positive integer constant. Tactic ring on Z and R, and + field on R manage power (may lead to incompatibilities with V8.1gamma). +- Tactic field_simplify now applicable in hypotheses. +- New field_simplify_eq for simplifying field equations into ring equations. +- Tactics ring, ring_simplify, field, field_simplify and field_simplify_eq + all able to apply user-given equations to rewrite monoms on the fly + (see documentation). + +Libraries + +- New file ConstructiveEpsilon.v defining an epsilon operator and + proving the axiom of choice constructively for a countable domain + and a decidable predicate. + +Version 8.0 +----------- + +Summary of changes +~~~~~~~~~~~~~~~~~~ + +Coq version 8 is a major revision of the |Coq| proof assistant. First, the +underlying logic is slightly different. The so-called *impredicativity* +of the sort Set has been dropped. The main reason is that it is +inconsistent with the principle of description which is quite a useful +principle for formalizing mathematics within classical logic. Moreover, +even in an constructive setting, the impredicativity of Set does not add +so much in practice and is even subject of criticism from a large part +of the intuitionistic mathematician community. Nevertheless, the +impredicativity of Set remains optional for users interested in +investigating mathematical developments which rely on it. + +Secondly, the concrete syntax of terms has been completely revised. The +main motivations were + +- a more uniform, purified style: all constructions are now lowercase, + with a functional programming perfume (e.g. abstraction is now + written fun), and more directly accessible to the novice (e.g. + dependent product is now written forall and allows omission of + types). Also, parentheses are no longer mandatory for function + application. + +- extensibility: some standard notations (e.g. “<” and “>”) were + incompatible with the previous syntax. Now all standard arithmetic + notations (=, +, \*, /, <, <=, ... and more) are directly part of the + syntax. + +Together with the revision of the concrete syntax, a new mechanism of +*interpretation scopes* permits to reuse the same symbols (typically +, +-, \*, /, <, <=) in various mathematical theories without any +ambiguities for |Coq|, leading to a largely improved readability of |Coq| +scripts. New commands to easily add new symbols are also provided. + +Coming with the new syntax of terms, a slight reform of the tactic +language and of the language of commands has been carried out. The +purpose here is a better uniformity making the tactics and commands +easier to use and to remember. + +Thirdly, a restructuring and uniformization of the standard library of +Coq has been performed. There is now just one Leibniz equality usable +for all the different kinds of |Coq| objects. Also, the set of real +numbers now lies at the same level as the sets of natural and integer +numbers. Finally, the names of the standard properties of numbers now +follow a standard pattern and the symbolic notations for the standard +definitions as well. + +The fourth point is the release of |CoqIDE|, a new graphical gtk2-based +interface fully integrated with |Coq|. Close in style to the Proof General +Emacs interface, it is faster and its integration with |Coq| makes +interactive developments more friendly. All mathematical Unicode symbols +are usable within |CoqIDE|. + +Finally, the module system of |Coq| completes the picture of |Coq| version +8.0. Though released with an experimental status in the previous version +7.4, it should be considered as a salient feature of the new version. + +Besides, |Coq| comes with its load of novelties and improvements: new or +improved tactics (including a new tactic for solving first-order +statements), new management commands, extended libraries. + +Bruno Barras and Hugo Herbelin have been the main contributors of the +reflection and the implementation of the new syntax. The smart automatic +translator from old to new syntax released with |Coq| is also their work +with contributions by Olivier Desmettre. + +Hugo Herbelin is the main designer and implementer of the notion of +interpretation scopes and of the commands for easily adding new +notations. + +Hugo Herbelin is the main implementer of the restructured standard library. + +Pierre Corbineau is the main designer and implementer of the new tactic +for solving first-order statements in presence of inductive types. He is +also the maintainer of the non-domain specific automation tactics. + +Benjamin Monate is the developer of the |CoqIDE| graphical interface with +contributions by Jean-Christophe Filliâtre, Pierre Letouzey, Claude +Marché and Bruno Barras. + +Claude Marché coordinated the edition of the Reference Manual for |Coq| +V8.0. + +Pierre Letouzey and Jacek Chrząszcz respectively maintained the +extraction tool and module system of |Coq|. + +Jean-Christophe Filliâtre, Pierre Letouzey, Hugo Herbelin and other +contributors from Sophia-Antipolis and Nijmegen participated in +extending the library. + +Julien Narboux built a NSIS-based automatic |Coq| installation tool for +the Windows platform. + +Hugo Herbelin and Christine Paulin coordinated the development which was +under the responsibility of Christine Paulin. + +| Palaiseau & Orsay, Apr. 2004 +| Hugo Herbelin & Christine Paulin +| (updated Apr. 2006) +| + +Details of changes in 8.0beta old syntax +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Logic + +- Set now predicative by default +- New option -impredicative-set to set Set impredicative +- The standard library doesn't need impredicativity of Set and is + compatible with the classical axioms which contradict Set impredicativity + +Syntax for arithmetic + +- Notation "=" and "<>" in Z and R are no longer implicitly in Z or R + (with possible introduction of a coercion), use <Z>...=... or + <Z>...<>... instead +- Locate applied to a simple string (e.g. "+") searches for all + notations containing this string + +Vernacular commands + +- "Declare ML Module" now allows to import .cma files. This avoids to use a + bunch of "Declare ML Module" statements when using several ML files. +- "Set Printing Width n" added, allows to change the size of width printing. +- "Implicit Variables Type x,y:t" (new syntax: "Implicit Types x y:t") + assigns default types for binding variables. +- Declarations of Hints and Notation now accept a "Local" flag not to + be exported outside the current file even if not in section +- "Print Scopes" prints all notations +- New command "About name" for light printing of type, implicit arguments, etc. +- New command "Admitted" to declare incompletely proven statement as axioms +- New keyword "Conjecture" to declare an axiom intended to be provable +- SearchAbout can now search for lemmas referring to more than one constant + and on substrings of the name of the lemma +- "Print Implicit" displays the implicit arguments of a constant +- Locate now searches for all names having a given suffix +- New command "Functional Scheme" for building an induction principle + from a function defined by case analysis and fix. + +Commands + +- new coqtop/coqc option -dont-load-proofs not to load opaque proofs in memory + +Implicit arguments + +- Inductive in sections declared with implicits now "discharged" with + implicits (like constants and variables) +- Implicit Arguments flags are now synchronous with reset +- New switch "Unset/Set Printing Implicits" (new syntax: "Unset/Set Printing + Implicit") to globally control printing of implicits + +Grammar extensions + +- Many newly supported UTF-8 encoded unicode blocks + - Greek letters (0380-03FF), Hebrew letters (U05D0-05EF), letter-like + symbols (2100-214F, that includes double N,Z,Q,R), prime + signs (from 2080-2089) and characters from many written languages + are valid in identifiers + - mathematical operators (2200-22FF), supplemental mathematical + operators (2A00-2AFF), miscellaneous technical (2300-23FF that + includes sqrt symbol), miscellaneous symbols (2600-26FF), arrows + (2190-21FF and 2900-297F), invisible mathematical operators (from + 2080-2089), ... are valid symbols + +Library + +- New file about the factorial function in Arith + +- An additional elimination Acc_iter for Acc, simplier than Acc_rect. + This new elimination principle is used for definition well_founded_induction. + +- New library NArith on binary natural numbers + +- R is now of type Set + +- Restructuration in ZArith library + + + "true_sub" used in Zplus now a definition, not a local one (source + of incompatibilities in proof referring to true_sub, may need extra Unfold) + + Some lemmas about minus moved from fast_integer to Arith/Minus.v + (le_minus, lt_mult_left) (theoretical source of incompatibilities) + + Several lemmas moved from auxiliary.v and zarith_aux.v to + fast_integer.v (theoretical source of incompatibilities) + + Variables names of iff_trans changed (source of incompatibilities) + + ZArith lemmas named ``OMEGA`` something or ``fast_`` something, and lemma ``new_var`` + are now out of ZArith (except ``OMEGA2``) + + Redundant ZArith lemmas have been renamed: for the following pairs, + use the second name (Zle_Zmult_right2, Zle_mult_simpl), (OMEGA2, + Zle_0_plus), (Zplus_assoc_l, Zplus_assoc), (Zmult_one, Zmult_1_n), + (Zmult_assoc_l, Zmult_assoc), (Zmult_minus_distr, Zmult_Zminus_distr_l) + (add_un_double_moins_un_xO, is_double_moins_un), + (Rlt_monotony_rev,Rlt_monotony_contra) (source of incompatibilities) + +- Few minor changes (no more implicit arguments in + Zmult_Zminus_distr_l and Zmult_Zminus_distr_r, lemmas moved from + Zcomplements to other files) (rare source of incompatibilities) + +- New lemmas provided by users added + +Tactic language + +- Fail tactic now accepts a failure message +- Idtac tactic now accepts a message +- New primitive tactic "FreshId" (new syntax: "fresh") to generate new names +- Debugger prints levels of calls + +Tactics + +- Replace can now replace proofs also +- Fail levels are now decremented at "Match Context" blocks only and + if the right-hand-side of "Match term With" are tactics, these + tactics are never evaluated immediately and do not induce + backtracking (in contrast with "Match Context") +- Quantified names now avoid global names of the current module (like + Intro names did) [source of rare incompatibilities: 2 changes in the set of + user contribs] +- NewDestruct/NewInduction accepts intro patterns as introduction names +- NewDestruct/NewInduction now work for non-inductive type using option "using" +- A NewInduction naming bug for inductive types with functional + arguments (e.g. the accessibility predicate) has been fixed (source + of incompatibilities) +- Symmetry now applies to hypotheses too +- Inversion now accept option "as [ ... ]" to name the hypotheses +- Contradiction now looks also for contradictory hypotheses stating ~A and A + (source of incompatibility) +- "Contradiction c" try to find an hypothesis in context which + contradicts the type of c +- Ring applies to new library NArith (require file NArithRing) +- Field now works on types in Set +- Auto with reals now try to replace le by ge (Rge_le is no longer an + immediate hint), resulting in shorter proofs +- Instantiate now works in hyps (syntax : Instantiate in ...) +- Some new tactics : EConstructor, ELeft, Eright, ESplit, EExists +- New tactic "functional induction" to perform case analysis and + induction following the definition of a function. +- Clear now fails when trying to remove a local definition used by + a constant appearing in the current goal + +Extraction (See details in plugins/extraction/CHANGES) + +- The old commands: (Recursive) Extraction Module M. + are now: (Recursive) Extraction Library M. + To use these commands, M should come from a library M.v +- The other syntax Extraction & Recursive Extraction now accept + module names as arguments. + +Bugs + +- see coq-bugs server for the complete list of fixed bugs + +Miscellaneous + +- Implicit parameters of inductive types definition now taken into + account for infering other implicit arguments + +Incompatibilities + +- Persistence of true_sub (4 incompatibilities in Coq user contributions) +- Variable names of some constants changed for a better uniformity (2 changes + in Coq user contributions) +- Naming of quantified names in goal now avoid global names (2 occurrences) +- NewInduction naming for inductive types with functional arguments + (no incompatibility in Coq user contributions) +- Contradiction now solve more goals (source of 2 incompatibilities) +- Merge of eq and eqT may exceptionally result in subgoals now + solved automatically +- Redundant pairs of ZArith lemmas may have different names: it may + cause "Apply/Rewrite with" to fail if using the first name of a pair + of redundant lemmas (this is solved by renaming the variables bound by + "with"; 3 incompatibilities in Coq user contribs) +- ML programs referring to constants from fast_integer.v must use + "Coqlib.gen_constant_modules Coqlib.zarith_base_modules" instead + +Details of changes in 8.0beta new syntax +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +New concrete syntax + +- A completely new syntax for terms +- A more uniform syntax for tactics and the tactic language +- A few syntactic changes for vernacular commands +- A smart automatic translator translating V8.0 files in old syntax to + files valid for V8.0 + +Syntax extensions + +- "Grammar" for terms disappears +- "Grammar" for tactics becomes "Tactic Notation" +- "Syntax" disappears +- Introduction of a notion of interpretation scope allowing to use the + same notations in various contexts without using specific delimiters + (e.g the same expression "4<=3+x" is interpreted either in "nat", + "positive", "N" (previously "entier"), "Z", "R", depending on which + interpretation scope is currently open) [see documentation for details] +- Notation now mandatorily requires a precedence and associativity + (default was to set precedence to 1 and associativity to none) + +Revision of the standard library + +- Many lemmas and definitions names have been made more uniform mostly + in Arith, NArith, ZArith and Reals (e.g : "times" -> "Pmult", + "times_sym" -> "Pmult_comm", "Zle_Zmult_pos_right" -> + "Zmult_le_compat_r", "SUPERIEUR" -> "Gt", "ZERO" -> "Z0") +- Order and names of arguments of basic lemmas on nat, Z, positive and R + have been made uniform. +- Notions of Coq initial state are declared with (strict) implicit arguments +- eq merged with eqT: old eq disappear, new eq (written =) is old eqT + and new eqT is syntactic sugar for new eq (notation == is an alias + for = and is written as it, exceptional source of incompatibilities) +- Similarly, ex, ex2, all, identity are merged with exT, exT2, allT, identityT +- Arithmetical notations for nat, positive, N, Z, R, without needing + any backquote or double-backquotes delimiters. +- In Lists: new concrete notations; argument of nil is now implicit +- All changes in the library are taken in charge by the translator + +Semantical changes during translation + +- Recursive keyword set by default (and no longer needed) in Tactic Definition +- Set Implicit Arguments is strict by default in new syntax +- reductions in hypotheses of the form "... in H" now apply to the type + also if H is a local definition +- etc + +Gallina + +- New syntax of the form "Inductive bool : Set := true, false : bool." for + enumerated types +- Experimental syntax of the form p.(fst) for record projections + (activable with option "Set Printing Projections" which is + recognized by the translator) + +Known problems of the automatic translation + +- iso-latin-1 characters are no longer supported: move your files to + 7-bits ASCII or unicode before translation (swith to unicode is + automatically done if a file is loaded and saved again by coqide) +- Renaming in ZArith: incompatibilities in Coq user contribs due to + merging names INZ, from Reals, and inject_nat. +- Renaming and new lemmas in ZArith: may clash with names used by users +- Restructuration of ZArith: replace requirement of specific modules + in ZArith by "Require Import ZArith_base" or "Require Import ZArith" +- Some implicit arguments must be made explicit before translation: typically + for "length nil", the implicit argument of length must be made explicit +- Grammar rules, Infix notations and V7.4 Notations must be updated wrt the + new scheme for syntactic extensions (see translator documentation) +- Unsafe for annotation Cases when constructors coercions are used or when + annotations are eta-reduced predicates + +Details of changes in 8.0 +~~~~~~~~~~~~~~~~~~~~~~~~~ + +Vernacular commands + +- New option "Set Printing All" to deactivate all high-level forms of + printing (implicit arguments, coercions, destructing let, + if-then-else, notations, projections) +- "Functional Scheme" and "Functional Induction" extended to polymorphic + types and dependent types +- Notation now allows recursive patterns, hence recovering parts of the + fonctionalities of pre-V8 Grammar/Syntax commands +- Command "Print." discontinued. +- Redundant syntax "Implicit Arguments On/Off" discontinued + +New syntax + +- Semantics change of the if-then-else construction in new syntax: + "if c then t1 else t2" now stands for + "match c with c1 _ ... _ => t1 | c2 _ ... _ => t2 end" + with no dependency of t1 and t2 in the arguments of the constructors; + this may cause incompatibilities for files translated using coq 8.0beta + +Interpretation scopes + +- Delimiting key %bool for bool_scope added +- Import no more needed to activate argument scopes from a module + +Tactics and the tactic Language + +- Semantics of "assert" is now consistent with the reference manual +- New tactics stepl and stepr for chaining transitivity steps +- Tactic "replace ... with ... in" added +- Intro patterns now supported in Ltac (parsed with prefix "ipattern:") + +Executables and tools + +- Added option -top to change the name of the toplevel module "Top" +- Coqdoc updated to new syntax and now part of Coq sources +- XML exportation tool now exports the structure of vernacular files + (cf chapter 13 in the reference manual) + +User contributions + +- User contributions have been updated to the new syntax + +Bug fixes + +- Many bugs have been fixed (cf coq-bugs web page) diff --git a/doc/sphinx/credits.rst b/doc/sphinx/credits.rst deleted file mode 100644 index 5873096523..0000000000 --- a/doc/sphinx/credits.rst +++ /dev/null @@ -1,1884 +0,0 @@ -------- -Credits -------- - -Historical roots ----------------- - -Coq is a proof assistant for higher-order logic, allowing the -development of computer programs consistent with their formal -specification. It is the result of about ten years [#years]_ of research -of the Coq project. We shall briefly survey here three main aspects: the -*logical language* in which we write our axiomatizations and -specifications, the *proof assistant* which allows the development of -verified mathematical proofs, and the *program extractor* which -synthesizes computer programs obeying their formal specifications, -written as logical assertions in the language. - -The logical language used by |Coq| is a variety of type theory, called the -*Calculus of Inductive Constructions*. Without going back to Leibniz and -Boole, we can date the creation of what is now called mathematical logic -to the work of Frege and Peano at the turn of the century. The discovery -of antinomies in the free use of predicates or comprehension principles -prompted Russell to restrict predicate calculus with a stratification of -*types*. This effort culminated with *Principia Mathematica*, the first -systematic attempt at a formal foundation of mathematics. A -simplification of this system along the lines of simply typed -λ-calculus occurred with Church’s *Simple Theory of -Types*. The λ-calculus notation, originally used for -expressing functionality, could also be used as an encoding of natural -deduction proofs. This Curry-Howard isomorphism was used by N. de Bruijn -in the *Automath* project, the first full-scale attempt to develop and -mechanically verify mathematical proofs. This effort culminated with -Jutting’s verification of Landau’s *Grundlagen* in the 1970’s. -Exploiting this Curry-Howard isomorphism, notable achievements in proof -theory saw the emergence of two type-theoretic frameworks; the first -one, Martin-Löf’s *Intuitionistic Theory of Types*, attempts a new -foundation of mathematics on constructive principles. The second one, -Girard’s polymorphic λ-calculus :math:`F_\omega`, is a -very strong functional system in which we may represent higher-order -logic proof structures. Combining both systems in a higher-order -extension of the Automath language, T. Coquand presented in 1985 the -first version of the *Calculus of Constructions*, CoC. This strong -logical system allowed powerful axiomatizations, but direct inductive -definitions were not possible, and inductive notions had to be defined -indirectly through functional encodings, which introduced inefficiencies -and awkwardness. The formalism was extended in 1989 by T. Coquand and C. -Paulin with primitive inductive definitions, leading to the current -*Calculus of Inductive Constructions*. This extended formalism is not -rigorously defined here. Rather, numerous concrete examples are -discussed. We refer the interested reader to relevant research papers -for more information about the formalism, its meta-theoretic properties, -and semantics. However, it should not be necessary to understand this -theoretical material in order to write specifications. It is possible to -understand the Calculus of Inductive Constructions at a higher level, as -a mixture of predicate calculus, inductive predicate definitions -presented as typed PROLOG, and recursive function definitions close to -the language ML. - -Automated theorem-proving was pioneered in the 1960’s by Davis and -Putnam in propositional calculus. A complete mechanization (in the sense -of a semidecision procedure) of classical first-order logic was -proposed in 1965 by J.A. Robinson, with a single uniform inference rule -called *resolution*. Resolution relies on solving equations in free -algebras (i.e. term structures), using the *unification algorithm*. Many -refinements of resolution were studied in the 1970’s, but few convincing -implementations were realized, except of course that PROLOG is in some -sense issued from this effort. A less ambitious approach to proof -development is computer-aided proof-checking. The most notable -proof-checkers developed in the 1970’s were LCF, designed by R. Milner -and his colleagues at U. Edinburgh, specialized in proving properties -about denotational semantics recursion equations, and the Boyer and -Moore theorem-prover, an automation of primitive recursion over -inductive data types. While the Boyer-Moore theorem-prover attempted to -synthesize proofs by a combination of automated methods, LCF constructed -its proofs through the programming of *tactics*, written in a high-level -functional meta-language, ML. - -The salient feature which clearly distinguishes our proof assistant from -say LCF or Boyer and Moore’s, is its possibility to extract programs -from the constructive contents of proofs. This computational -interpretation of proof objects, in the tradition of Bishop’s -constructive mathematics, is based on a realizability interpretation, in -the sense of Kleene, due to C. Paulin. The user must just mark his -intention by separating in the logical statements the assertions stating -the existence of a computational object from the logical assertions -which specify its properties, but which may be considered as just -comments in the corresponding program. Given this information, the -system automatically extracts a functional term from a consistency proof -of its specifications. This functional term may be in turn compiled into -an actual computer program. This methodology of extracting programs from -proofs is a revolutionary paradigm for software engineering. Program -synthesis has long been a theme of research in artificial intelligence, -pioneered by R. Waldinger. The Tablog system of Z. Manna and R. -Waldinger allows the deductive synthesis of functional programs from -proofs in tableau form of their specifications, written in a variety of -first-order logic. Development of a systematic *programming logic*, -based on extensions of Martin-Löf’s type theory, was undertaken at -Cornell U. by the Nuprl team, headed by R. Constable. The first actual -program extractor, PX, was designed and implemented around 1985 by S. -Hayashi from Kyoto University. It allows the extraction of a LISP -program from a proof in a logical system inspired by the logical -formalisms of S. Feferman. Interest in this methodology is growing in -the theoretical computer science community. We can foresee the day when -actual computer systems used in applications will contain certified -modules, automatically generated from a consistency proof of their -formal specifications. We are however still far from being able to use -this methodology in a smooth interaction with the standard tools from -software engineering, i.e. compilers, linkers, run-time systems taking -advantage of special hardware, debuggers, and the like. We hope that |Coq| -can be of use to researchers interested in experimenting with this new -methodology. - -.. [#years] At the time of writting, i.e. 1995. - -Brief summary of the versions up to 5.10 ----------------------------------------- - -.. note:: - This summary was written in 1995 together with the previous - section and formed the initial version of the Credits chapter - (that has since then been appended to, at each new release). - A more comprehensive description of these early versions is - available in the next few sections, which were written in 2015. - -A first implementation of CoC was started in 1984 by G. Huet and T. -Coquand. Its implementation language was CAML, a functional programming -language from the ML family designed at INRIA in Rocquencourt. The core -of this system was a proof-checker for CoC seen as a typed -λ-calculus, called the *Constructive Engine*. This engine -was operated through a high-level notation permitting the declaration of -axioms and parameters, the definition of mathematical types and objects, -and the explicit construction of proof objects encoded as -λ-terms. A section mechanism, designed and implemented by -G. Dowek, allowed hierarchical developments of mathematical theories. -This high-level language was called the *Mathematical Vernacular*. -Furthermore, an interactive *Theorem Prover* permitted the incremental -construction of proof trees in a top-down manner, subgoaling recursively -and backtracking from dead-ends. The theorem prover executed tactics -written in CAML, in the LCF fashion. A basic set of tactics was -predefined, which the user could extend by his own specific tactics. -This system (Version 4.10) was released in 1989. Then, the system was -extended to deal with the new calculus with inductive types by C. -Paulin, with corresponding new tactics for proofs by induction. A new -standard set of tactics was streamlined, and the vernacular extended for -tactics execution. A package to compile programs extracted from proofs -to actual computer programs in CAML or some other functional language -was designed and implemented by B. Werner. A new user-interface, relying -on a CAML-X interface by D. de Rauglaudre, was designed and implemented -by A. Felty. It allowed operation of the theorem-prover through the -manipulation of windows, menus, mouse-sensitive buttons, and other -widgets. This system (Version 5.6) was released in 1991. - -Coq was ported to the new implementation Caml-light of X. Leroy and D. -Doligez by D. de Rauglaudre (Version 5.7) in 1992. A new version of |Coq| -was then coordinated by C. Murthy, with new tools designed by C. Parent -to prove properties of ML programs (this methodology is dual to program -extraction) and a new user-interaction loop. This system (Version 5.8) -was released in May 1993. A Centaur interface CTCoq was then developed -by Y. Bertot from the Croap project from INRIA-Sophia-Antipolis. - -In parallel, G. Dowek and H. Herbelin developed a new proof engine, -allowing the general manipulation of existential variables consistently -with dependent types in an experimental version of |Coq| (V5.9). - -The version V5.10 of |Coq| is based on a generic system for manipulating -terms with binding operators due to Chet Murthy. A new proof engine -allows the parallel development of partial proofs for independent -subgoals. The structure of these proof trees is a mixed representation -of derivation trees for the Calculus of Inductive Constructions with -abstract syntax trees for the tactics scripts, allowing the navigation -in a proof at various levels of details. The proof engine allows generic -environment items managed in an object-oriented way. This new -architecture, due to C. Murthy, supports several new facilities which -make the system easier to extend and to scale up: - -- User-programmable tactics are allowed - -- It is possible to separately verify development modules, and to load - their compiled images without verifying them again - a quick - relocation process allows their fast loading - -- A generic parsing scheme allows user-definable notations, with a - symmetric table-driven pretty-printer - -- Syntactic definitions allow convenient abbreviations - -- A limited facility of meta-variables allows the automatic synthesis - of certain type expressions, allowing generic notations for e.g. - equality, pairing, and existential quantification. - -In the Fall of 1994, C. Paulin-Mohring replaced the structure of -inductively defined types and families by a new structure, allowing the -mutually recursive definitions. P. Manoury implemented a translation of -recursive definitions into the primitive recursive style imposed by the -internal recursion operators, in the style of the ProPre system. C. -Muñoz implemented a decision procedure for intuitionistic propositional -logic, based on results of R. Dyckhoff. J.C. Filliâtre implemented a -decision procedure for first-order logic without contraction, based on -results of J. Ketonen and R. Weyhrauch. Finally C. Murthy implemented a -library of inversion tactics, relieving the user from tedious -definitions of “inversion predicates”. - -| Rocquencourt, Feb. 1st 1995 -| Gérard Huet -| - -Version 1 ---------- - -.. note:: - - These additional notes come from a document written - in September 2015 by Gérard Huet, Thierry Coquand and Christine Paulin - to accompany their public release of the archive of versions 1.10 to 6.2 - of Coq and of its CONSTR ancestor. CONSTR, then Coq, was designed and - implemented in the Formel team, joint between the INRIA Rocquencourt - laboratory and the Ecole Normale Supérieure of Paris, from 1984 - onwards. - -This software is a prototype type-checker for a higher-order logical -formalism known as the Theory of Constructions, presented in his PhD -thesis by Thierry Coquand, with influences from Girard's system F and -de Bruijn's Automath. The metamathematical analysis of the system is -the PhD work of Thierry Coquand. The software is mostly the work of -Gérard Huet. Most of the mathematical examples verified with the -software are due to Thierry Coquand. - -The programming language of the CONSTR software (as it was called at -the time) was a version of ML adapted from the Edinburgh LCF system -and running on a LISP backend. The main improvements from the original -LCF ML were that ML was compiled rather than interpreted (Gérard Huet -building on the original translator by Lockwood Morris), and that it -was enriched by recursively defined types (work of Guy -Cousineau). This ancestor of CAML was used and improved by Larry -Paulson for his implementation of Cambridge LCF. - -Software developments of this prototype occurred from late 1983 to -early 1985. - -Version 1.10 was frozen on December 22nd 1984. It is the version used -for the examples in Thierry Coquand's thesis, defended on January 31st -1985. There was a unique binding operator, used both for universal -quantification (dependent product) at the level of types and -functional abstraction (λ) at the level of terms/proofs, in the manner -of Automath. Substitution (λ-reduction) was implemented using de -Bruijn's indexes. - -Version 1.11 was frozen on February 19th, 1985. It is the version used -for the examples in the paper: T. Coquand, G. Huet. *Constructions: A -Higher Order Proof System for Mechanizing Mathematics* :cite:`CH85`. - -Christine Paulin joined the team at this point, for her DEA research -internship. In her DEA memoir (August 1985) she presents developments -for the *lambo* function – :math:`\text{lambo}(f)(n)` computes the minimal -:math:`m` such that :math:`f(m)` is greater than :math:`n`, for :math:`f` -an increasing integer function, a challenge for constructive mathematics. -She also encoded the majority voting algorithm of Boyer and Moore. - -Version 2 ---------- - -The formal system, now renamed as the *Calculus of Constructions*, was -presented with a proof of consistency and comparisons with proof -systems of Per Martin Löf, Girard, and the Automath family of N. de -Bruijn, in the paper: T. Coquand and G. Huet. *The Calculus of -Constructions* :cite:`CH88`. - -An abstraction of the software design, in the form of an abstract -machine for proof checking, and a fuller sequence of mathematical -developments was presented in: T. Coquand, G. Huet. *Concepts -Mathématiques et Informatiques Formalisés dans le Calcul des -Constructions* :cite:`CH87`. - -Version 2.8 was frozen on December 16th, 1985, and served for -developing the examples in the above papers. - -This calculus was then enriched in version 2.9 with a cumulative -hierarchy of universes. Universe levels were initially explicit -natural numbers. Another improvement was the possibility of automatic -synthesis of implicit type arguments, relieving the user of tedious -redundant declarations. - -Christine Paulin wrote an article *Algorithm development in the -Calculus of Constructions* :cite:`P86`. Besides *lambo* and *majority*, -she presents *quicksort* and a text formatting algorithm. - -Version 2.13 of the Calculus of Constructions with universes was -frozen on June 25th, 1986. - -A synthetic presentation of type theory along constructive lines with -ML algorithms was given by Gérard Huet in his May 1986 CMU course -notes *Formal Structures for Computation and Deduction*. Its chapter -*Induction and Recursion in the Theory of Constructions* was presented -as an invited paper at the Joint Conference on Theory and Practice of -Software Development TAPSOFT’87 at Pise in March 1987, and published -as *Induction Principles Formalized in the Calculus of -Constructions* :cite:`H88`. - -Version 3 ---------- - -This version saw the beginning of proof automation, with a search -algorithm inspired from PROLOG and the applicative logic programming -programs of the course notes *Formal structures for computation and -deduction*. The search algorithm was implemented in ML by Thierry -Coquand. The proof system could thus be used in two modes: proof -verification and proof synthesis, with tactics such as ``AUTO``. - -The implementation language was now called CAML, for Categorical -Abstract Machine Language. It used as backend the LLM3 virtual machine -of Le Lisp by Jérôme Chailloux. The main developers of CAML were -Michel Mauny, Ascander Suarez and Pierre Weis. - -V3.1 was started in the summer of 1986, V3.2 was frozen at the end of -November 1986. V3.4 was developed in the first half of 1987. - -Thierry Coquand held a post-doctoral position in Cambrige University -in 1986-87, where he developed a variant implementation in SML, with -which he wrote some developments on fixpoints in Scott's domains. - -Version 4 ---------- - -This version saw the beginning of program extraction from proofs, with -two varieties of the type ``Prop`` of propositions, indicating -constructive intent. The proof extraction algorithms were implemented -by Christine Paulin-Mohring. - -V4.1 was frozen on July 24th, 1987. It had a first identified library -of mathematical developments (directory ``exemples``), with libraries -``Logic`` (containing impredicative encodings of intuitionistic logic and -algebraic primitives for booleans, natural numbers and list), ``Peano`` -developing second-order Peano arithmetic, ``Arith`` defining addition, -multiplication, euclidean division and factorial. Typical developments -were the Knaster-Tarski theorem and Newman's lemma from rewriting -theory. - -V4.2 was a joint development of a team consisting of Thierry Coquand, -Gérard Huet and Christine Paulin-Mohring. A file V4.2.log records the -log of changes. It was frozen on September 1987 as the last version -implemented in CAML 2.3, and V4.3 followed on CAML 2.5, a more stable -development system. - -V4.3 saw the first top-level of the system. Instead of evaluating -explicit quotations, the user could develop his mathematics in a -high-level language called the mathematical vernacular (following -Automath terminology). The user could develop files in the vernacular -notation (with ``.v`` extension) which were now separate from the ``ml`` -sources of the implementation. Gilles Dowek joined the team to -develop the vernacular language as his DEA internship research. - -A notion of sticky constant was introduced, in order to keep names of -lemmas when local hypotheses of proofs were discharged. This gave a -notion of global mathematical environment with local sections. - -Another significant practical change was that the system, originally -developped on the VAX central computer of our lab, was transferred on -SUN personal workstations, allowing a level of distributed -development. The extraction algorithm was modified, with three -annotations ``Pos``, ``Null`` and ``Typ`` decorating the sorts ``Prop`` -and ``Type``. - -Version 4.3 was frozen at the end of November 1987, and was -distributed to an early community of users (among those were Hugo -Herbelin and Loic Colson). - -V4.4 saw the first version of (encoded) inductive types. Now natural -numbers could be defined as:: - - [source, coq] - Inductive NAT : Prop = O : NAT | Succ : NAT->NAT. - -These inductive types were encoded impredicatively in the calculus, -using a subsystem *rec* due to Christine Paulin. V4.4 was frozen on -March 6th 1988. - -Version 4.5 was the first one to support inductive types and program -extraction. Its banner was *Calcul des Constructions avec -Réalisations et Synthèse*. The vernacular language was enriched to -accommodate extraction commands. - -The verification engine design was presented as: G. Huet. *The -Constructive Engine*. Version 4.5. Invited Conference, 2nd European -Symposium on Programming, Nancy, March 88. The final paper, -describing the V4.9 implementation, appeared in: A perspective in -Theoretical Computer Science, Commemorative Volume in memory of Gift -Siromoney, Ed. R. Narasimhan, World Scientific Publishing, 1989. - -Version 4.5 was demonstrated in June 1988 at the YoP Institute on -Logical Foundations of Functional Programming organized by Gérard Huet -at Austin, Texas. - -Version 4.6 was started during the summer of 1988. Its main -improvement was the complete rehaul of the proof synthesis engine by -Thierry Coquand, with a tree structure of goals. - -Its source code was communicated to Randy Pollack on September 2nd -1988. It evolved progressively into LEGO, proof system for Luo's -formalism of Extended Calculus of Constructions. - -The discharge tactic was modified by Gérard Huet to allow for -inter-dependencies in discharged lemmas. Christine Paulin improved the -inductive definition scheme in order to accommodate predicates of any -arity. - -Version 4.7 was started on September 6th, 1988. - -This version starts exploiting the CAML notion of module in order to -improve the modularity of the implementation. Now the term verifier is -identified as a proper module Machine, which the structure of its -internal data structures being hidden and thus accessible only through -the legitimate operations. This machine (the constructive engine) was -the trusted core of the implementation. The proof synthesis mechanism -was a separate proof term generator. Once a complete proof term was -synthesized with the help of tactics, it was entirely re-checked by -the engine. Thus there was no need to certify the tactics, and the -system took advantage of this fact by having tactics ignore the -universe levels, universe consistency check being relegated to the -final type-checking pass. This induced a certain puzzlement in early -users who saw, after a successful proof search, their ``QED`` followed -by silence, followed by a failure message due to a universe -inconsistency… - -The set of examples comprise set theory experiments by Hugo Herbelin, -and notably the Schroeder-Bernstein theorem. - -Version 4.8, started on October 8th, 1988, saw a major -re-implementation of the abstract syntax type ``constr``, separating -variables of the formalism and metavariables denoting incomplete terms -managed by the search mechanism. A notion of level (with three values -``TYPE``, ``OBJECT`` and ``PROOF``) is made explicit and a type judgement -clarifies the constructions, whose implementation is now fully -explicit. Structural equality is speeded up by using pointer equality, -yielding spectacular improvements. Thierry Coquand adapts the proof -synthesis to the new representation, and simplifies pattern matching -to first-order predicate calculus matching, with important performance -gain. - -A new representation of the universe hierarchy is then defined by -Gérard Huet. Universe levels are now implemented implicitly, through -a hidden graph of abstract levels constrained with an order relation. -Checking acyclicity of the graph insures well-foundedness of the -ordering, and thus consistency. This was documented in a memo *Adding -Type:Type to the Calculus of Constructions* which was never published. - -The development version is released as a stable 4.8 at the end of -1988. - -Version 4.9 is released on March 1st 1989, with the new "elastic" -universe hierarchy. - -The spring of 1989 saw the first attempt at documenting the system -usage, with a number of papers describing the formalism: - -- *Metamathematical Investigations of a Calculus of Constructions*, by - Thierry Coquand :cite:`C90`, - -- *Inductive definitions in the Calculus of Constructions*, by - Christine Paulin-Mohrin, - -- *Extracting Fω's programs from proofs in the Calculus of - Constructions*, by Christine Paulin-Mohring* :cite:`P89`, - -- *The Constructive Engine*, by Gérard Huet :cite:`H89`, - -as well as a number of user guides: - -- *A short user's guide for the Constructions*, Version 4.10, by Gérard Huet -- *A Vernacular Syllabus*, by Gilles Dowek. -- *The Tactics Theorem Prover, User's guide*, Version 4.10, by Thierry - Coquand. - -Stable V4.10, released on May 1st, 1989, was then a mature system, -distributed with CAML V2.6. - -In the mean time, Thierry Coquand and Christine Paulin-Mohring had -been investigating how to add native inductive types to the Calculus -of Constructions, in the manner of Per Martin-Löf's Intuitionistic -Type Theory. The impredicative encoding had already been presented in: -F. Pfenning and C. Paulin-Mohring. *Inductively defined types in the -Calculus of Constructions* :cite:`PP90`. An extension of the calculus -with primitive inductive types appeared in: T. Coquand and -C. Paulin-Mohring. *Inductively defined types* :cite:`CP90`. - -This led to the Calculus of Inductive Constructions, logical formalism -implemented in Versions 5 upward of the system, and documented in: -C. Paulin-Mohring. *Inductive Definitions in the System Coq - Rules -and Properties* :cite:`P93`. - -The last version of CONSTR is Version 4.11, which was last distributed -in the spring of 1990. It was demonstrated at the first workshop of -the European Basic Research Action Logical Frameworks In Sophia -Antipolis in May 1990. - -Version 5 ---------- - -At the end of 1989, Version 5.1 was started, and renamed as the system -Coq for the Calculus of Inductive Constructions. It was then ported to -the new stand-alone implementation of ML called Caml-light. - -In 1990 many changes occurred. Thierry Coquand left for Chalmers -University in Göteborg. Christine Paulin-Mohring took a CNRS -researcher position at the LIP laboratory of École Normale Supérieure -de Lyon. Project Formel was terminated, and gave rise to two teams: -Cristal at INRIA-Roquencourt, that continued developments in -functional programming with Caml-light then OCaml, and Coq, continuing -the type theory research, with a joint team headed by Gérard Huet at -INRIA-Rocquencourt and Christine Paulin-Mohring at the LIP laboratory -of CNRS-ENS Lyon. - -Chetan Murthy joined the team in 1991 and became the main software -architect of Version 5. He completely rehauled the implementation for -efficiency. Versions 5.6 and 5.8 were major distributed versions, -with complete documentation and a library of users' developements. The -use of the RCS revision control system, and systematic ChangeLog -files, allow a more precise tracking of the software developments. - -| September 2015 + -| Thierry Coquand, Gérard Huet and Christine Paulin-Mohring. -| - -Version 6.1 ------------ - -The present version 6.1 of |Coq| is based on the V5.10 architecture. It -was ported to the new language Objective Caml by Bruno Barras. The -underlying framework has slightly changed and allows more conversions -between sorts. - -The new version provides powerful tools for easier developments. - -Cristina Cornes designed an extension of the |Coq| syntax to allow -definition of terms using a powerful pattern matching analysis in the -style of ML programs. - -Amokrane Saïbi wrote a mechanism to simulate inheritance between types -families extending a proposal by Peter Aczel. He also developed a -mechanism to automatically compute which arguments of a constant may be -inferred by the system and consequently do not need to be explicitly -written. - -Yann Coscoy designed a command which explains a proof term using natural -language. Pierre Crégut built a new tactic which solves problems in -quantifier-free Presburger Arithmetic. Both functionalities have been -integrated to the |Coq| system by Hugo Herbelin. - -Samuel Boutin designed a tactic for simplification of commutative rings -using a canonical set of rewriting rules and equality modulo -associativity and commutativity. - -Finally the organisation of the |Coq| distribution has been supervised by -Jean-Christophe Filliâtre with the help of Judicaël Courant and Bruno -Barras. - -| Lyon, Nov. 18th 1996 -| Christine Paulin -| - -Version 6.2 ------------ - -In version 6.2 of |Coq|, the parsing is done using camlp4, a preprocessor -and pretty-printer for CAML designed by Daniel de Rauglaudre at INRIA. -Daniel de Rauglaudre made the first adaptation of |Coq| for camlp4, this -work was continued by Bruno Barras who also changed the structure of |Coq| -abstract syntax trees and the primitives to manipulate them. The result -of these changes is a faster parsing procedure with greatly improved -syntax-error messages. The user-interface to introduce grammar or -pretty-printing rules has also changed. - -Eduardo Giménez redesigned the internal tactic libraries, giving uniform -names to Caml functions corresponding to |Coq| tactic names. - -Bruno Barras wrote new, more efficient reduction functions. - -Hugo Herbelin introduced more uniform notations in the |Coq| specification -language: the definitions by fixpoints and pattern matching have a more -readable syntax. Patrick Loiseleur introduced user-friendly notations -for arithmetic expressions. - -New tactics were introduced: Eduardo Giménez improved the mechanism to -introduce macros for tactics, and designed special tactics for -(co)inductive definitions; Patrick Loiseleur designed a tactic to -simplify polynomial expressions in an arbitrary commutative ring which -generalizes the previous tactic implemented by Samuel Boutin. -Jean-Christophe Filliâtre introduced a tactic for refining a goal, using -a proof term with holes as a proof scheme. - -David Delahaye designed the tool to search an object in the library -given its type (up to isomorphism). - -Henri Laulhère produced the |Coq| distribution for the Windows -environment. - -Finally, Hugo Herbelin was the main coordinator of the |Coq| documentation -with principal contributions by Bruno Barras, David Delahaye, -Jean-Christophe Filliâtre, Eduardo Giménez, Hugo Herbelin and Patrick -Loiseleur. - -| Orsay, May 4th 1998 -| Christine Paulin -| - -Version 6.3 ------------ - -The main changes in version V6.3 were the introduction of a few new -tactics and the extension of the guard condition for fixpoint -definitions. - -B. Barras extended the unification algorithm to complete partial terms -and fixed various tricky bugs related to universes. - -D. Delahaye developed the ``AutoRewrite`` tactic. He also designed the -new behavior of ``Intro`` and provided the tacticals ``First`` and -``Solve``. - -J.-C. Filliâtre developed the ``Correctness`` tactic. - -\E. Giménez extended the guard condition in fixpoints. - -H. Herbelin designed the new syntax for definitions and extended the -``Induction`` tactic. - -P. Loiseleur developed the ``Quote`` tactic and the new design of the -``Auto`` tactic, he also introduced the index of errors in the -documentation. - -C. Paulin wrote the ``Focus`` command and introduced the reduction -functions in definitions, this last feature was proposed by J.-F. -Monin from CNET Lannion. - -| Orsay, Dec. 1999 -| Christine Paulin -| - -Versions 7 ----------- - -The version V7 is a new implementation started in September 1999 by -Jean-Christophe Filliâtre. This is a major revision with respect to the -internal architecture of the system. The |Coq| version 7.0 was distributed -in March 2001, version 7.1 in September 2001, version 7.2 in January -2002, version 7.3 in May 2002 and version 7.4 in February 2003. - -Jean-Christophe Filliâtre designed the architecture of the new system. -He introduced a new representation for environments and wrote a new -kernel for type checking terms. His approach was to use functional -data-structures in order to get more sharing, to prepare the addition of -modules and also to get closer to a certified kernel. - -Hugo Herbelin introduced a new structure of terms with local -definitions. He introduced “qualified” names, wrote a new -pattern matching compilation algorithm and designed a more compact -algorithm for checking the logical consistency of universes. He -contributed to the simplification of |Coq| internal structures and the -optimisation of the system. He added basic tactics for forward reasoning -and coercions in patterns. - -David Delahaye introduced a new language for tactics. General tactics -using pattern matching on goals and context can directly be written from -the |Coq| toplevel. He also provided primitives for the design of -user-defined tactics in Caml. - -Micaela Mayero contributed the library on real numbers. Olivier -Desmettre extended this library with axiomatic trigonometric functions, -square, square roots, finite sums, Chasles property and basic plane -geometry. - -Jean-Christophe Filliâtre and Pierre Letouzey redesigned a new -extraction procedure from |Coq| terms to Caml or Haskell programs. This -new extraction procedure, unlike the one implemented in previous version -of |Coq| is able to handle all terms in the Calculus of Inductive -Constructions, even involving universes and strong elimination. P. -Letouzey adapted user contributions to extract ML programs when it was -sensible. Jean-Christophe Filliâtre wrote ``coqdoc``, a documentation -tool for |Coq| libraries usable from version 7.2. - -Bruno Barras improved the efficiency of the reduction algorithm and the -confidence level in the correctness of |Coq| critical type checking -algorithm. - -Yves Bertot designed the ``SearchPattern`` and ``SearchRewrite`` tools -and the support for the pcoq interface -(http://www-sop.inria.fr/lemme/pcoq/). - -Micaela Mayero and David Delahaye introduced Field, a decision tactic -for commutative fields. - -Christine Paulin changed the elimination rules for empty and singleton -propositional inductive types. - -Loïc Pottier developed Fourier, a tactic solving linear inequalities on -real numbers. - -Pierre Crégut developed a new, reflection-based version of the Omega -decision procedure. - -Claudio Sacerdoti Coen designed an XML output for the |Coq| modules to be -used in the Hypertextual Electronic Library of Mathematics (HELM cf -http://www.cs.unibo.it/helm). - -A library for efficient representation of finite maps using binary trees -contributed by Jean Goubault was integrated in the basic theories. - -Pierre Courtieu developed a command and a tactic to reason on the -inductive structure of recursively defined functions. - -Jacek Chrząszcz designed and implemented the module system of |Coq| whose -foundations are in Judicaël Courant’s PhD thesis. - -The development was coordinated by C. Paulin. - -Many discussions within the Démons team and the LogiCal project -influenced significantly the design of |Coq| especially with J. Courant, -J. Duprat, J. Goubault, A. Miquel, C. Marché, B. Monate and B. Werner. - -Intensive users suggested improvements of the system : Y. Bertot, L. -Pottier, L. Théry, P. Zimmerman from INRIA, C. Alvarado, P. Crégut, -J.-F. Monin from France Telecom R & D. - -| Orsay, May. 2002 -| Hugo Herbelin & Christine Paulin -| - -Version 8.0 ------------ - -Coq version 8 is a major revision of the |Coq| proof assistant. First, the -underlying logic is slightly different. The so-called *impredicativity* -of the sort Set has been dropped. The main reason is that it is -inconsistent with the principle of description which is quite a useful -principle for formalizing mathematics within classical logic. Moreover, -even in an constructive setting, the impredicativity of Set does not add -so much in practice and is even subject of criticism from a large part -of the intuitionistic mathematician community. Nevertheless, the -impredicativity of Set remains optional for users interested in -investigating mathematical developments which rely on it. - -Secondly, the concrete syntax of terms has been completely revised. The -main motivations were - -- a more uniform, purified style: all constructions are now lowercase, - with a functional programming perfume (e.g. abstraction is now - written fun), and more directly accessible to the novice (e.g. - dependent product is now written forall and allows omission of - types). Also, parentheses are no longer mandatory for function - application. - -- extensibility: some standard notations (e.g. “<” and “>”) were - incompatible with the previous syntax. Now all standard arithmetic - notations (=, +, \*, /, <, <=, ... and more) are directly part of the - syntax. - -Together with the revision of the concrete syntax, a new mechanism of -*interpretation scopes* permits to reuse the same symbols (typically +, --, \*, /, <, <=) in various mathematical theories without any -ambiguities for |Coq|, leading to a largely improved readability of |Coq| -scripts. New commands to easily add new symbols are also provided. - -Coming with the new syntax of terms, a slight reform of the tactic -language and of the language of commands has been carried out. The -purpose here is a better uniformity making the tactics and commands -easier to use and to remember. - -Thirdly, a restructuring and uniformization of the standard library of -Coq has been performed. There is now just one Leibniz equality usable -for all the different kinds of |Coq| objects. Also, the set of real -numbers now lies at the same level as the sets of natural and integer -numbers. Finally, the names of the standard properties of numbers now -follow a standard pattern and the symbolic notations for the standard -definitions as well. - -The fourth point is the release of |CoqIDE|, a new graphical gtk2-based -interface fully integrated with |Coq|. Close in style to the Proof General -Emacs interface, it is faster and its integration with |Coq| makes -interactive developments more friendly. All mathematical Unicode symbols -are usable within |CoqIDE|. - -Finally, the module system of |Coq| completes the picture of |Coq| version -8.0. Though released with an experimental status in the previous version -7.4, it should be considered as a salient feature of the new version. - -Besides, |Coq| comes with its load of novelties and improvements: new or -improved tactics (including a new tactic for solving first-order -statements), new management commands, extended libraries. - -Bruno Barras and Hugo Herbelin have been the main contributors of the -reflection and the implementation of the new syntax. The smart automatic -translator from old to new syntax released with |Coq| is also their work -with contributions by Olivier Desmettre. - -Hugo Herbelin is the main designer and implementer of the notion of -interpretation scopes and of the commands for easily adding new -notations. - -Hugo Herbelin is the main implementer of the restructured standard library. - -Pierre Corbineau is the main designer and implementer of the new tactic -for solving first-order statements in presence of inductive types. He is -also the maintainer of the non-domain specific automation tactics. - -Benjamin Monate is the developer of the |CoqIDE| graphical interface with -contributions by Jean-Christophe Filliâtre, Pierre Letouzey, Claude -Marché and Bruno Barras. - -Claude Marché coordinated the edition of the Reference Manual for |Coq| -V8.0. - -Pierre Letouzey and Jacek Chrząszcz respectively maintained the -extraction tool and module system of |Coq|. - -Jean-Christophe Filliâtre, Pierre Letouzey, Hugo Herbelin and other -contributors from Sophia-Antipolis and Nijmegen participated in -extending the library. - -Julien Narboux built a NSIS-based automatic |Coq| installation tool for -the Windows platform. - -Hugo Herbelin and Christine Paulin coordinated the development which was -under the responsibility of Christine Paulin. - -| Palaiseau & Orsay, Apr. 2004 -| Hugo Herbelin & Christine Paulin -| (updated Apr. 2006) -| - -Version 8.1 ------------ - -Coq version 8.1 adds various new functionalities. - -Benjamin Grégoire implemented an alternative algorithm to check the -convertibility of terms in the |Coq| type checker. This alternative -algorithm works by compilation to an efficient bytecode that is -interpreted in an abstract machine similar to Xavier Leroy’s ZINC -machine. Convertibility is performed by comparing the normal forms. This -alternative algorithm is specifically interesting for proofs by -reflection. More generally, it is convenient in case of intensive -computations. - -Christine Paulin implemented an extension of inductive types allowing -recursively non uniform parameters. Hugo Herbelin implemented -sort-polymorphism for inductive types (now called template polymorphism). - -Claudio Sacerdoti Coen improved the tactics for rewriting on arbitrary -compatible equivalence relations. He also generalized rewriting to -arbitrary transition systems. - -Claudio Sacerdoti Coen added new features to the module system. - -Benjamin Grégoire, Assia Mahboubi and Bruno Barras developed a new, more -efficient and more general simplification algorithm for rings and -semirings. - -Laurent Théry and Bruno Barras developed a new, significantly more -efficient simplification algorithm for fields. - -Hugo Herbelin, Pierre Letouzey, Julien Forest, Julien Narboux and -Claudio Sacerdoti Coen added new tactic features. - -Hugo Herbelin implemented matching on disjunctive patterns. - -New mechanisms made easier the communication between |Coq| and external -provers. Nicolas Ayache and Jean-Christophe Filliâtre implemented -connections with the provers cvcl, Simplify and zenon. Hugo Herbelin -implemented an experimental protocol for calling external tools from the -tactic language. - -Matthieu Sozeau developed Russell, an experimental language to specify -the behavior of programs with subtypes. - -A mechanism to automatically use some specific tactic to solve -unresolved implicit has been implemented by Hugo Herbelin. - -Laurent Théry’s contribution on strings and Pierre Letouzey and -Jean-Christophe Filliâtre’s contribution on finite maps have been -integrated to the |Coq| standard library. Pierre Letouzey developed a -library about finite sets “à la Objective Caml”. With Jean-Marc Notin, -he extended the library on lists. Pierre Letouzey’s contribution on -rational numbers has been integrated and extended. - -Pierre Corbineau extended his tactic for solving first-order statements. -He wrote a reflection-based intuitionistic tautology solver. - -Pierre Courtieu, Julien Forest and Yves Bertot added extra support to -reason on the inductive structure of recursively defined functions. - -Jean-Marc Notin significantly contributed to the general maintenance of -the system. He also took care of ``coqdoc``. - -Pierre Castéran contributed to the documentation of (co-)inductive types -and suggested improvements to the libraries. - -Pierre Corbineau implemented a declarative mathematical proof language, -usable in combination with the tactic-based style of proof. - -Finally, many users suggested improvements of the system through the -Coq-Club mailing list and bug-tracker systems, especially user groups -from INRIA Rocquencourt, Radboud University, University of Pennsylvania -and Yale University. - -| Palaiseau, July 2006 -| Hugo Herbelin -| - -Version 8.2 ------------ - -Coq version 8.2 adds new features, new libraries and improves on many -various aspects. - -Regarding the language of |Coq|, the main novelty is the introduction by -Matthieu Sozeau of a package of commands providing Haskell-style typeclasses. -Typeclasses, which come with a few convenient features such as -type-based resolution of implicit arguments, play a new landmark role -in the architecture of |Coq| with respect to automation. For -instance, thanks to typeclass support, Matthieu Sozeau could -implement a new resolution-based version of the tactics dedicated to -rewriting on arbitrary transitive relations. - -Another major improvement of |Coq| 8.2 is the evolution of the arithmetic -libraries and of the tools associated to them. Benjamin Grégoire and -Laurent Théry contributed a modular library for building arbitrarily -large integers from bounded integers while Evgeny Makarov contributed a -modular library of abstract natural and integer arithmetic together -with a few convenient tactics. On his side, Pierre Letouzey made -numerous extensions to the arithmetic libraries on :math:`\mathbb{Z}` -and :math:`\mathbb{Q}`, including extra support for automation in -presence of various number-theory concepts. - -Frédéric Besson contributed a reflective tactic based on Krivine-Stengle -Positivstellensatz (the easy way) for validating provability of systems -of inequalities. The platform is flexible enough to support the -validation of any algorithm able to produce a “certificate” for the -Positivstellensatz and this covers the case of Fourier-Motzkin (for -linear systems in :math:`\mathbb{Q}` and :math:`\mathbb{R}`), -Fourier-Motzkin with cutting planes (for linear systems in -:math:`\mathbb{Z}`) and sum-of-squares (for non-linear systems). Evgeny -Makarov made the platform generic over arbitrary ordered rings. - -Arnaud Spiwack developed a library of 31-bits machine integers and, -relying on Benjamin Grégoire and Laurent Théry’s library, delivered a -library of unbounded integers in base :math:`2^{31}`. As importantly, he -developed a notion of “retro-knowledge” so as to safely extend the -kernel-located bytecode-based efficient evaluation algorithm of |Coq| -version 8.1 to use 31-bits machine arithmetic for efficiently computing -with the library of integers he developed. - -Beside the libraries, various improvements were contributed to provide a more -comfortable end-user language and more expressive tactic language. Hugo -Herbelin and Matthieu Sozeau improved the pattern matching compilation -algorithm (detection of impossible clauses in pattern matching, -automatic inference of the return type). Hugo Herbelin, Pierre Letouzey -and Matthieu Sozeau contributed various new convenient syntactic -constructs and new tactics or tactic features: more inference of -redundant information, better unification, better support for proof or -definition by fixpoint, more expressive rewriting tactics, better -support for meta-variables, more convenient notations... - -Élie Soubiran improved the module system, adding new features (such as -an “include” command) and making it more flexible and more general. He -and Pierre Letouzey improved the support for modules in the extraction -mechanism. - -Matthieu Sozeau extended the Russell language, ending in an convenient -way to write programs of given specifications, Pierre Corbineau extended -the Mathematical Proof Language and the automation tools that -accompany it, Pierre Letouzey supervised and extended various parts of the -standard library, Stéphane Glondu contributed a few tactics and -improvements, Jean-Marc Notin provided help in debugging, general -maintenance and coqdoc support, Vincent Siles contributed extensions of -the Scheme command and of injection. - -Bruno Barras implemented the ``coqchk`` tool: this is a stand-alone -type checker that can be used to certify .vo files. Especially, as this -verifier runs in a separate process, it is granted not to be “hijacked” -by virtually malicious extensions added to |Coq|. - -Yves Bertot, Jean-Christophe Filliâtre, Pierre Courtieu and Julien -Forest acted as maintainers of features they implemented in previous -versions of |Coq|. - -Julien Narboux contributed to |CoqIDE|. Nicolas Tabareau made the -adaptation of the interface of the old “setoid rewrite” tactic to the -new version. Lionel Mamane worked on the interaction between |Coq| and its -external interfaces. With Samuel Mimram, he also helped making |Coq| -compatible with recent software tools. Russell O’Connor, Cezary -Kaliszyk, Milad Niqui contributed to improve the libraries of integers, -rational, and real numbers. We also thank many users and partners for -suggestions and feedback, in particular Pierre Castéran and Arthur -Charguéraud, the INRIA Marelle team, Georges Gonthier and the -INRIA-Microsoft Mathematical Components team, the Foundations group at -Radboud university in Nijmegen, reporters of bugs and participants to -the Coq-Club mailing list. - -| Palaiseau, June 2008 -| Hugo Herbelin -| - -Version 8.3 ------------ - -Coq version 8.3 is before all a transition version with refinements or -extensions of the existing features and libraries and a new tactic nsatz -based on Hilbert’s Nullstellensatz for deciding systems of equations -over rings. - -With respect to libraries, the main evolutions are due to Pierre -Letouzey with a rewriting of the library of finite sets FSets and a new -round of evolutions in the modular development of arithmetic (library -Numbers). The reason for making FSets evolve is that the computational -and logical contents were quite intertwined in the original -implementation, leading in some cases to longer computations than -expected and this problem is solved in the new MSets implementation. As -for the modular arithmetic library, it was only dealing with the basic -arithmetic operators in the former version and its current extension -adds the standard theory of the division, min and max functions, all -made available for free to any implementation of :math:`\mathbb{N}`, -:math:`\mathbb{Z}` or :math:`\mathbb{Z}/n\mathbb{Z}`. - -The main other evolutions of the library are due to Hugo Herbelin who -made a revision of the sorting library (including a certified -merge-sort) and to Guillaume Melquiond who slightly revised and cleaned -up the library of reals. - -The module system evolved significantly. Besides the resolution of some -efficiency issues and a more flexible construction of module types, Élie -Soubiran brought a new model of name equivalence, the -:math:`\Delta`-equivalence, which respects as much as possible the names -given by the users. He also designed with Pierre Letouzey a new, -convenient operator ``<+`` for nesting functor application that -provides a light notation for inheriting the properties of cascading -modules. - -The new tactic nsatz is due to Loïc Pottier. It works by computing -Gröbner bases. Regarding the existing tactics, various improvements have -been done by Matthieu Sozeau, Hugo Herbelin and Pierre Letouzey. - -Matthieu Sozeau extended and refined the typeclasses and Program -features (the Russell language). Pierre Letouzey maintained and improved -the extraction mechanism. Bruno Barras and Élie Soubiran maintained the -Coq checker, Julien Forest maintained the Function mechanism for -reasoning over recursively defined functions. Matthieu Sozeau, Hugo -Herbelin and Jean-Marc Notin maintained coqdoc. Frédéric Besson -maintained the Micromega platform for deciding systems of inequalities. -Pierre Courtieu maintained the support for the Proof General Emacs -interface. Claude Marché maintained the plugin for calling external -provers (dp). Yves Bertot made some improvements to the libraries of -lists and integers. Matthias Puech improved the search functions. -Guillaume Melquiond usefully contributed here and there. Yann -Régis-Gianas grounded the support for Unicode on a more standard and -more robust basis. - -Though invisible from outside, Arnaud Spiwack improved the general -process of management of existential variables. Pierre Letouzey and -Stéphane Glondu improved the compilation scheme of the |Coq| archive. -Vincent Gross provided support to |CoqIDE|. Jean-Marc Notin provided -support for benchmarking and archiving. - -Many users helped by reporting problems, providing patches, suggesting -improvements or making useful comments, either on the bug tracker or on -the Coq-Club mailing list. This includes but not exhaustively Cédric -Auger, Arthur Charguéraud, François Garillot, Georges Gonthier, Robin -Green, Stéphane Lescuyer, Eelis van der Weegen, ... - -Though not directly related to the implementation, special thanks are -going to Yves Bertot, Pierre Castéran, Adam Chlipala, and Benjamin -Pierce for the excellent teaching materials they provided. - -| Paris, April 2010 -| Hugo Herbelin -| - -Version 8.4 ------------ - -Coq version 8.4 contains the result of three long-term projects: a new -modular library of arithmetic by Pierre Letouzey, a new proof engine by -Arnaud Spiwack and a new communication protocol for |CoqIDE| by Vincent -Gross. - -The new modular library of arithmetic extends, generalizes and unifies -the existing libraries on Peano arithmetic (types nat, N and BigN), -positive arithmetic (type positive), integer arithmetic (Z and BigZ) and -machine word arithmetic (type Int31). It provides with unified notations -(e.g. systematic use of add and mul for denoting the addition and -multiplication operators), systematic and generic development of -operators and properties of these operators for all the types mentioned -above, including gcd, pcm, power, square root, base 2 logarithm, -division, modulo, bitwise operations, logical shifts, comparisons, -iterators, ... - -The most visible feature of the new proof engine is the support for -structured scripts (bullets and proof brackets) but, even if yet not -user-available, the new engine also provides the basis for refining -existential variables using tactics, for applying tactics to several -goals simultaneously, for reordering goals, all features which are -planned for the next release. The new proof engine forced Pierre Letouzey -to reimplement info and Show Script differently. - -Before version 8.4, |CoqIDE| was linked to |Coq| with the graphical -interface living in a separate thread. From version 8.4, |CoqIDE| is a -separate process communicating with |Coq| through a textual channel. This -allows for a more robust interfacing, the ability to interrupt |Coq| -without interrupting the interface, and the ability to manage several -sessions in parallel. Relying on the infrastructure work made by Vincent -Gross, Pierre Letouzey, Pierre Boutillier and Pierre-Marie Pédrot -contributed many various refinements of |CoqIDE|. - -Coq 8.4 also comes with a bunch of various smaller-scale changes -and improvements regarding the different components of the system. - -The underlying logic has been extended with :math:`\eta`-conversion -thanks to Hugo Herbelin, Stéphane Glondu and Benjamin Grégoire. The -addition of :math:`\eta`-conversion is justified by the confidence that -the formulation of the Calculus of Inductive Constructions based on -typed equality (such as the one considered in Lee and Werner to build a -set-theoretic model of CIC :cite:`LeeWerner11`) is -applicable to the concrete implementation of |Coq|. - -The underlying logic benefited also from a refinement of the guard -condition for fixpoints by Pierre Boutillier, the point being that it is -safe to propagate the information about structurally smaller arguments -through :math:`\beta`-redexes that are blocked by the “match” -construction (blocked commutative cuts). - -Relying on the added permissiveness of the guard condition, Hugo -Herbelin could extend the pattern matching compilation algorithm so that -matching over a sequence of terms involving dependencies of a term or of -the indices of the type of a term in the type of other terms is -systematically supported. - -Regarding the high-level specification language, Pierre Boutillier -introduced the ability to give implicit arguments to anonymous -functions, Hugo Herbelin introduced the ability to define notations with -several binders (e.g. ``exists x y z, P``), Matthieu Sozeau made the -typeclass inference mechanism more robust and predictable, Enrico -Tassi introduced a command Arguments that generalizes Implicit Arguments -and Arguments Scope for assigning various properties to arguments of -constants. Various improvements in the type inference algorithm were -provided by Matthieu Sozeau and Hugo Herbelin with contributions from -Enrico Tassi. - -Regarding tactics, Hugo Herbelin introduced support for referring to -expressions occurring in the goal by pattern in tactics such as set or -destruct. Hugo Herbelin also relied on ideas from Chung-Kil Hur’s Heq -plugin to introduce automatic computation of occurrences to generalize -when using destruct and induction on types with indices. Stéphane Glondu -introduced new tactics :tacn:`constr_eq`, :tacn:`is_evar`, and :tacn:`has_evar`, to be used -when writing complex tactics. Enrico Tassi added support to fine-tuning -the behavior of :tacn:`simpl`. Enrico Tassi added the ability to specify over -which variables of a section a lemma has to be exactly generalized. -Pierre Letouzey added a tactic timeout and the interruptibility of -:tacn:`vm_compute`. Bug fixes and miscellaneous improvements of the tactic -language came from Hugo Herbelin, Pierre Letouzey and Matthieu Sozeau. - -Regarding decision tactics, Loïc Pottier maintained nsatz, moving in -particular to a typeclass based reification of goals while Frédéric -Besson maintained Micromega, adding in particular support for division. - -Regarding vernacular commands, Stéphane Glondu provided new commands to -analyze the structure of type universes. - -Regarding libraries, a new library about lists of a given length (called -vectors) has been provided by Pierre Boutillier. A new instance of -finite sets based on Red-Black trees and provided by Andrew Appel has -been adapted for the standard library by Pierre Letouzey. In the library -of real analysis, Yves Bertot changed the definition of :math:`\pi` and -provided a proof of the long-standing fact yet remaining unproved in -this library, namely that :math:`sin \frac{\pi}{2} = -1`. - -Pierre Corbineau maintained the Mathematical Proof Language (C-zar). - -Bruno Barras and Benjamin Grégoire maintained the call-by-value -reduction machines. - -The extraction mechanism benefited from several improvements provided by -Pierre Letouzey. - -Pierre Letouzey maintained the module system, with contributions from -Élie Soubiran. - -Julien Forest maintained the Function command. - -Matthieu Sozeau maintained the setoid rewriting mechanism. - -Coq related tools have been upgraded too. In particular, coq\_makefile -has been largely revised by Pierre Boutillier. Also, patches from Adam -Chlipala for coqdoc have been integrated by Pierre Boutillier. - -Bruno Barras and Pierre Letouzey maintained the `coqchk` checker. - -Pierre Courtieu and Arnaud Spiwack contributed new features for using -Coq through Proof General. - -The Dp plugin has been removed. Use the plugin provided with Why 3 -instead (http://why3.lri.fr/). - -Under the hood, the |Coq| architecture benefited from improvements in -terms of efficiency and robustness, especially regarding universes -management and existential variables management, thanks to Pierre -Letouzey and Yann Régis-Gianas with contributions from Stéphane Glondu -and Matthias Puech. The build system is maintained by Pierre Letouzey -with contributions from Stéphane Glondu and Pierre Boutillier. - -A new backtracking mechanism simplifying the task of external interfaces -has been designed by Pierre Letouzey. - -The general maintenance was done by Pierre Letouzey, Hugo Herbelin, -Pierre Boutillier, Matthieu Sozeau and Stéphane Glondu with also -specific contributions from Guillaume Melquiond, Julien Narboux and -Pierre-Marie Pédrot. - -Packaging tools were provided by Pierre Letouzey (Windows), Pierre -Boutillier (MacOS), Stéphane Glondu (Debian). Releasing, testing and -benchmarking support was provided by Jean-Marc Notin. - -Many suggestions for improvements were motivated by feedback from users, -on either the bug tracker or the Coq-Club mailing list. Special thanks -are going to the users who contributed patches, starting with Tom -Prince. Other patch contributors include Cédric Auger, David Baelde, Dan -Grayson, Paolo Herms, Robbert Krebbers, Marc Lasson, Hendrik Tews and -Eelis van der Weegen. - -| Paris, December 2011 -| Hugo Herbelin -| - -Version 8.5 ------------ - -Coq version 8.5 contains the result of five specific long-term projects: - -- A new asynchronous evaluation and compilation mode by Enrico Tassi - with help from Bruno Barras and Carst Tankink. - -- Full integration of the new proof engine by Arnaud Spiwack helped by - Pierre-Marie Pédrot, - -- Addition of conversion and reduction based on native compilation by - Maxime Dénès and Benjamin Grégoire. - -- Full universe polymorphism for definitions and inductive types by - Matthieu Sozeau. - -- An implementation of primitive projections with - :math:`\eta`\-conversion bringing significant performance improvements - when using records by Matthieu Sozeau. - -The full integration of the proof engine, by Arnaud Spiwack and -Pierre-Marie Pédrot, brings to primitive tactics and the user level Ltac -language dependent subgoals, deep backtracking and multiple goal -handling, along with miscellaneous features and an improved potential -for future modifications. Dependent subgoals allow statements in a goal -to mention the proof of another. Proofs of unsolved subgoals appear as -existential variables. Primitive backtracking makes it possible to write -a tactic with several possible outcomes which are tried successively -when subsequent tactics fail. Primitives are also available to control -the backtracking behavior of tactics. Multiple goal handling paves the -way for smarter automation tactics. It is currently used for simple goal -manipulation such as goal reordering. - -The way |Coq| processes a document in batch and interactive mode has been -redesigned by Enrico Tassi with help from Bruno Barras. Opaque proofs, -the text between Proof and Qed, can be processed asynchronously, -decoupling the checking of definitions and statements from the checking -of proofs. It improves the responsiveness of interactive development, -since proofs can be processed in the background. Similarly, compilation -of a file can be split into two phases: the first one checking only -definitions and statements and the second one checking proofs. A file -resulting from the first phase – with the .vio extension – can be -already Required. All .vio files can be turned into complete .vo files -in parallel. The same infrastructure also allows terminating tactics to -be run in parallel on a set of goals via the ``par:`` goal selector. - -|CoqIDE| was modified to cope with asynchronous checking of the document. -Its source code was also made separate from that of |Coq|, so that |CoqIDE| -no longer has a special status among user interfaces, paving the way for -decoupling its release cycle from that of |Coq| in the future. - -Carst Tankink developed a |Coq| back-end for user interfaces built on -Makarius Wenzel’s Prover IDE framework (PIDE), like PIDE/jEdit (with -help from Makarius Wenzel) or PIDE/Coqoon (with help from Alexander -Faithfull and Jesper Bengtson). The development of such features was -funded by the Paral-ITP French ANR project. - -The full universe polymorphism extension was designed by Matthieu -Sozeau. It conservatively extends the universes system and core calculus -with definitions and inductive declarations parameterized by universes -and constraints. It is based on a modification of the kernel -architecture to handle constraint checking only, leaving the generation -of constraints to the refinement/type inference engine. Accordingly, -tactics are now fully universe aware, resulting in more localized error -messages in case of inconsistencies and allowing higher-level algorithms -like unification to be entirely type safe. The internal representation -of universes has been modified but this is invisible to the user. - -The underlying logic has been extended with :math:`\eta`\-conversion for -records defined with primitive projections by Matthieu Sozeau. This -additional form of :math:`\eta`\-conversion is justified using the same -principle than the previously added :math:`\eta`\-conversion for function -types, based on formulations of the Calculus of Inductive Constructions -with typed equality. Primitive projections, which do not carry the -parameters of the record and are rigid names (not defined as a -pattern matching construct), make working with nested records more -manageable in terms of time and space consumption. This extension and -universe polymorphism were carried out partly while Matthieu Sozeau was -working at the IAS in Princeton. - -The guard condition has been made compliant with extensional equality -principles such as propositional extensionality and univalence, thanks -to Maxime Dénès and Bruno Barras. To ensure compatibility with the -univalence axiom, a new flag ``-indices-matter`` has been implemented, -taking into account the universe levels of indices when computing the -levels of inductive types. This supports using |Coq| as a tool to explore -the relations between homotopy theory and type theory. - -Maxime Dénès and Benjamin Grégoire developed an implementation of -conversion test and normal form computation using the OCaml native -compiler. It complements the virtual machine conversion offering much -faster computation for expensive functions. - -Coq 8.5 also comes with a bunch of many various smaller-scale changes -and improvements regarding the different components of the system. We -shall only list a few of them. - -Pierre Boutillier developed an improved tactic for simplification of -expressions called :tacn:`cbn`. - -Maxime Dénès maintained the bytecode-based reduction machine. Pierre -Letouzey maintained the extraction mechanism. - -Pierre-Marie Pédrot has extended the syntax of terms to, experimentally, -allow holes in terms to be solved by a locally specified tactic. - -Existential variables are referred to by identifiers rather than mere -numbers, thanks to Hugo Herbelin who also improved the tactic language -here and there. - -Error messages for universe inconsistencies have been improved by -Matthieu Sozeau. Error messages for unification and type inference -failures have been improved by Hugo Herbelin, Pierre-Marie Pédrot and -Arnaud Spiwack. - -Pierre Courtieu contributed new features for using |Coq| through Proof -General and for better interactive experience (bullets, Search, etc). - -The efficiency of the whole system has been significantly improved -thanks to contributions from Pierre-Marie Pédrot. - -A distribution channel for |Coq| packages using the OPAM tool has been -initiated by Thomas Braibant and developed by Guillaume Claret, with -contributions by Enrico Tassi and feedback from Hugo Herbelin. - -Packaging tools were provided by Pierre Letouzey and Enrico Tassi -(Windows), Pierre Boutillier, Matthieu Sozeau and Maxime Dénès (MacOS -X). Maxime Dénès improved significantly the testing and benchmarking -support. - -Many power users helped to improve the design of the new features via -the bug tracker, the coq development mailing list or the Coq-Club -mailing list. Special thanks are going to the users who contributed -patches and intensive brain-storming, starting with Jason Gross, -Jonathan Leivent, Greg Malecha, Clément Pit-Claudel, Marc Lasson, Lionel -Rieg. It would however be impossible to mention with precision all names -of people who to some extent influenced the development. - -Version 8.5 is one of the most important releases of |Coq|. Its development -spanned over about 3 years and a half with about one year of -beta-testing. General maintenance during part or whole of this period -has been done by Pierre Boutillier, Pierre Courtieu, Maxime Dénès, Hugo -Herbelin, Pierre Letouzey, Guillaume Melquiond, Pierre-Marie Pédrot, -Matthieu Sozeau, Arnaud Spiwack, Enrico Tassi as well as Bruno Barras, -Yves Bertot, Frédéric Besson, Xavier Clerc, Pierre Corbineau, -Jean-Christophe Filliâtre, Julien Forest, Sébastien Hinderer, Assia -Mahboubi, Jean-Marc Notin, Yann Régis-Gianas, François Ripault, Carst -Tankink. Maxime Dénès coordinated the release process. - -| Paris, January 2015, revised December 2015, -| Hugo Herbelin, Matthieu Sozeau and the |Coq| development team -| - -Version 8.6 ------------ - -Coq version 8.6 contains the result of refinements, stabilization of -8.5’s features and cleanups of the internals of the system. Over the -year of (now time-based) development, about 450 bugs were resolved and -over 100 contributions integrated. The main user visible changes are: - -- A new, faster state-of-the-art universe constraint checker, by - Jacques-Henri Jourdan. - -- In |CoqIDE| and other asynchronous interfaces, more fine-grained - asynchronous processing and error reporting by Enrico Tassi, making - |Coq| capable of recovering from errors and continue processing the - document. - -- More access to the proof engine features from Ltac: goal management - primitives, range selectors and a :tacn:`typeclasses eauto` engine handling - multiple goals and multiple successes, by Cyprien Mangin, Matthieu - Sozeau and Arnaud Spiwack. - -- Tactic behavior uniformization and specification, generalization of - intro-patterns by Hugo Herbelin and others. - -- A brand new warning system allowing to control warnings, turn them - into errors or ignore them selectively by Maxime Dénès, Guillaume - Melquiond, Pierre-Marie Pédrot and others. - -- Irrefutable patterns in abstractions, by Daniel de Rauglaudre. - -- The ssreflect subterm selection algorithm by Georges Gonthier and - Enrico Tassi is now accessible to tactic writers through the - ssrmatching plugin. - -- Integration of LtacProf, a profiler for Ltac by Jason Gross, Paul - Steckler, Enrico Tassi and Tobias Tebbi. - -Coq 8.6 also comes with a bunch of smaller-scale changes and -improvements regarding the different components of the system. We shall -only list a few of them. - -The iota reduction flag is now a shorthand for match, fix and cofix -flags controlling the corresponding reduction rules (by Hugo Herbelin -and Maxime Dénès). - -Maxime Dénès maintained the native compilation machinery. - -Pierre-Marie Pédrot separated the Ltac code from general purpose -tactics, and generalized and rationalized the handling of generic -arguments, allowing to create new versions of Ltac more easily in the -future. - -In patterns and terms, @, abbreviations and notations are now -interpreted the same way, by Hugo Herbelin. - -Name handling for universes has been improved by Pierre-Marie Pédrot and -Matthieu Sozeau. The minimization algorithm has been improved by -Matthieu Sozeau. - -The unifier has been improved by Hugo Herbelin and Matthieu Sozeau, -fixing some incompatibilities introduced in |Coq| 8.5. Unification -constraints can now be left floating around and be seen by the user -thanks to a new option. The Keyed Unification mode has been improved by -Matthieu Sozeau. - -The typeclass resolution engine and associated proof-search tactic have -been reimplemented on top of the proof-engine monad, providing better -integration in tactics, and new options have been introduced to control -it, by Matthieu Sozeau with help from Théo Zimmermann. - -The efficiency of the whole system has been significantly improved -thanks to contributions from Pierre-Marie Pédrot, Maxime Dénès and -Matthieu Sozeau and performance issue tracking by Jason Gross and Paul -Steckler. - -Standard library improvements by Jason Gross, Sébastien Hinderer, Pierre -Letouzey and others. - -Emilio Jesús Gallego Arias contributed many cleanups and refactorings of -the pretty-printing and user interface communication components. - -Frédéric Besson maintained the micromega tactic. - -The OPAM repository for |Coq| packages has been maintained by Guillaume -Claret, Guillaume Melquiond, Matthieu Sozeau, Enrico Tassi and others. A -list of packages is now available at https://coq.inria.fr/opam/www/. - -Packaging tools and software development kits were prepared by Michael -Soegtrop with the help of Maxime Dénès and Enrico Tassi for Windows, and -Maxime Dénès and Matthieu Sozeau for MacOS X. Packages are now regularly -built on the continuous integration server. |Coq| now comes with a META -file usable with ocamlfind, contributed by Emilio Jesús Gallego Arias, -Gregory Malecha, and Matthieu Sozeau. - -Matej Košík maintained and greatly improved the continuous integration -setup and the testing of |Coq| contributions. He also contributed many API -improvements and code cleanups throughout the system. - -The contributors for this version are Bruno Barras, C.J. Bell, Yves -Bertot, Frédéric Besson, Pierre Boutillier, Tej Chajed, Guillaume -Claret, Xavier Clerc, Pierre Corbineau, Pierre Courtieu, Maxime Dénès, -Ricky Elrod, Emilio Jesús Gallego Arias, Jason Gross, Hugo Herbelin, -Sébastien Hinderer, Jacques-Henri Jourdan, Matej Košík, Xavier Leroy, -Pierre Letouzey, Gregory Malecha, Cyprien Mangin, Erik Martin-Dorel, -Guillaume Melquiond, Clément Pit–Claudel, Pierre-Marie Pédrot, Daniel de -Rauglaudre, Lionel Rieg, Gabriel Scherer, Thomas Sibut-Pinote, Matthieu -Sozeau, Arnaud Spiwack, Paul Steckler, Enrico Tassi, Laurent Théry, -Nickolai Zeldovich and Théo Zimmermann. The development process was -coordinated by Hugo Herbelin and Matthieu Sozeau with the help of Maxime -Dénès, who was also in charge of the release process. - -Many power users helped to improve the design of the new features via -the bug tracker, the pull request system, the |Coq| development mailing -list or the Coq-Club mailing list. Special thanks to the users who -contributed patches and intensive brain-storming and code reviews, -starting with Cyril Cohen, Jason Gross, Robbert Krebbers, Jonathan -Leivent, Xavier Leroy, Gregory Malecha, Clément Pit–Claudel, Gabriel -Scherer and Beta Ziliani. It would however be impossible to mention -exhaustively the names of everybody who to some extent influenced the -development. - -Version 8.6 is the first release of |Coq| developed on a time-based -development cycle. Its development spanned 10 months from the release of -Coq 8.5 and was based on a public roadmap. To date, it contains more -external contributions than any previous |Coq| system. Code reviews were -systematically done before integration of new features, with an -important focus given to compatibility and performance issues, resulting -in a hopefully more robust release than |Coq| 8.5. - -Coq Enhancement Proposals (CEPs for short) were introduced by Enrico -Tassi to provide more visibility and a discussion period on new -features, they are publicly available https://github.com/coq/ceps. - -Started during this period, an effort is led by Yves Bertot and Maxime -Dénès to put together a |Coq| consortium. - -| Paris, November 2016, -| Matthieu Sozeau and the |Coq| development team -| - -Version 8.7 ------------ - -|Coq| version 8.7 contains the result of refinements, stabilization of features -and cleanups of the internals of the system along with a few new features. The -main user visible changes are: - -- New tactics: variants of tactics supporting existential variables :tacn:`eassert`, - :tacn:`eenough`, etc... by Hugo Herbelin. Tactics ``extensionality in H`` and - :tacn:`inversion_sigma` by Jason Gross, ``specialize with ...`` accepting partial bindings - by Pierre Courtieu. - -- ``Cumulative Polymorphic Inductive`` types, allowing cumulativity of universes to - go through applied inductive types, by Amin Timany and Matthieu Sozeau. - -- Integration of the SSReflect plugin and its documentation in the reference - manual, by Enrico Tassi, Assia Mahboubi and Maxime Dénès. - -- The ``coq_makefile`` tool was completely redesigned to improve its maintainability - and the extensibility of generated Makefiles, and to make ``_CoqProject`` files - more palatable to IDEs by Enrico Tassi. - -|Coq| 8.7 involved a large amount of work on cleaning and speeding up the code -base, notably the work of Pierre-Marie Pédrot on making the tactic-level system -insensitive to existential variable expansion, providing a safer API to plugin -writers and making the code more robust. The ``dev/doc/changes.txt`` file -documents the numerous changes to the implementation and improvements of -interfaces. An effort to provide an official, streamlined API to plugin writers -is in progress, thanks to the work of Matej Košík. - -Version 8.7 also comes with a bunch of smaller-scale changes and improvements -regarding the different components of the system. We shall only list a few of -them. - -The efficiency of the whole system has been significantly improved thanks to -contributions from Pierre-Marie Pédrot, Maxime Dénès and Matthieu Sozeau and -performance issue tracking by Jason Gross and Paul Steckler. - -Thomas Sibut-Pinote and Hugo Herbelin added support for side effect hooks in -cbv, cbn and simpl. The side effects are provided via a plugin available at -https://github.com/herbelin/reduction-effects/. - -The BigN, BigZ, BigQ libraries are no longer part of the |Coq| standard library, -they are now provided by a separate repository https://github.com/coq/bignums, -maintained by Pierre Letouzey. - -In the Reals library, ``IZR`` has been changed to produce a compact representation -of integers and real constants are now represented using ``IZR`` (work by -Guillaume Melquiond). - -Standard library additions and improvements by Jason Gross, Pierre Letouzey and -others, documented in the ``CHANGES.md`` file. - -The mathematical proof language/declarative mode plugin was removed from the -archive. - -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/. - -Packaging tools and software development kits were prepared by Michael Soegtrop -with the help of Maxime Dénès and Enrico Tassi for Windows, and Maxime Dénès for -MacOS X. Packages are regularly built on the Travis continuous integration -server. - -The contributors for this version are Abhishek Anand, C.J. Bell, Yves Bertot, -Frédéric Besson, Tej Chajed, Pierre Courtieu, Maxime Dénès, Julien Forest, -Gaëtan Gilbert, Jason Gross, Hugo Herbelin, Emilio Jesús Gallego Arias, Ralf -Jung, Matej Košík, Xavier Leroy, Pierre Letouzey, Assia Mahboubi, Cyprien -Mangin, Erik Martin-Dorel, Olivier Marty, Guillaume Melquiond, Sam Pablo Kuper, -Benjamin Pierce, Pierre-Marie Pédrot, Lars Rasmusson, Lionel Rieg, Valentin -Robert, Yann Régis-Gianas, Thomas Sibut-Pinote, Michael Soegtrop, Matthieu -Sozeau, Arnaud Spiwack, Paul Steckler, George Stelle, Pierre-Yves Strub, Enrico -Tassi, Hendrik Tews, Amin Timany, Laurent Théry, Vadim Zaliva and Théo -Zimmermann. - -The development process was coordinated by Matthieu Sozeau with the help of -Maxime Dénès, who was also in charge of the release process. Théo Zimmermann is -the maintainer of this release. - -Many power users helped to improve the design of the new features via the bug -tracker, the pull request system, the |Coq| development mailing list or the -Coq-Club mailing list. Special thanks to the users who contributed patches and -intensive brain-storming and code reviews, starting with Jason Gross, Ralf Jung, -Robbert Krebbers, Xavier Leroy, Clément Pit–Claudel and Gabriel Scherer. It -would however be impossible to mention exhaustively the names of everybody who -to some extent influenced the development. - -Version 8.7 is the second release of |Coq| developed on a time-based development -cycle. Its development spanned 9 months from the release of |Coq| 8.6 and was -based on a public road-map. It attracted many external contributions. Code -reviews and continuous integration testing were systematically used before -integration of new features, with an important focus given to compatibility and -performance issues, resulting in a hopefully more robust release than |Coq| 8.6 -while maintaining compatibility. - -|Coq| Enhancement Proposals (CEPs for short) and open pull request discussions -were used to discuss publicly the new features. - -The |Coq| consortium, an organization directed towards users and supporters of the -system, is now upcoming and will rely on Inria’s newly created Foundation. - -| Paris, August 2017, -| Matthieu Sozeau and the |Coq| development team -| - -Version 8.8 ------------ - -|Coq| version 8.8 contains the result of refinements and stabilization of -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, 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. - -- Proof language: tacticals for profiling, timing and checking success - or failure of tactics by Jason Gross. The focusing bracket ``{`` - supports single-numbered goal selectors, e.g. ``2:{``, by Théo - Zimmermann. - -- Vernacular: deprecation of commands and more uniform handling of the - ``Local`` flag, by Vincent Laporte and Maxime Dénès, part of a larger - attribute system overhaul. Experimental ``Show Extraction`` command by - Pierre Letouzey. Coercion now accepts ``Prop`` or ``Type`` as a source - by Arthur Charguéraud. ``Export`` modifier for options allowing to - export the option to modules that ``Import`` and not only ``Require`` - a module, by Pierre-Marie Pédrot. - -- Universes: many user-level and API level enhancements: qualified - naming and printing, variance annotations for cumulative inductive - types, more general constraints and enhancements of the minimization - heuristics, interaction with modules by Gaëtan Gilbert, Pierre-Marie - Pédrot and Matthieu Sozeau. - -- Library: Decimal Numbers library by Pierre Letouzey and various small - improvements. - -- Documentation: a large community effort resulted in the migration - of the reference manual to the Sphinx documentation tool. The result - 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. - -On the implementation side, the ``dev/doc/changes.md`` file -documents the numerous changes to the implementation and improvements of -interfaces. The file provides guidelines on porting a plugin to the new -version. - -Version 8.8 also comes with a bunch of smaller-scale changes and -improvements regarding the different components of the system. -Most important ones are documented in the ``CHANGES.md`` file. - -The efficiency of the whole system has seen improvements thanks to -contributions from Gaëtan Gilbert, Pierre-Marie Pédrot, Maxime Dénès and -Matthieu Sozeau and performance issue tracking by Jason Gross and Paul -Steckler. - -The official wiki and the bugtracker of |Coq| migrated to the GitHub -platform, thanks to the work of Pierre Letouzey and Théo -Zimmermann. Gaëtan Gilbert, Emilio Jesús Gallego Arias worked on -maintaining and improving the continuous integration system. - -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 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 -|Coq| 8.7 and was based on a public roadmap. The development process -was coordinated by Matthieu Sozeau. Maxime Dénès was in charge of the -release process. Théo Zimmermann is the maintainer of this release. - -Many power users helped to improve the design of the new features via -the bug tracker, the pull request system, the |Coq| development mailing -list or the coq-club@inria.fr mailing list. Special thanks to the users who -contributed patches and intensive brain-storming and code reviews, -starting with Jason Gross, Ralf Jung, Robbert Krebbers and Amin Timany. -It would however be impossible to mention exhaustively the names -of everybody who to some extent influenced the development. - -The |Coq| consortium, an organization directed towards users and -supporters of the system, is now running and employs Maxime Dénès. -The contacts of the Coq Consortium are Yves Bertot and Maxime Dénès. - -| Santiago de Chile, March 2018, -| Matthieu Sozeau for the |Coq| development team -| - -Version 8.9 ------------ - -|Coq| version 8.9 contains the result of refinements and stabilization -of features and deprecations or removals of deprecated features, -cleanups of the internals of the system and API along with a few new -features. This release includes many user-visible changes, including -deprecations that are documented in ``CHANGES.md`` and new features that -are documented in the reference manual. Here are the most important -changes: - -- Kernel: mutually recursive records are now supported, by Pierre-Marie - Pédrot. - -- Notations: - - - Support for autonomous grammars of terms called “custom entries”, by - Hugo Herbelin (see Section :ref:`custom-entries` of the reference - manual). - - - Deprecated notations of the standard library will be removed in the - next version of |Coq|, see the ``CHANGES.md`` file for a script to - ease porting, by Jason Gross and Jean-Christophe Léchenet. - - - Added the :cmd:`Numeral Notation` command for registering decimal - numeral notations for custom types, by Daniel de Rauglaudre, Pierre - Letouzey and Jason Gross. - -- Tactics: Introduction tactics :tacn:`intro`/:tacn:`intros` on a goal that is an - existential variable now force a refinement of the goal into a - dependent product rather than failing, by Hugo Herbelin. - -- Decision procedures: deprecation of tactic ``romega`` in favor of - :tacn:`lia` and removal of ``fourier``, replaced by :tacn:`lra` which - subsumes it, by Frédéric Besson, Maxime Dénès, Vincent Laporte and - Laurent Théry. - -- Proof language: focusing bracket ``{`` now supports named - :ref:`goals <curly-braces>`, e.g. ``[x]:{`` will focus - on a goal (existential variable) named ``x``, by Théo Zimmermann. - -- SSReflect: the implementation of delayed clear was simplified by - Enrico Tassi: the variables are always renamed using inaccessible - names when the clear switch is processed and finally cleared at the - end of the intro pattern. In addition to that, the use-and-discard flag - ``{}`` typical of rewrite rules can now be also applied to views, - e.g. ``=> {}/v`` applies ``v`` and then clears ``v``. See Section - :ref:`introduction_ssr`. - -- Vernacular: - - - Experimental support for :ref:`attributes <gallina-attributes>` on - commands, by Vincent Laporte, as in ``#[local] Lemma foo : bar.`` - Tactics and tactic notations now support the ``deprecated`` - attribute. - - - Removed deprecated commands ``Arguments Scope`` and ``Implicit - Arguments`` in favor of :cmd:`Arguments`, with the help of Jasper - Hugunin. - - - New flag :flag:`Uniform Inductive Parameters` by Jasper Hugunin to - avoid repeating uniform parameters in constructor declarations. - - - New commands :cmd:`Hint Variables` and :cmd:`Hint Constants`, by - Matthieu Sozeau, for controlling the opacity status of variables and - constants in hint databases. It is recommended to always use these - commands after creating a hint databse with :cmd:`Create HintDb`. - - - Multiple sections with the same name are now allowed, by Jasper - Hugunin. - -- Library: additions and changes in the ``VectorDef``, ``Ascii``, and - ``String`` libraries. Syntax notations are now available only when using - ``Import`` of libraries and not merely ``Require``, by various - contributors (source of incompatibility, see ``CHANGES.md`` for details). - -- Toplevels: ``coqtop`` and ``coqide`` can now display diffs between proof - steps in color, using the :opt:`Diffs` option, by Jim Fehrle. - -- Documentation: we integrated a large number of fixes to the new Sphinx - documentation by various contributors, coordinated by Clément - Pit-Claudel and Théo Zimmermann. - -- Tools: removed the ``gallina`` utility and the homebrewed ``Emacs`` mode. - -- Packaging: as in |Coq| 8.8.2, the Windows installer now includes many - more external packages that can be individually selected for - installation, by Michael Soegtrop. - -Version 8.9 also comes with a bunch of smaller-scale changes and -improvements regarding the different components of the system. Most -important ones are documented in the ``CHANGES.md`` file. - -On the implementation side, the ``dev/doc/changes.md`` file documents -the numerous changes to the implementation and improvements of -interfaces. The file provides guidelines on porting a plugin to the new -version and a plugin development tutorial kept in sync with Coq was -introduced by Yves Bertot http://github.com/ybertot/plugin_tutorials. -The new ``dev/doc/critical-bugs`` file documents the known critical bugs -of |Coq| and affected releases. - -The efficiency of the whole system has seen improvements thanks to -contributions from Gaëtan Gilbert, Pierre-Marie Pédrot, and Maxime Dénès. - -Maxime Dénès, Emilio Jesús Gallego Arias, Gaëtan Gilbert, Michael -Soegtrop, Théo Zimmermann worked on maintaining and improving the -continuous integration system. - -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 54 contributors for this version are Léo Andrès, Rin Arakaki, -Benjamin Barenblat, Langston Barrett, Siddharth Bhat, Martin Bodin, -Simon Boulier, Timothy Bourke, Joachim Breitner, Tej Chajed, Arthur -Charguéraud, Pierre Courtieu, Maxime Dénès, Andres Erbsen, Jim Fehrle, -Julien Forest, Emilio Jesus Gallego Arias, Gaëtan Gilbert, Matěj -Grabovský, Jason Gross, Samuel Gruetter, Armaël Guéneau, Hugo Herbelin, -Jasper Hugunin, Ralf Jung, Sam Pablo Kuper, Ambroise Lafont, Leonidas -Lampropoulos, Vincent Laporte, Peter LeFanu Lumsdaine, Pierre Letouzey, -Jean-Christophe Léchenet, Nick Lewycky, Yishuai Li, Sven M. Hallberg, -Assia Mahboubi, Cyprien Mangin, Guillaume Melquiond, Perry E. Metzger, -Clément Pit-Claudel, Pierre-Marie Pédrot, Daniel R. Grayson, Kazuhiko -Sakaguchi, Michael Soegtrop, Matthieu Sozeau, Paul Steckler, Enrico -Tassi, Laurent Théry, Anton Trunov, whitequark, Théo Winterhalter, -Zeimer, Beta Ziliani, Théo Zimmermann. - -Many power users helped to improve the design of the new features via -the issue and pull request system, the |Coq| development mailing list or -the coq-club@inria.fr mailing list. It would be impossible to mention -exhaustively the names of everybody who to some extent influenced the -development. - -Version 8.9 is the fourth release of |Coq| developed on a time-based -development cycle. Its development spanned 7 months from the release of -|Coq| 8.8. The development moved to a decentralized merging process -during this cycle. Guillaume Melquiond was in charge of the release -process and is the maintainer of this release. This release is the -result of ~2,000 commits and ~500 PRs merged, closing 75+ issues. - -The |Coq| development team welcomed Vincent Laporte, a new |Coq| -engineer working with Maxime Dénès in the |Coq| consortium. - -| Paris, November 2018, -| Matthieu Sozeau for the |Coq| development team -| diff --git a/doc/sphinx/history.rst b/doc/sphinx/history.rst new file mode 100644 index 0000000000..0f5b991ba4 --- /dev/null +++ b/doc/sphinx/history.rst @@ -0,0 +1,1449 @@ +-------------------- +Early history of Coq +-------------------- + +Historical roots +---------------- + +Coq is a proof assistant for higher-order logic, allowing the +development of computer programs consistent with their formal +specification. It is the result of about ten years [#years]_ of research +of the Coq project. We shall briefly survey here three main aspects: the +*logical language* in which we write our axiomatizations and +specifications, the *proof assistant* which allows the development of +verified mathematical proofs, and the *program extractor* which +synthesizes computer programs obeying their formal specifications, +written as logical assertions in the language. + +The logical language used by |Coq| is a variety of type theory, called the +*Calculus of Inductive Constructions*. Without going back to Leibniz and +Boole, we can date the creation of what is now called mathematical logic +to the work of Frege and Peano at the turn of the century. The discovery +of antinomies in the free use of predicates or comprehension principles +prompted Russell to restrict predicate calculus with a stratification of +*types*. This effort culminated with *Principia Mathematica*, the first +systematic attempt at a formal foundation of mathematics. A +simplification of this system along the lines of simply typed +λ-calculus occurred with Church’s *Simple Theory of +Types*. The λ-calculus notation, originally used for +expressing functionality, could also be used as an encoding of natural +deduction proofs. This Curry-Howard isomorphism was used by N. de Bruijn +in the *Automath* project, the first full-scale attempt to develop and +mechanically verify mathematical proofs. This effort culminated with +Jutting’s verification of Landau’s *Grundlagen* in the 1970’s. +Exploiting this Curry-Howard isomorphism, notable achievements in proof +theory saw the emergence of two type-theoretic frameworks; the first +one, Martin-Löf’s *Intuitionistic Theory of Types*, attempts a new +foundation of mathematics on constructive principles. The second one, +Girard’s polymorphic λ-calculus :math:`F_\omega`, is a +very strong functional system in which we may represent higher-order +logic proof structures. Combining both systems in a higher-order +extension of the Automath language, T. Coquand presented in 1985 the +first version of the *Calculus of Constructions*, CoC. This strong +logical system allowed powerful axiomatizations, but direct inductive +definitions were not possible, and inductive notions had to be defined +indirectly through functional encodings, which introduced inefficiencies +and awkwardness. The formalism was extended in 1989 by T. Coquand and C. +Paulin with primitive inductive definitions, leading to the current +*Calculus of Inductive Constructions*. This extended formalism is not +rigorously defined here. Rather, numerous concrete examples are +discussed. We refer the interested reader to relevant research papers +for more information about the formalism, its meta-theoretic properties, +and semantics. However, it should not be necessary to understand this +theoretical material in order to write specifications. It is possible to +understand the Calculus of Inductive Constructions at a higher level, as +a mixture of predicate calculus, inductive predicate definitions +presented as typed PROLOG, and recursive function definitions close to +the language ML. + +Automated theorem-proving was pioneered in the 1960’s by Davis and +Putnam in propositional calculus. A complete mechanization (in the sense +of a semidecision procedure) of classical first-order logic was +proposed in 1965 by J.A. Robinson, with a single uniform inference rule +called *resolution*. Resolution relies on solving equations in free +algebras (i.e. term structures), using the *unification algorithm*. Many +refinements of resolution were studied in the 1970’s, but few convincing +implementations were realized, except of course that PROLOG is in some +sense issued from this effort. A less ambitious approach to proof +development is computer-aided proof-checking. The most notable +proof-checkers developed in the 1970’s were LCF, designed by R. Milner +and his colleagues at U. Edinburgh, specialized in proving properties +about denotational semantics recursion equations, and the Boyer and +Moore theorem-prover, an automation of primitive recursion over +inductive data types. While the Boyer-Moore theorem-prover attempted to +synthesize proofs by a combination of automated methods, LCF constructed +its proofs through the programming of *tactics*, written in a high-level +functional meta-language, ML. + +The salient feature which clearly distinguishes our proof assistant from +say LCF or Boyer and Moore’s, is its possibility to extract programs +from the constructive contents of proofs. This computational +interpretation of proof objects, in the tradition of Bishop’s +constructive mathematics, is based on a realizability interpretation, in +the sense of Kleene, due to C. Paulin. The user must just mark his +intention by separating in the logical statements the assertions stating +the existence of a computational object from the logical assertions +which specify its properties, but which may be considered as just +comments in the corresponding program. Given this information, the +system automatically extracts a functional term from a consistency proof +of its specifications. This functional term may be in turn compiled into +an actual computer program. This methodology of extracting programs from +proofs is a revolutionary paradigm for software engineering. Program +synthesis has long been a theme of research in artificial intelligence, +pioneered by R. Waldinger. The Tablog system of Z. Manna and R. +Waldinger allows the deductive synthesis of functional programs from +proofs in tableau form of their specifications, written in a variety of +first-order logic. Development of a systematic *programming logic*, +based on extensions of Martin-Löf’s type theory, was undertaken at +Cornell U. by the Nuprl team, headed by R. Constable. The first actual +program extractor, PX, was designed and implemented around 1985 by S. +Hayashi from Kyoto University. It allows the extraction of a LISP +program from a proof in a logical system inspired by the logical +formalisms of S. Feferman. Interest in this methodology is growing in +the theoretical computer science community. We can foresee the day when +actual computer systems used in applications will contain certified +modules, automatically generated from a consistency proof of their +formal specifications. We are however still far from being able to use +this methodology in a smooth interaction with the standard tools from +software engineering, i.e. compilers, linkers, run-time systems taking +advantage of special hardware, debuggers, and the like. We hope that |Coq| +can be of use to researchers interested in experimenting with this new +methodology. + +.. [#years] At the time of writting, i.e. 1995. + +Versions 1 to 5 +--------------- + +.. note:: + This summary was written in 1995 together with the previous + section and formed the initial version of the Credits chapter. + + A more comprehensive description of these early versions is available + in the following subsections, which come from a document written in + September 2015 by Gérard Huet, Thierry Coquand and Christine Paulin. + +A first implementation of CoC was started in 1984 by G. Huet and T. +Coquand. Its implementation language was CAML, a functional programming +language from the ML family designed at INRIA in Rocquencourt. The core +of this system was a proof-checker for CoC seen as a typed +λ-calculus, called the *Constructive Engine*. This engine +was operated through a high-level notation permitting the declaration of +axioms and parameters, the definition of mathematical types and objects, +and the explicit construction of proof objects encoded as +λ-terms. A section mechanism, designed and implemented by +G. Dowek, allowed hierarchical developments of mathematical theories. +This high-level language was called the *Mathematical Vernacular*. +Furthermore, an interactive *Theorem Prover* permitted the incremental +construction of proof trees in a top-down manner, subgoaling recursively +and backtracking from dead-ends. The theorem prover executed tactics +written in CAML, in the LCF fashion. A basic set of tactics was +predefined, which the user could extend by his own specific tactics. +This system (Version 4.10) was released in 1989. Then, the system was +extended to deal with the new calculus with inductive types by C. +Paulin, with corresponding new tactics for proofs by induction. A new +standard set of tactics was streamlined, and the vernacular extended for +tactics execution. A package to compile programs extracted from proofs +to actual computer programs in CAML or some other functional language +was designed and implemented by B. Werner. A new user-interface, relying +on a CAML-X interface by D. de Rauglaudre, was designed and implemented +by A. Felty. It allowed operation of the theorem-prover through the +manipulation of windows, menus, mouse-sensitive buttons, and other +widgets. This system (Version 5.6) was released in 1991. + +Coq was ported to the new implementation Caml-light of X. Leroy and D. +Doligez by D. de Rauglaudre (Version 5.7) in 1992. A new version of |Coq| +was then coordinated by C. Murthy, with new tools designed by C. Parent +to prove properties of ML programs (this methodology is dual to program +extraction) and a new user-interaction loop. This system (Version 5.8) +was released in May 1993. A Centaur interface CTCoq was then developed +by Y. Bertot from the Croap project from INRIA-Sophia-Antipolis. + +In parallel, G. Dowek and H. Herbelin developed a new proof engine, +allowing the general manipulation of existential variables consistently +with dependent types in an experimental version of |Coq| (V5.9). + +The version V5.10 of |Coq| is based on a generic system for manipulating +terms with binding operators due to Chet Murthy. A new proof engine +allows the parallel development of partial proofs for independent +subgoals. The structure of these proof trees is a mixed representation +of derivation trees for the Calculus of Inductive Constructions with +abstract syntax trees for the tactics scripts, allowing the navigation +in a proof at various levels of details. The proof engine allows generic +environment items managed in an object-oriented way. This new +architecture, due to C. Murthy, supports several new facilities which +make the system easier to extend and to scale up: + +- User-programmable tactics are allowed + +- It is possible to separately verify development modules, and to load + their compiled images without verifying them again - a quick + relocation process allows their fast loading + +- A generic parsing scheme allows user-definable notations, with a + symmetric table-driven pretty-printer + +- Syntactic definitions allow convenient abbreviations + +- A limited facility of meta-variables allows the automatic synthesis + of certain type expressions, allowing generic notations for e.g. + equality, pairing, and existential quantification. + +In the Fall of 1994, C. Paulin-Mohring replaced the structure of +inductively defined types and families by a new structure, allowing the +mutually recursive definitions. P. Manoury implemented a translation of +recursive definitions into the primitive recursive style imposed by the +internal recursion operators, in the style of the ProPre system. C. +Muñoz implemented a decision procedure for intuitionistic propositional +logic, based on results of R. Dyckhoff. J.C. Filliâtre implemented a +decision procedure for first-order logic without contraction, based on +results of J. Ketonen and R. Weyhrauch. Finally C. Murthy implemented a +library of inversion tactics, relieving the user from tedious +definitions of “inversion predicates”. + +| Rocquencourt, Feb. 1st 1995 +| Gérard Huet +| + +Version 1 +~~~~~~~~~ + +This software is a prototype type-checker for a higher-order logical +formalism known as the Theory of Constructions, presented in his PhD +thesis by Thierry Coquand, with influences from Girard's system F and +de Bruijn's Automath. The metamathematical analysis of the system is +the PhD work of Thierry Coquand. The software is mostly the work of +Gérard Huet. Most of the mathematical examples verified with the +software are due to Thierry Coquand. + +The programming language of the CONSTR software (as it was called at +the time) was a version of ML adapted from the Edinburgh LCF system +and running on a LISP backend. The main improvements from the original +LCF ML were that ML was compiled rather than interpreted (Gérard Huet +building on the original translator by Lockwood Morris), and that it +was enriched by recursively defined types (work of Guy +Cousineau). This ancestor of CAML was used and improved by Larry +Paulson for his implementation of Cambridge LCF. + +Software developments of this prototype occurred from late 1983 to +early 1985. + +Version 1.10 was frozen on December 22nd 1984. It is the version used +for the examples in Thierry Coquand's thesis, defended on January 31st +1985. There was a unique binding operator, used both for universal +quantification (dependent product) at the level of types and +functional abstraction (λ) at the level of terms/proofs, in the manner +of Automath. Substitution (λ-reduction) was implemented using de +Bruijn's indexes. + +Version 1.11 was frozen on February 19th, 1985. It is the version used +for the examples in the paper: T. Coquand, G. Huet. *Constructions: A +Higher Order Proof System for Mechanizing Mathematics* :cite:`CH85`. + +Christine Paulin joined the team at this point, for her DEA research +internship. In her DEA memoir (August 1985) she presents developments +for the *lambo* function – :math:`\text{lambo}(f)(n)` computes the minimal +:math:`m` such that :math:`f(m)` is greater than :math:`n`, for :math:`f` +an increasing integer function, a challenge for constructive mathematics. +She also encoded the majority voting algorithm of Boyer and Moore. + +Version 2 +~~~~~~~~~ + +The formal system, now renamed as the *Calculus of Constructions*, was +presented with a proof of consistency and comparisons with proof +systems of Per Martin Löf, Girard, and the Automath family of N. de +Bruijn, in the paper: T. Coquand and G. Huet. *The Calculus of +Constructions* :cite:`CH88`. + +An abstraction of the software design, in the form of an abstract +machine for proof checking, and a fuller sequence of mathematical +developments was presented in: T. Coquand, G. Huet. *Concepts +Mathématiques et Informatiques Formalisés dans le Calcul des +Constructions* :cite:`CH87`. + +Version 2.8 was frozen on December 16th, 1985, and served for +developing the examples in the above papers. + +This calculus was then enriched in version 2.9 with a cumulative +hierarchy of universes. Universe levels were initially explicit +natural numbers. Another improvement was the possibility of automatic +synthesis of implicit type arguments, relieving the user of tedious +redundant declarations. + +Christine Paulin wrote an article *Algorithm development in the +Calculus of Constructions* :cite:`P86`. Besides *lambo* and *majority*, +she presents *quicksort* and a text formatting algorithm. + +Version 2.13 of the Calculus of Constructions with universes was +frozen on June 25th, 1986. + +A synthetic presentation of type theory along constructive lines with +ML algorithms was given by Gérard Huet in his May 1986 CMU course +notes *Formal Structures for Computation and Deduction*. Its chapter +*Induction and Recursion in the Theory of Constructions* was presented +as an invited paper at the Joint Conference on Theory and Practice of +Software Development TAPSOFT’87 at Pise in March 1987, and published +as *Induction Principles Formalized in the Calculus of +Constructions* :cite:`H88`. + +Version 3 +~~~~~~~~~ + +This version saw the beginning of proof automation, with a search +algorithm inspired from PROLOG and the applicative logic programming +programs of the course notes *Formal structures for computation and +deduction*. The search algorithm was implemented in ML by Thierry +Coquand. The proof system could thus be used in two modes: proof +verification and proof synthesis, with tactics such as ``AUTO``. + +The implementation language was now called CAML, for Categorical +Abstract Machine Language. It used as backend the LLM3 virtual machine +of Le Lisp by Jérôme Chailloux. The main developers of CAML were +Michel Mauny, Ascander Suarez and Pierre Weis. + +V3.1 was started in the summer of 1986, V3.2 was frozen at the end of +November 1986. V3.4 was developed in the first half of 1987. + +Thierry Coquand held a post-doctoral position in Cambrige University +in 1986-87, where he developed a variant implementation in SML, with +which he wrote some developments on fixpoints in Scott's domains. + +Version 4 +~~~~~~~~~ + +This version saw the beginning of program extraction from proofs, with +two varieties of the type ``Prop`` of propositions, indicating +constructive intent. The proof extraction algorithms were implemented +by Christine Paulin-Mohring. + +V4.1 was frozen on July 24th, 1987. It had a first identified library +of mathematical developments (directory ``exemples``), with libraries +``Logic`` (containing impredicative encodings of intuitionistic logic and +algebraic primitives for booleans, natural numbers and list), ``Peano`` +developing second-order Peano arithmetic, ``Arith`` defining addition, +multiplication, euclidean division and factorial. Typical developments +were the Knaster-Tarski theorem and Newman's lemma from rewriting +theory. + +V4.2 was a joint development of a team consisting of Thierry Coquand, +Gérard Huet and Christine Paulin-Mohring. A file V4.2.log records the +log of changes. It was frozen on September 1987 as the last version +implemented in CAML 2.3, and V4.3 followed on CAML 2.5, a more stable +development system. + +V4.3 saw the first top-level of the system. Instead of evaluating +explicit quotations, the user could develop his mathematics in a +high-level language called the mathematical vernacular (following +Automath terminology). The user could develop files in the vernacular +notation (with ``.v`` extension) which were now separate from the ``ml`` +sources of the implementation. Gilles Dowek joined the team to +develop the vernacular language as his DEA internship research. + +A notion of sticky constant was introduced, in order to keep names of +lemmas when local hypotheses of proofs were discharged. This gave a +notion of global mathematical environment with local sections. + +Another significant practical change was that the system, originally +developped on the VAX central computer of our lab, was transferred on +SUN personal workstations, allowing a level of distributed +development. The extraction algorithm was modified, with three +annotations ``Pos``, ``Null`` and ``Typ`` decorating the sorts ``Prop`` +and ``Type``. + +Version 4.3 was frozen at the end of November 1987, and was +distributed to an early community of users (among those were Hugo +Herbelin and Loic Colson). + +V4.4 saw the first version of (encoded) inductive types. Now natural +numbers could be defined as:: + + [source, coq] + Inductive NAT : Prop = O : NAT | Succ : NAT->NAT. + +These inductive types were encoded impredicatively in the calculus, +using a subsystem *rec* due to Christine Paulin. V4.4 was frozen on +March 6th 1988. + +Version 4.5 was the first one to support inductive types and program +extraction. Its banner was *Calcul des Constructions avec +Réalisations et Synthèse*. The vernacular language was enriched to +accommodate extraction commands. + +The verification engine design was presented as: G. Huet. *The +Constructive Engine*. Version 4.5. Invited Conference, 2nd European +Symposium on Programming, Nancy, March 88. The final paper, +describing the V4.9 implementation, appeared in: A perspective in +Theoretical Computer Science, Commemorative Volume in memory of Gift +Siromoney, Ed. R. Narasimhan, World Scientific Publishing, 1989. + +Version 4.5 was demonstrated in June 1988 at the YoP Institute on +Logical Foundations of Functional Programming organized by Gérard Huet +at Austin, Texas. + +Version 4.6 was started during the summer of 1988. Its main +improvement was the complete rehaul of the proof synthesis engine by +Thierry Coquand, with a tree structure of goals. + +Its source code was communicated to Randy Pollack on September 2nd +1988. It evolved progressively into LEGO, proof system for Luo's +formalism of Extended Calculus of Constructions. + +The discharge tactic was modified by Gérard Huet to allow for +inter-dependencies in discharged lemmas. Christine Paulin improved the +inductive definition scheme in order to accommodate predicates of any +arity. + +Version 4.7 was started on September 6th, 1988. + +This version starts exploiting the CAML notion of module in order to +improve the modularity of the implementation. Now the term verifier is +identified as a proper module Machine, which the structure of its +internal data structures being hidden and thus accessible only through +the legitimate operations. This machine (the constructive engine) was +the trusted core of the implementation. The proof synthesis mechanism +was a separate proof term generator. Once a complete proof term was +synthesized with the help of tactics, it was entirely re-checked by +the engine. Thus there was no need to certify the tactics, and the +system took advantage of this fact by having tactics ignore the +universe levels, universe consistency check being relegated to the +final type-checking pass. This induced a certain puzzlement in early +users who saw, after a successful proof search, their ``QED`` followed +by silence, followed by a failure message due to a universe +inconsistency… + +The set of examples comprise set theory experiments by Hugo Herbelin, +and notably the Schroeder-Bernstein theorem. + +Version 4.8, started on October 8th, 1988, saw a major +re-implementation of the abstract syntax type ``constr``, separating +variables of the formalism and metavariables denoting incomplete terms +managed by the search mechanism. A notion of level (with three values +``TYPE``, ``OBJECT`` and ``PROOF``) is made explicit and a type judgement +clarifies the constructions, whose implementation is now fully +explicit. Structural equality is speeded up by using pointer equality, +yielding spectacular improvements. Thierry Coquand adapts the proof +synthesis to the new representation, and simplifies pattern matching +to first-order predicate calculus matching, with important performance +gain. + +A new representation of the universe hierarchy is then defined by +Gérard Huet. Universe levels are now implemented implicitly, through +a hidden graph of abstract levels constrained with an order relation. +Checking acyclicity of the graph insures well-foundedness of the +ordering, and thus consistency. This was documented in a memo *Adding +Type:Type to the Calculus of Constructions* which was never published. + +The development version is released as a stable 4.8 at the end of +1988. + +Version 4.9 is released on March 1st 1989, with the new "elastic" +universe hierarchy. + +The spring of 1989 saw the first attempt at documenting the system +usage, with a number of papers describing the formalism: + +- *Metamathematical Investigations of a Calculus of Constructions*, by + Thierry Coquand :cite:`C90`, + +- *Inductive definitions in the Calculus of Constructions*, by + Christine Paulin-Mohrin, + +- *Extracting Fω's programs from proofs in the Calculus of + Constructions*, by Christine Paulin-Mohring* :cite:`P89`, + +- *The Constructive Engine*, by Gérard Huet :cite:`H89`, + +as well as a number of user guides: + +- *A short user's guide for the Constructions*, Version 4.10, by Gérard Huet +- *A Vernacular Syllabus*, by Gilles Dowek. +- *The Tactics Theorem Prover, User's guide*, Version 4.10, by Thierry + Coquand. + +Stable V4.10, released on May 1st, 1989, was then a mature system, +distributed with CAML V2.6. + +In the mean time, Thierry Coquand and Christine Paulin-Mohring had +been investigating how to add native inductive types to the Calculus +of Constructions, in the manner of Per Martin-Löf's Intuitionistic +Type Theory. The impredicative encoding had already been presented in: +F. Pfenning and C. Paulin-Mohring. *Inductively defined types in the +Calculus of Constructions* :cite:`PP90`. An extension of the calculus +with primitive inductive types appeared in: T. Coquand and +C. Paulin-Mohring. *Inductively defined types* :cite:`CP90`. + +This led to the Calculus of Inductive Constructions, logical formalism +implemented in Versions 5 upward of the system, and documented in: +C. Paulin-Mohring. *Inductive Definitions in the System Coq - Rules +and Properties* :cite:`P93`. + +The last version of CONSTR is Version 4.11, which was last distributed +in the spring of 1990. It was demonstrated at the first workshop of +the European Basic Research Action Logical Frameworks In Sophia +Antipolis in May 1990. + +Version 5 +~~~~~~~~~ + +At the end of 1989, Version 5.1 was started, and renamed as the system +Coq for the Calculus of Inductive Constructions. It was then ported to +the new stand-alone implementation of ML called Caml-light. + +In 1990 many changes occurred. Thierry Coquand left for Chalmers +University in Göteborg. Christine Paulin-Mohring took a CNRS +researcher position at the LIP laboratory of École Normale Supérieure +de Lyon. Project Formel was terminated, and gave rise to two teams: +Cristal at INRIA-Roquencourt, that continued developments in +functional programming with Caml-light then OCaml, and Coq, continuing +the type theory research, with a joint team headed by Gérard Huet at +INRIA-Rocquencourt and Christine Paulin-Mohring at the LIP laboratory +of CNRS-ENS Lyon. + +Chetan Murthy joined the team in 1991 and became the main software +architect of Version 5. He completely rehauled the implementation for +efficiency. Versions 5.6 and 5.8 were major distributed versions, +with complete documentation and a library of users' developements. The +use of the RCS revision control system, and systematic ChangeLog +files, allow a more precise tracking of the software developments. + +| September 2015 + +| Thierry Coquand, Gérard Huet and Christine Paulin-Mohring. +| + +Versions 6 +---------- + +Version 6.1 +~~~~~~~~~~~ + +The present version 6.1 of |Coq| is based on the V5.10 architecture. It +was ported to the new language Objective Caml by Bruno Barras. The +underlying framework has slightly changed and allows more conversions +between sorts. + +The new version provides powerful tools for easier developments. + +Cristina Cornes designed an extension of the |Coq| syntax to allow +definition of terms using a powerful pattern matching analysis in the +style of ML programs. + +Amokrane Saïbi wrote a mechanism to simulate inheritance between types +families extending a proposal by Peter Aczel. He also developed a +mechanism to automatically compute which arguments of a constant may be +inferred by the system and consequently do not need to be explicitly +written. + +Yann Coscoy designed a command which explains a proof term using natural +language. Pierre Crégut built a new tactic which solves problems in +quantifier-free Presburger Arithmetic. Both functionalities have been +integrated to the |Coq| system by Hugo Herbelin. + +Samuel Boutin designed a tactic for simplification of commutative rings +using a canonical set of rewriting rules and equality modulo +associativity and commutativity. + +Finally the organisation of the |Coq| distribution has been supervised by +Jean-Christophe Filliâtre with the help of Judicaël Courant and Bruno +Barras. + +| Lyon, Nov. 18th 1996 +| Christine Paulin +| + +Version 6.2 +~~~~~~~~~~~ + +In version 6.2 of |Coq|, the parsing is done using camlp4, a preprocessor +and pretty-printer for CAML designed by Daniel de Rauglaudre at INRIA. +Daniel de Rauglaudre made the first adaptation of |Coq| for camlp4, this +work was continued by Bruno Barras who also changed the structure of |Coq| +abstract syntax trees and the primitives to manipulate them. The result +of these changes is a faster parsing procedure with greatly improved +syntax-error messages. The user-interface to introduce grammar or +pretty-printing rules has also changed. + +Eduardo Giménez redesigned the internal tactic libraries, giving uniform +names to Caml functions corresponding to |Coq| tactic names. + +Bruno Barras wrote new, more efficient reduction functions. + +Hugo Herbelin introduced more uniform notations in the |Coq| specification +language: the definitions by fixpoints and pattern matching have a more +readable syntax. Patrick Loiseleur introduced user-friendly notations +for arithmetic expressions. + +New tactics were introduced: Eduardo Giménez improved the mechanism to +introduce macros for tactics, and designed special tactics for +(co)inductive definitions; Patrick Loiseleur designed a tactic to +simplify polynomial expressions in an arbitrary commutative ring which +generalizes the previous tactic implemented by Samuel Boutin. +Jean-Christophe Filliâtre introduced a tactic for refining a goal, using +a proof term with holes as a proof scheme. + +David Delahaye designed the tool to search an object in the library +given its type (up to isomorphism). + +Henri Laulhère produced the |Coq| distribution for the Windows +environment. + +Finally, Hugo Herbelin was the main coordinator of the |Coq| documentation +with principal contributions by Bruno Barras, David Delahaye, +Jean-Christophe Filliâtre, Eduardo Giménez, Hugo Herbelin and Patrick +Loiseleur. + +| Orsay, May 4th 1998 +| Christine Paulin +| + +Version 6.3 +~~~~~~~~~~~ + +The main changes in version V6.3 were the introduction of a few new +tactics and the extension of the guard condition for fixpoint +definitions. + +B. Barras extended the unification algorithm to complete partial terms +and fixed various tricky bugs related to universes. + +D. Delahaye developed the ``AutoRewrite`` tactic. He also designed the +new behavior of ``Intro`` and provided the tacticals ``First`` and +``Solve``. + +J.-C. Filliâtre developed the ``Correctness`` tactic. + +\E. Giménez extended the guard condition in fixpoints. + +H. Herbelin designed the new syntax for definitions and extended the +``Induction`` tactic. + +P. Loiseleur developed the ``Quote`` tactic and the new design of the +``Auto`` tactic, he also introduced the index of errors in the +documentation. + +C. Paulin wrote the ``Focus`` command and introduced the reduction +functions in definitions, this last feature was proposed by J.-F. +Monin from CNET Lannion. + +| Orsay, Dec. 1999 +| Christine Paulin +| + +Versions 7 +---------- + +Summary of changes +~~~~~~~~~~~~~~~~~~ + +The version V7 is a new implementation started in September 1999 by +Jean-Christophe Filliâtre. This is a major revision with respect to the +internal architecture of the system. The |Coq| version 7.0 was distributed +in March 2001, version 7.1 in September 2001, version 7.2 in January +2002, version 7.3 in May 2002 and version 7.4 in February 2003. + +Jean-Christophe Filliâtre designed the architecture of the new system. +He introduced a new representation for environments and wrote a new +kernel for type checking terms. His approach was to use functional +data-structures in order to get more sharing, to prepare the addition of +modules and also to get closer to a certified kernel. + +Hugo Herbelin introduced a new structure of terms with local +definitions. He introduced “qualified” names, wrote a new +pattern matching compilation algorithm and designed a more compact +algorithm for checking the logical consistency of universes. He +contributed to the simplification of |Coq| internal structures and the +optimisation of the system. He added basic tactics for forward reasoning +and coercions in patterns. + +David Delahaye introduced a new language for tactics. General tactics +using pattern matching on goals and context can directly be written from +the |Coq| toplevel. He also provided primitives for the design of +user-defined tactics in Caml. + +Micaela Mayero contributed the library on real numbers. Olivier +Desmettre extended this library with axiomatic trigonometric functions, +square, square roots, finite sums, Chasles property and basic plane +geometry. + +Jean-Christophe Filliâtre and Pierre Letouzey redesigned a new +extraction procedure from |Coq| terms to Caml or Haskell programs. This +new extraction procedure, unlike the one implemented in previous version +of |Coq| is able to handle all terms in the Calculus of Inductive +Constructions, even involving universes and strong elimination. P. +Letouzey adapted user contributions to extract ML programs when it was +sensible. Jean-Christophe Filliâtre wrote ``coqdoc``, a documentation +tool for |Coq| libraries usable from version 7.2. + +Bruno Barras improved the efficiency of the reduction algorithm and the +confidence level in the correctness of |Coq| critical type checking +algorithm. + +Yves Bertot designed the ``SearchPattern`` and ``SearchRewrite`` tools +and the support for the pcoq interface +(http://www-sop.inria.fr/lemme/pcoq/). + +Micaela Mayero and David Delahaye introduced Field, a decision tactic +for commutative fields. + +Christine Paulin changed the elimination rules for empty and singleton +propositional inductive types. + +Loïc Pottier developed Fourier, a tactic solving linear inequalities on +real numbers. + +Pierre Crégut developed a new, reflection-based version of the Omega +decision procedure. + +Claudio Sacerdoti Coen designed an XML output for the |Coq| modules to be +used in the Hypertextual Electronic Library of Mathematics (HELM cf +http://www.cs.unibo.it/helm). + +A library for efficient representation of finite maps using binary trees +contributed by Jean Goubault was integrated in the basic theories. + +Pierre Courtieu developed a command and a tactic to reason on the +inductive structure of recursively defined functions. + +Jacek Chrząszcz designed and implemented the module system of |Coq| whose +foundations are in Judicaël Courant’s PhD thesis. + +The development was coordinated by C. Paulin. + +Many discussions within the Démons team and the LogiCal project +influenced significantly the design of |Coq| especially with J. Courant, +J. Duprat, J. Goubault, A. Miquel, C. Marché, B. Monate and B. Werner. + +Intensive users suggested improvements of the system : Y. Bertot, L. +Pottier, L. Théry, P. Zimmerman from INRIA, C. Alvarado, P. Crégut, +J.-F. Monin from France Telecom R & D. + +| Orsay, May. 2002 +| Hugo Herbelin & Christine Paulin +| + +Details of changes in 7.0 and 7.1 +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Notes: + +- items followed by (**) are important sources of incompatibilities +- items followed by (*) may exceptionally be sources of incompatibilities +- items followed by (+) have been introduced in version 7.0 + + +Main novelties +^^^^^^^^^^^^^^ + +References are to Coq 7.1 reference manual + +- New primitive let-in construct (see sections 1.2.8 and ) +- Long names (see sections 2.6 and 2.7) +- New high-level tactic language (see chapter 10) +- Improved search facilities (see section 5.2) +- New extraction algorithm managing the Type level (see chapter 17) +- New rewriting tactic for arbitrary equalities (see chapter 19) +- New tactic Field to decide equalities on commutative fields (see 7.11) +- New tactic Fourier to solve linear inequalities on reals numbers (see 7.11) +- New tactics for induction/case analysis in "natural" style (see 7.7) +- Deep restructuration of the code (safer, simpler and more efficient) +- Export of theories to XML for publishing and rendering purposes + (see http://www.cs.unibo.it/helm) + + +Details of changes +^^^^^^^^^^^^^^^^^^ + +Language: new "let-in" construction +*********************************** + +- New construction for local definitions (let-in) with syntax [x:=u]t (*)(+) + +- Local definitions allowed in Record (a.k.a. record à la Randy Pollack) + + +Language: long names +******************** + +- Each construction has a unique absolute names built from a base + name, the name of the module in which they are defined (Top if in + coqtop), and possibly an arbitrary long sequence of directory (e.g. + "Coq.Lists.PolyList.flat_map" where "Coq" means that "flat_map" is part + of Coq standard library, "Lists" means it is defined in the Lists + library and "PolyList" means it is in the file Polylist) (+) + +- Constructions can be referred by their base name, or, in case of + conflict, by a "qualified" name, where the base name is prefixed + by the module name (and possibly by a directory name, and so + on). A fully qualified name is an absolute name which always refer + to the construction it denotes (to preserve the visibility of + all constructions, no conflict is allowed for an absolute name) (+) + +- Long names are available for modules with the possibility of using + the directory name as a component of the module full name (with + option -R to coqtop and coqc, or command Add LoadPath) (+) + +- Improved conflict resolution strategy (the Unix PATH model), + allowing more constructions to be referred just by their base name + + +Language: miscellaneous +*********************** + +- The names of variables for Record projections _and_ for induction principles + (e.g. sum_ind) is now based on the first letter of their type (main + source of incompatibility) (**)(+) + +- Most typing errors have now a precise location in the source (+) + +- Slightly different mechanism to solve "?" (*)(+) + +- More arguments may be considered implicit at section closing (*)(+) + +- Bug with identifiers ended by a number greater than 2^30 fixed (+) + +- New visibility discipline for Remark, Fact and Local: Remark's and + Fact's now survive at the end of section, but are only accessible using a + qualified names as soon as their strength expires; Local's disappear and + are moved into local definitions for each construction persistent at + section closing + + +Language: Cases +*************** + +- Cases no longer considers aliases inferable from dependencies in types (*)(+) + +- A redundant clause in Cases is now an error (*) + + +Reduction +********* + +- New reduction flags "Zeta" and "Evar" in Eval Compute, for inlining of + local definitions and instantiation of existential variables + +- Delta reduction flag does not perform Zeta and Evar reduction any more (*) + +- Constants declared as opaque (using Qed) can no longer become + transparent (a constant intended to be alternatively opaque and + transparent must be declared as transparent (using Defined)); a risk + exists (until next Coq version) that Simpl and Hnf reduces opaque + constants (*) + + +New tactics +*********** + +- New set of tactics to deal with types equipped with specific + equalities (a.k.a. Setoids, e.g. nat equipped with eq_nat) [by C. Renard] + +- New tactic Assert, similar to Cut but expected to be more user-friendly + +- New tactic NewDestruct and NewInduction intended to replace Elim + and Induction, Case and Destruct in a more user-friendly way (see + restrictions in the reference manual) + +- New tactic ROmega: an experimental alternative (based on reflexion) to Omega + [by P. Crégut] + +- New tactic language Ltac (see reference manual) (+) + +- New versions of Tauto and Intuition, fully rewritten in the new Ltac + language; they run faster and produce more compact proofs; Tauto is + fully compatible but, in exchange of a better uniformity, Intuition + is slightly weaker (then use Tauto instead) (**)(+) + +- New tactic Field to decide equalities on commutative fields (as a + special case, it works on real numbers) (+) + +- New tactic Fourier to solve linear inequalities on reals numbers + [by L. Pottier] (+) + +- New tactics dedicated to real numbers: DiscrR, SplitRmult, SplitAbsolu (+) + + +Changes in existing tactics +*************************** + +- Reduction tactics in local definitions apply only to the body + +- New syntax of the form "Compute in Type of H." to require a reduction on + the types of local definitions + +- Inversion, Injection, Discriminate, ... apply also on the + quantified premises of a goal (using the "Intros until" syntax) + +- Decompose has been fixed but hypotheses may get different names (*)(+) + +- Tauto now manages uniformly hypotheses and conclusions of the form + ``t=t`` which all are considered equivalent to ``True``. Especially, + Tauto now solves goals of the form ``H : ~ t = t |- A``. + +- The "Let" tactic has been renamed "LetTac" and is now based on the + primitive "let-in" (+) + +- Elim can no longer be used with an elimination schema different from + the one defined at definition time of the inductive type. To overload + an elimination schema, use "Elim <hyp> using <name of the new schema>" + (*)(+) + +- Simpl no longer unfolds the recursive calls of a mutually defined + fixpoint (*)(+) + +- Intro now fails if the hypothesis name already exists (*)(+) + +- "Require Prolog" is no longer needed (i.e. it is available by default) (*)(+) + +- Unfold now fails on a non unfoldable identifier (*)(+) + +- Unfold also applies on definitions of the local context + +- AutoRewrite now deals only with the main goal and it is the purpose of + Hint Rewrite to deal with generated subgoals (+) + +- Redundant or incompatible instantiations in Apply ... with ... are now + correctly managed (+) + + +Efficiency +********** + +- Excessive memory uses specific to V7.0 fixed + +- Sizes of .vo files vary a lot compared to V6.3 (from -30% to +300% + depending on the developments) + +- An improved reduction strategy for lazy evaluation + +- A more economical mechanism to ensure logical consistency at the Type level; + warning: this is experimental and may produce "universes" anomalies + (please report) + + +Concrete syntax of constructions +******************************** + +- Only identifiers starting with "_" or a letter, and followed by letters, + digits, "_" or "'" are allowed (e.g. "$" and "@" are no longer allowed) (*) + +- A multiple binder like (a:A)(a,b:(P a))(Q a) is no longer parsed as + (a:A)(a0:(P a))(b:(P a))(Q a0) but as (a:A)(a0:(P a))(b:(P a0))(Q a0) (*)(+) + +- A dedicated syntax has been introduced for Reals (e.g ``3+1/x``) (+) + +- Pretty-printing of Infix notations fixed. (+) + + +Parsing and grammar extension +***************************** + +- More constraints when writing ast + + - "{...}" and the macros $LIST, $VAR, etc. now expect a metavariable + (an identifier starting with $) (*) + - identifiers should starts with a letter or "_" and be followed + by letters, digits, "_" or "'" (other characters are still + supported but it is not advised to use them) (*)(+) + +- Entry "command" in "Grammar" and quotations (<<...>> stuff) is + renamed "constr" as in "Syntax" (+) + +- New syntax "[" sentence_1 ... sentence_n"]." to group sentences (useful + for Time and to write grammar rules abbreviating several commands) (+) + +- The default parser for actions in the grammar rules (and for + patterns in the pretty-printing rules) is now the one associated to + the grammar (i.e. vernac, tactic or constr); no need then for + quotations as in <:vernac:<...>>; to return an "ast", the grammar + must be explicitly typed with tag ": ast" or ": ast list", or if a + syntax rule, by using <<...>> in the patterns (expression inside + these angle brackets are parsed as "ast"); for grammars other than + vernac, tactic or constr, you may explicitly type the action with + tags ": constr", ": tactic", or ":vernac" (**)(+) + +- Interpretation of names in Grammar rule is now based on long names, + which allows to avoid problems (or sometimes tricks;) related to + overloaded names (+) + + +New commands +************ + +- New commands "Print XML All", "Show XML Proof", ... to show or + export theories to XML to be used with Helm's publishing and rendering + tools (see http://www.cs.unibo.it/helm) (by Claudio Sacerdoti Coen) (+) + +- New commands to manually set implicit arguments (+) + + - "Implicits ident." to activate the implicit arguments mode just for ident + - "Implicits ident [num1 num2 ...]." to explicitly give which + arguments have to be considered as implicit + +- New SearchPattern/SearchRewrite (by Yves Bertot) (+) + +- New commands "Debug on"/"Debug off" to activate/deactivate the tactic + language debugger (+) + +- New commands to map physical paths to logical paths (+) + - Add LoadPath physical_dir as logical_dir + - Add Rec LoadPath physical_dir as logical_dir + + +Changes in existing commands +**************************** + +- Generalization of the usage of qualified identifiers in tactics + and commands about globals, e.g. Decompose, Eval Delta; + Hints Unfold, Transparent, Require + +- Require synchronous with Reset; Require's scope stops at Section ending (*) + +- For a module indirectly loaded by a "Require" but not exported, + the command "Import module" turns the constructions defined in the + module accessible by their short name, and activates the Grammar, + Syntax, Hint, ... declared in the module (+) + +- The scope of the "Search" command can be restricted to some modules (+) + +- Final dot in command (full stop/period) must be followed by a blank + (newline, tabulation or whitespace) (+) + +- Slight restriction of the syntax for Cbv Delta: if present, option [-myconst] + must immediately follow the Delta keyword (*)(+) + +- SearchIsos currently not supported + +- Add ML Path is now implied by Add LoadPath (+) + +- New names for the following commands (+) + + AddPath -> Add LoadPath + Print LoadPath -> Print LoadPath + DelPath -> Remove LoadPath + AddRecPath -> Add Rec LoadPath + Print Path -> Print Coercion Paths + + Implicit Arguments On -> Set Implicit Arguments + Implicit Arguments Off -> Unset Implicit Arguments + + Begin Silent -> Set Silent + End Silent -> Unset Silent. + + +Tools +***** + +- coqtop (+) + + - Two executables: coqtop.byte and coqtop.opt (if supported by the platform) + - coqtop is a link to the more efficient executable (coqtop.opt if present) + - option -full is obsolete (+) + +- do_Makefile renamed into coq_makefile (+) + +- New option -R to coqtop and coqc to map a physical directory to a logical + one (+) + +- coqc no longer needs to create a temporary file + +- No more warning if no initialization file .coqrc exists + + +Extraction +********** + +- New algorithm for extraction able to deal with "Type" (+) + (by J.-C. Filliâtre and P. Letouzey) + + +Standard library +**************** + +- New library on maps on integers (IntMap, contributed by Jean Goubault) + +- New lemmas about integer numbers [ZArith] + +- New lemmas and a "natural" syntax for reals [Reals] (+) + +- Exc/Error/Value renamed into Option/Some/None (*) + + +New user contributions +********************** + +- Constructive complex analysis and the Fundamental Theorem of Algebra [FTA] + (Herman Geuvers, Freek Wiedijk, Jan Zwanenburg, Randy Pollack, + Henk Barendregt, Nijmegen) + +- A new axiomatization of ZFC set theory [Functions_in_ZFC] + (C. Simpson, Sophia-Antipolis) + +- Basic notions of graph theory [GRAPHS-BASICS] (Jean Duprat, Lyon) + +- A library for floating-point numbers [Float] (Laurent Théry, Sylvie Boldo, + Sophia-Antipolis) + +- Formalisation of CTL and TCTL temporal logic [CtlTctl] (Carlos + Daniel Luna,Montevideo) + +- Specification and verification of the Railroad Crossing Problem + in CTL and TCTL [RailroadCrossing] (Carlos Daniel Luna,Montevideo) + +- P-automaton and the ABR algorithm [PAutomata] + (Christine Paulin, Emmanuel Freund, Orsay) + +- Semantics of a subset of the C language [MiniC] + (Eduardo Giménez, Emmanuel Ledinot, Suresnes) + +- Correctness proofs of the following imperative algorithms: + Bresenham line drawing algorithm [Bresenham], Marché's minimal edition + distance algorithm [Diff] (Jean-Christophe Filliâtre, Orsay) + +- Correctness proofs of Buchberger's algorithm [Buchberger] and RSA + cryptographic algorithm [Rsa] (Laurent Théry, Sophia-Antipolis) + +- Correctness proof of Stalmarck tautology checker algorithm + [Stalmarck] (Laurent Théry, Pierre Letouzey, Sophia-Antipolis) + + +Details of changes in 7.2 +~~~~~~~~~~~~~~~~~~~~~~~~~ + +Language + +- Automatic insertion of patterns for local definitions in the type of + the constructors of an inductive types (for compatibility with V6.3 + let-in style) +- Coercions allowed in Cases patterns +- New declaration "Canonical Structure id = t : I" to help resolution of + equations of the form (proj ?)=a; if proj(e)=a then a is canonically + equipped with the remaining fields in e, i.e. ? is instantiated by e + +Tactics + +- New tactic "ClearBody H" to clear the body of definitions in local context +- New tactic "Assert H := c" for forward reasoning +- Slight improvement in naming strategy for NewInduction/NewDestruct +- Intuition/Tauto do not perform useless unfolding and work up to conversion + +Extraction (details in plugins/extraction/CHANGES or documentation) + +- Syntax changes: there are no more options inside the extraction commands. + New commands for customization and options have been introduced instead. +- More optimizations on extracted code. +- Extraction tests are now embedded in 14 user contributions. + +Standard library + +- In [Relations], Rstar.v and Newman.v now axiom-free. +- In [Sets], Integers.v now based on nat +- In [Arith], more lemmas in Min.v, new file Max.v, tail-recursive + plus and mult added to Plus.v and Mult.v respectively +- New directory [Sorting] with a proof of heapsort (dragged from 6.3.1 lib) +- In [Reals], more lemmas in Rbase.v, new lemmas on square, square root and + trigonometric functions (R_sqr.v - Rtrigo.v); a complementary approach + and new theorems about continuity and derivability in Ranalysis.v; some + properties in plane geometry such as translation, rotation or similarity + in Rgeom.v; finite sums and Chasles property in Rsigma.v + +Bugs + +- Confusion between implicit args of locals and globals of same base name fixed +- Various incompatibilities wrt inference of "?" in V6.3.1 fixed +- Implicits in infix section variables bug fixed +- Known coercions bugs fixed + +- Apply "universe anomaly" bug fixed +- NatRing now working +- "Discriminate 1", "Injection 1", "Simplify_eq 1" now working +- NewInduction bugs with let-in and recursively dependent hypotheses fixed +- Syntax [x:=t:T]u now allowed as mentioned in documentation + +- Bug with recursive inductive types involving let-in fixed +- Known pattern-matching bugs fixed +- Known Cases elimination predicate bugs fixed +- Improved errors messages for pattern-matching and projections +- Better error messages for ill-typed Cases expressions + +Incompatibilities + +- New naming strategy for NewInduction/NewDestruct may affect 7.1 compatibility +- Extra parentheses may exceptionally be needed in tactic definitions. +- Coq extensions written in Ocaml need to be updated (see dev/changements.txt + for a description of the main changes in the interface files of V7.2) +- New behaviour of Intuition/Tauto may exceptionally lead to incompatibilities + + +Details of changes in 7.3 +~~~~~~~~~~~~~~~~~~~~~~~~~ + +Language + +- Slightly improved compilation of pattern-matching (slight source of + incompatibilities) +- Record's now accept anonymous fields "_" which does not build projections +- Changes in the allowed elimination sorts for certain class of inductive + definitions : an inductive definition without constructors + of Sort Prop can be eliminated on sorts Set and Type A "singleton" + inductive definition (one constructor with arguments in the sort Prop + like conjunction of two propositions or equality) can be eliminated + directly on sort Type (In V7.2, only the sorts Prop and Set were allowed) + +Tactics + +- New tactic "Rename x into y" for renaming hypotheses +- New tactics "Pose x:=u" and "Pose u" to add definitions to local context +- Pattern now working on partially applied subterms +- Ring no longer applies irreversible congruence laws of mult but + better applies congruence laws of plus (slight source of incompatibilities). +- Field now accepts terms to be simplified as arguments (as for Ring). This + extension has been also implemented using the toplevel tactic language. +- Intuition does no longer unfold constants except "<->" and "~". It + can be parameterized by a tactic. It also can introduce dependent + product if needed (source of incompatibilities) +- "Match Context" now matching more recent hypotheses first and failing only + on user errors and Fail tactic (possible source of incompatibilities) +- Tactic Definition's without arguments now allowed in Coq states +- Better simplification and discrimination made by Inversion (source + of incompatibilities) + +Bugs + +- "Intros H" now working like "Intro H" trying first to reduce if not a product +- Forward dependencies in Cases now taken into account +- Known bugs related to Inversion and let-in's fixed +- Bug unexpected Delta with let-in now fixed + +Extraction (details in plugins/extraction/CHANGES or documentation) + +- Signatures of extracted terms are now mostly expunged from dummy arguments. +- Haskell extraction is now operational (tested & debugged). + +Standard library + +- Some additions in [ZArith]: three files (Zcomplements.v, Zpower.v + and Zlogarithms.v) moved from plugins/omega in order to be more + visible, one Zsgn function, more induction principles (Wf_Z.v and + tail of Zcomplements.v), one more general Euclid theorem +- Peano_dec.v and Compare_dec.v now part of Arith.v + +Tools + +- new option -dump-glob to coqtop to dump globalizations (to be used by the + new documentation tool coqdoc; see http://www.lri.fr/~filliatr/coqdoc) + +User Contributions + +- CongruenceClosure (congruence closure decision procedure) + [Pierre Corbineau, ENS Cachan] +- MapleMode (an interface to embed Maple simplification procedures over + rational fractions in Coq) + [David Delahaye, Micaela Mayero, Chalmers University] +- Presburger: A formalization of Presburger's algorithm + [Laurent Thery, INRIA Sophia Antipolis] +- Chinese has been rewritten using Z from ZArith as datatype + ZChinese is the new version, Chinese the obsolete one + [Pierre Letouzey, LRI Orsay] + +Incompatibilities + +- Ring: exceptional incompatibilities (1 above 650 in submitted user + contribs, leading to a simplification) +- Intuition: does not unfold any definition except "<->" and "~" +- Cases: removal of some extra Cases in configurations of the form + "Cases ... of C _ => ... | _ D => ..." (effects on 2 definitions of + submitted user contributions necessitating the removal of now superfluous + proof steps in 3 different proofs) +- Match Context, in case of incompatibilities because of a now non + trapped error (e.g. Not_found or Failure), use instead tactic Fail + to force Match Context trying the next clause +- Inversion: better simplification and discrimination may occasionally + lead to less subgoals and/or hypotheses and different naming of hypotheses +- Unification done by Apply/Elim has been changed and may exceptionally lead + to incompatible instantiations +- Peano_dec.v and Compare_dec.v parts of Arith.v make Auto more + powerful if these files were not already required (1 occurrence of + this in submitted user contribs) + + +Changes in 7.3.1 +^^^^^^^^^^^^^^^^ + +Bug fixes + + - Corrupted Field tactic and Match Context tactic construction fixed + - Checking of names already existing in Assert added (#1386) + - Invalid argument bug in Exact tactic solved (#1387) + - Colliding bound names bug fixed (#1412) + - Wrong non-recursivity test for Record fixed (#1394) + - Out of memory/seg fault bug related to parametric inductive fixed (#1404) + - Setoid_replace/Setoid_rewrite bug wrt "==" fixed + +Misc + + - Ocaml version >= 3.06 is needed to compile Coq from sources + - Simplification of fresh names creation strategy for Assert, Pose and + LetTac (#1402) + + +Details of changes in 7.4 +~~~~~~~~~~~~~~~~~~~~~~~~~ + +Symbolic notations + +- Introduction of a notion of scope gathering notations in a consistent set; + a notation sets has been developed for nat, Z and R (undocumented) +- New command "Notation" for declaring notations simultaneously for + parsing and printing (see chap 10 of the reference manual) +- Declarations with only implicit arguments now handled (e.g. the + argument of nil can be set implicit; use !nil to refer to nil + without arguments) +- "Print Scope sc" and "Locate ntn" allows to know to what expression a + notation is bound +- New defensive strategy for printing or not implicit arguments to ensure + re-type-checkability of the printed term +- In Grammar command, the only predefined non-terminal entries are ident, + global, constr and pattern (e.g. nvar, numarg disappears); the only + allowed grammar types are constr and pattern; ast and ast list are no + longer supported; some incompatibilities in Grammar: when a syntax is a + initial segment of an other one, Grammar does not work, use Notation + +Library + +- Lemmas in Set from Compare_dec.v (le_lt_dec, ...) and Wf_nat.v + (lt_wf_rec, ...) are now transparent. This may be source of + incompatibilities. +- Syntactic Definitions Fst, Snd, Ex, All, Ex2, AllT, ExT, ExT2, + ProjS1, ProjS2, Error, Value and Except are turned to + notations. They now must be applied (incompatibilities only in + unrealistic cases). +- More efficient versions of Zmult and times (30% faster) +- Reals: the library is now divided in 6 parts (Rbase, Rfunctions, + SeqSeries, Rtrigo, Ranalysis, Integration). New tactics: Sup and + RCompute. See Reals.v for details. + +Modules + +- Beta version, see doc chap 2.5 for commands and chap 5 for theory + +Language + +- Inductive definitions now accept ">" in constructor types to declare + the corresponding constructor as a coercion. +- Idem for assumptions declarations and constants when the type is mentionned. +- The "Coercion" and "Canonical Structure" keywords now accept the + same syntax as "Definition", i.e. "hyps :=c (:t)?" or "hyps :t". +- Theorem-like declaration now accepts the syntax "Theorem thm [x:t;...] : u". +- Remark's and Fact's now definitively behave as Theorem and Lemma: when + sections are closed, the full name of a Remark or a Fact has no longer a + section part (source of incompatibilities) +- Opaque Local's (i.e. built by tactics and ended by Qed), do not + survive section closing any longer; as a side-effect, Opaque Local's + now appear in the local context of proofs; their body is hidden + though (source of incompatibilities); use one of Remark/Fact/Lemma/Theorem + instead to simulate the old behaviour of Local (the section part of + the name is not kept though) + +ML tactic and vernacular commands + +- "Grammar tactic" and "Grammar vernac" of type "ast" are no longer + supported (only "Grammar tactic simple_tactic" of type "tactic" + remains available). +- Concrete syntax for ML written vernacular commands and tactics is + now declared at ML level using camlp4 macros TACTIC EXTEND et VERNAC + COMMAND EXTEND. +- "Check n c" now "n:Check c", "Eval n ..." now "n:Eval ..." +- ``Proof with T`` (no documentation) +- SearchAbout id - prints all theorems which contain id in their type + +Tactic definitions + +- Static globalisation of identifiers and global references (source of + incompatibilities, especially, Recursive keyword is required for + mutually recursive definitions). +- New evaluation semantics: no more partial evaluation at definition time; + evaluation of all Tactic/Meta Definition, even producing terms, expect + a proof context to be evaluated (especially "()" is no longer needed). +- Debugger now shows the nesting level and the reasons of failure + +Tactics + +- Equality tactics (Rewrite, Reflexivity, Symmetry, Transitivity) now + understand JM equality +- Simpl and Change now apply to subterms also +- "Simpl f" reduces subterms whose head constant is f +- Double Induction now referring to hypotheses like "Intros until" +- "Inversion" now applies also on quantified hypotheses (naming as + for Intros until) +- NewDestruct now accepts terms with missing hypotheses +- NewDestruct and NewInduction now accept user-provided elimination scheme +- NewDestruct and NewInduction now accept user-provided introduction names +- Omega could solve goals such as ``~x<y |- x>=y`` but failed when the + hypothesis was unfolded to ``x < y -> False``. This is fixed. In addition, + it can also recognize 'False' in the hypothesis and use it to solve the + goal. +- Coercions now handled in "with" bindings +- "Subst x" replaces all ocurrences of x by t in the goal and hypotheses + when an hypothesis x=t or x:=t or t=x exists +- Fresh names for Assert and Pose now based on collision-avoiding + Intro naming strategy (exceptional source of incompatibilities) +- LinearIntuition (no documentation) +- Unfold expects a correct evaluable argument +- Clear expects existing hypotheses + +Extraction (See details in plugins/extraction/CHANGES and README): + +- An experimental Scheme extraction is provided. +- Concerning Ocaml, extracted code is now ensured to always type-check, + thanks to automatic inserting of Obj.magic. +- Experimental extraction of Coq new modules to Ocaml modules. + +Proof rendering in natural language + +- Export of theories to XML for publishing and rendering purposes now + includes proof-trees (see http://www.cs.unibo.it/helm) + +Miscellaneous + +- Printing Coercion now used through the standard keywords Set/Add, Test, Print +- "Print Term id" is an alias for "Print id" +- New switch "Unset/Set Printing Symbols" to control printing of + symbolic notations +- Two new variants of implicit arguments are available + + + ``Unset``/``Set Contextual Implicits`` tells to consider implicit also the + arguments inferable from the context (e.g. for nil or refl_eq) + + ``Unset``/``Set Strict Implicits`` tells to consider implicit only the + arguments that are inferable in any case (i.e. arguments that occurs + as argument of rigid constants in the type of the remaining arguments; + e.g. the witness of an existential is not strict since it can vanish when + applied to a predicate which does not use its argument) + +Incompatibilities + +- "Grammar tactic ... : ast" and "Grammar vernac ... : ast" are no + longer supported, use TACTIC EXTEND and VERNAC COMMAND EXTEND on the + ML-side instead +- Transparency of le_lt_dec and co (leads to some simplification in + proofs; in some cases, incompatibilites is solved by declaring locally + opaque the relevant constant) +- Opaque Local do not now survive section closing (rename them into + Remark/Lemma/... to get them still surviving the sections; this + renaming allows also to solve incompatibilites related to now + forbidden calls to the tactic Clear) +- Remark and Fact have no longer (very) long names (use Local instead in case + of name conflict) + +Bugs + +- Improved localisation of errors in Syntactic Definitions +- Induction principle creation failure in presence of let-in fixed (#1459) +- Inversion bugs fixed (#1427 and #1437) +- Omega bug related to Set fixed (#1384) +- Type-checking inefficiency of nested destructuring let-in fixed (#1435) +- Improved handling of let-in during holes resolution phase (#1460) + +Efficiency + +- Implementation of a memory sharing strategy reducing memory + requirements by an average ratio of 3. diff --git a/doc/sphinx/index.html.rst b/doc/sphinx/index.html.rst index 5a349fcf75..a91c6a9c5f 100644 --- a/doc/sphinx/index.html.rst +++ b/doc/sphinx/index.html.rst @@ -23,7 +23,8 @@ Contents :caption: Preamble self - credits + history + changes .. toctree:: :caption: The language diff --git a/doc/sphinx/index.latex.rst b/doc/sphinx/index.latex.rst index ff3971aee4..708820fff7 100644 --- a/doc/sphinx/index.latex.rst +++ b/doc/sphinx/index.latex.rst @@ -15,7 +15,9 @@ Introduction Company-Coq :cite:`Pit16` (see https://github.com/cpitclaudel/company-coq). -.. include:: credits.rst +.. include:: history.rst + +.. include:: changes.rst ------------ The language diff --git a/doc/sphinx/language/gallina-specification-language.rst b/doc/sphinx/language/gallina-specification-language.rst index 8a5e9d87f8..5a1af9f9fa 100644 --- a/doc/sphinx/language/gallina-specification-language.rst +++ b/doc/sphinx/language/gallina-specification-language.rst @@ -74,14 +74,20 @@ Identifiers and access identifiers `.` (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. +Numerals + Numerals are sequences of digits with a potential fractional part + and exponent. Integers are numerals without fractional nor exponent + part and optionally preceded by a minus sign. Underscores ``_`` can + be used as comments in numerals. .. productionlist:: coq digit : 0..9 num : `digit`…`digit` integer : [-]`num` + dot : . + exp : e | E + sign : + | - + numeral : `num`[`dot` `num`][`exp`[`sign`]`num`] Strings Strings are delimited by ``"`` (double quote), and enclose a sequence of diff --git a/doc/sphinx/practical-tools/utilities.rst b/doc/sphinx/practical-tools/utilities.rst index 7c78e1a50f..8346b72cb9 100644 --- a/doc/sphinx/practical-tools/utilities.rst +++ b/doc/sphinx/practical-tools/utilities.rst @@ -34,9 +34,16 @@ For example, to statically link |Ltac|, you can just do: and similarly for other plugins. +Building a |Coq| project +------------------------ + +As of today it is possible to build Coq projects using two tools: + +- coq_makefile, which is distributed by Coq and is based on generating a makefile, +- Dune, the standard OCaml build tool, which, since version 1.9, supports building Coq libraries. 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 @@ -119,7 +126,7 @@ 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. @@ -205,7 +212,7 @@ The following makefile rules can be extended. 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. @@ -385,7 +392,7 @@ line timing data: Reusing/extending the generated Makefile -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +++++++++++++++++++++++++++++++++++++++++ Including the generated makefile with an include directive is discouraged. The contents of this file, including variable names and @@ -429,7 +436,7 @@ have a generic target for invoking unknown targets. 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``. @@ -452,11 +459,90 @@ To build, say, two targets foo.vo and bar.vo in parallel one can use -Module dependencies --------------------- +Building a |Coq| project with Dune +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +.. note:: + + The canonical documentation for the Coq Dune extension is + maintained upstream; please refer to the `Dune manual + <https://dune.readthedocs.io/>`_ for up-to-date information. + +Building a Coq project with Dune requires setting up a Dune project +for your files. This involves adding a ``dune-project`` and +``pkg.opam`` file to the root (``pkg.opam`` can be empty), and then +providing ``dune`` files in the directories your ``.v`` files are +placed. For the experimental version "0.1" of the Coq Dune language, +|Coq| library stanzas look like: + +.. code:: scheme -In order to compute module dependencies (so to use ``make``), |Coq| comes -with an appropriate tool, ``coqdep``. + (coqlib + (name <module_prefix>) + (public_name <package.lib_name>) + (synopsis <text>) + (modules <ordered_set_lang>) + (libraries <ocaml_libraries>) + (flags <coq_flags>)) + +This stanza will build all `.v` files in the given directory, wrapping +the library under ``<module_prefix>``. If you declare a +``<package.lib_name>`` a ``.install`` file for the library will be +generated; the optional ``<modules>`` field allows you to filter +the list of modules, and ``<libraries>`` allows to depend on ML +plugins. For the moment, Dune relies on Coq's standard mechanisms +(such as ``COQPATH``) to locate installed Coq libraries. + +By default Dune will skip ``.v`` files present in subdirectories. In +order to enable the usual recursive organization of Coq projects add + +.. code:: scheme + + (include_subdirs qualified) + +to you ``dune`` file. + +Once your project is set up, `dune build` will generate the +`pkg.install` files and all the files necessary for the installation +of your project. + +.. example:: + + A typical stanza for a Coq plugin is split into two parts. An OCaml build directive, which is standard Dune: + + .. code:: scheme + + (library + (name equations_plugin) + (public_name equations.plugin) + (flags :standard -warn-error -3-9-27-32-33-50) + (libraries coq.plugins.cc coq.plugins.extraction)) + + (rule + (targets g_equations.ml) + (deps (:pp-file g_equations.mlg)) + (action (run coqpp %{pp-file}))) + + And a Coq-specific part that depends on it via the ``libraries`` field: + + .. code:: scheme + + (coqlib + (name Equations) ; -R flag + (public_name equations.Equations) + (synopsis "Equations Plugin") + (libraries coq.plugins.extraction equations.plugin) + (modules :standard \ IdDec NoCycle)) ; exclude some modules that don't build + + (include_subdirs qualified) + +.. _coqdep: + +Computing Module dependencies +----------------------------- + +In order to compute module dependencies (to be used by ``make`` or +``dune``), |Coq| provides the ``coqdep`` tool. ``coqdep`` computes inter-module dependencies for |Coq| and |OCaml| programs, and prints the dependencies on the standard output in a @@ -474,10 +560,8 @@ done approximately and you are advised to use ``ocamldep`` instead for the 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. - +Both Dune and ``coq_makefile`` use ``coqdep`` to compute the +dependencies among the files part of a Coq project. .. _coqdoc: diff --git a/doc/sphinx/proof-engine/tactics.rst b/doc/sphinx/proof-engine/tactics.rst index 7b395900e9..afb0239be4 100644 --- a/doc/sphinx/proof-engine/tactics.rst +++ b/doc/sphinx/proof-engine/tactics.rst @@ -3912,6 +3912,8 @@ At Coq startup, only the core database is nonempty and can be used. environment, including those used for ``setoid_rewrite``, from the Classes directory. +:fset: internal database for the implementation of the ``FSets`` library. + You are advised not to put your own hints in the core database, but use one or several databases specific to your development. diff --git a/doc/sphinx/proof-engine/vernacular-commands.rst b/doc/sphinx/proof-engine/vernacular-commands.rst index 3e8dd25ee0..e207a072cc 100644 --- a/doc/sphinx/proof-engine/vernacular-commands.rst +++ b/doc/sphinx/proof-engine/vernacular-commands.rst @@ -510,6 +510,20 @@ Requests to the environment .. seealso:: Section :ref:`locating-notations` +.. _printing-flags: + +Printing flags +------------------------------- + +.. flag:: Fast Name Printing + + When turned on, |Coq| uses an asymptotically faster algorithm for the + generation of unambiguous names of bound variables while printing terms. + While faster, it is also less clever and results in a typically less elegant + display, e.g. it will generate more names rather than reusing certain names + across subterms. This flag is not enabled by default, because as Ltac + observes bound names, turning it on can break existing proof scripts. + .. _loading-files: diff --git a/doc/sphinx/user-extensions/syntax-extensions.rst b/doc/sphinx/user-extensions/syntax-extensions.rst index e5eb7eb4f5..63df3d37bf 100644 --- a/doc/sphinx/user-extensions/syntax-extensions.rst +++ b/doc/sphinx/user-extensions/syntax-extensions.rst @@ -943,8 +943,8 @@ instance the infix symbol ``+``, can be used to denote distinct definitions of the additive operator. Depending on which interpretation scopes are currently open, the interpretation is different. Interpretation scopes can include an interpretation for numerals and -strings. However, this is only made possible at the Objective Caml -level. +strings, either at the OCaml level or using :cmd:`Numeral Notation` +or :cmd:`String Notation`. .. cmd:: Declare Scope @scope @@ -1214,7 +1214,7 @@ Scopes` or :cmd:`Print Scope`. ``nat_scope`` This scope includes the standard arithmetical operators and relations on type - nat. Positive numerals in this scope are mapped to their canonical + nat. Positive integer numerals in this scope are mapped to their canonical representent built from :g:`O` and :g:`S`. The scope is delimited by the key ``nat``, and bound to the type :g:`nat` (see above). @@ -1238,20 +1238,19 @@ Scopes` or :cmd:`Print Scope`. This scope includes the standard arithmetical operators and relations on type :g:`Q` (rational numbers defined as fractions of an integer and a strictly positive integer modulo the equality of the numerator- - denominator cross-product). As for numerals, only 0 and 1 have an - interpretation in scope ``Q_scope`` (their interpretations are 0/1 and 1/1 - respectively). + denominator cross-product) and comes with an interpretation for numerals + as closed terms of type :g:`Q`. ``Qc_scope`` This scope includes the standard arithmetical operators and relations on the type :g:`Qc` of rational numbers defined as the type of irreducible fractions of an integer and a strictly positive integer. -``real_scope`` +``R_scope`` This scope includes the standard arithmetical operators and relations on type :g:`R` (axiomatic real numbers). It is delimited by the key ``R`` and comes with an interpretation for numerals using the :g:`IZR` morphism from binary - integer numbers to :g:`R`. + integer numbers to :g:`R` and :g:`Z.pow_pos` for potential exponent parts. ``bool_scope`` This scope includes notations for the boolean operators. It is delimited by the @@ -1458,6 +1457,8 @@ Numeral notations * :n:`Decimal.uint -> option @ident__1` * :n:`Z -> @ident__1` * :n:`Z -> option @ident__1` + * :n:`Decimal.decimal -> @ident__1` + * :n:`Decimal.decimal -> option @ident__1` And the printing function :n:`@ident__3` should have one of the following types: @@ -1468,11 +1469,17 @@ Numeral notations * :n:`@ident__1 -> option Decimal.uint` * :n:`@ident__1 -> Z` * :n:`@ident__1 -> option Z` + * :n:`@ident__1 -> Decimal.decimal` + * :n:`@ident__1 -> option Decimal.decimal` When parsing, the application of the parsing function :n:`@ident__2` to the number will be fully reduced, and universes of the resulting term will be refreshed. + Note that only fully-reduced ground terms (terms containing only + function application, constructors, inductive type families, and + primitive integers) will be considered for printing. + .. cmdv:: Numeral Notation @ident__1 @ident__2 @ident__3 : @scope (warning after @num). When a literal larger than :token:`num` is parsed, a warning @@ -1497,15 +1504,16 @@ Numeral notations The numeral notation registered for :token:`type` does not support the given numeral. This error is given when the interpretation function returns :g:`None`, or if the interpretation is registered - for only non-negative integers, and the given numeral is negative. + only for integers or non-negative integers, and the given numeral + has a fractional or exponent part or is negative. - .. exn:: @ident should go from Decimal.int to @type or (option @type). Instead of Decimal.int, the types Decimal.uint or Z or Int63.int could be used (you may need to require BinNums or Decimal or Int63 first). + .. exn:: @ident should go from Decimal.int to @type or (option @type). Instead of Decimal.int, the types Decimal.uint or Z or Int63.int or Decimal.decimal could be used (you may need to require BinNums or Decimal or Int63 first). The parsing function given to the :cmd:`Numeral Notation` vernacular is not of the right type. - .. exn:: @ident should go from @type to Decimal.int or (option Decimal.int). Instead of Decimal.int, the types Decimal.uint or Z or Int63.int could be used (you may need to require BinNums or Decimal or Int63 first). + .. exn:: @ident should go from @type to Decimal.int or (option Decimal.int). Instead of Decimal.int, the types Decimal.uint or Z or Int63.int or Decimal.decimal could be used (you may need to require BinNums or Decimal or Int63 first). The printing function given to the :cmd:`Numeral Notation` vernacular is not of the right type. @@ -1518,9 +1526,9 @@ Numeral notations .. exn:: Unexpected term @term while parsing a numeral notation. Parsing functions must always return ground terms, made up of - applications of constructors and inductive types. Parsing - functions may not return terms containing axioms, bare - (co)fixpoints, lambdas, etc. + applications of constructors, inductive types, and primitive + integers. Parsing functions may not return terms containing + axioms, bare (co)fixpoints, lambdas, etc. .. exn:: Unexpected non-option term @term while parsing a numeral notation. @@ -1618,6 +1626,10 @@ String notations :n:`@ident__2` to the string will be fully reduced, and universes of the resulting term will be refreshed. + Note that only fully-reduced ground terms (terms containing only + function application, constructors, inductive type families, and + primitive integers) will be considered for printing. + .. exn:: Cannot interpret this string as a value of type @type The string notation registered for :token:`type` does not support @@ -1642,9 +1654,9 @@ String notations .. exn:: Unexpected term @term while parsing a string notation. Parsing functions must always return ground terms, made up of - applications of constructors and inductive types. Parsing - functions may not return terms containing axioms, bare - (co)fixpoints, lambdas, etc. + applications of constructors, inductive types, and primitive + integers. Parsing functions may not return terms containing + axioms, bare (co)fixpoints, lambdas, etc. .. exn:: Unexpected non-option term @term while parsing a string notation. |