diff options
Diffstat (limited to 'doc/sphinx/proof-engine')
| -rw-r--r-- | doc/sphinx/proof-engine/ltac2.rst | 7 | ||||
| -rw-r--r-- | doc/sphinx/proof-engine/vernacular-commands.rst | 73 |
2 files changed, 78 insertions, 2 deletions
diff --git a/doc/sphinx/proof-engine/ltac2.rst b/doc/sphinx/proof-engine/ltac2.rst index c545287fdd..045d028d02 100644 --- a/doc/sphinx/proof-engine/ltac2.rst +++ b/doc/sphinx/proof-engine/ltac2.rst @@ -427,6 +427,8 @@ In general, quotations can be introduced in terms using the following syntax, wh .. prodn:: ltac2_term += @ident : ( @quotentry ) +.. _ltac2_built-in-quotations: + Built-in quotations +++++++++++++++++++ @@ -439,10 +441,11 @@ The current implementation recognizes the following built-in quotations: holes at runtime (type ``Init.constr`` as well). - ``pattern``, which parses Coq patterns and produces a pattern used for term matching (type ``Init.pattern``). -- ``reference``, which parses either a :n:`@qualid` or :n:`& @ident`. Qualified names +- ``reference``, which parses either a :n:`@qualid` or :n:`&@ident`. Qualified names are globalized at internalization into the corresponding global reference, while ``&id`` is turned into ``Std.VarRef id``. This produces at runtime a - ``Std.reference``. + ``Std.reference``. There shall be no white space between the ampersand + symbol (``&``) and the identifier (:n:`@ident`). The following syntactic sugar is provided for two common cases. diff --git a/doc/sphinx/proof-engine/vernacular-commands.rst b/doc/sphinx/proof-engine/vernacular-commands.rst index 774732825a..c391cc949d 100644 --- a/doc/sphinx/proof-engine/vernacular-commands.rst +++ b/doc/sphinx/proof-engine/vernacular-commands.rst @@ -1204,6 +1204,79 @@ Controlling the locality of commands occurs in a section. The :cmd:`Set` and :cmd:`Unset` commands belong to this category. +.. _controlling-typing-flags: + +Controlling Typing Flags +---------------------------- + +.. flag:: Guard Checking + + This option can be used to enable/disable the guard checking of + fixpoints. Warning: this can break the consistency of the system, use at your + own risk. Decreasing argument can still be specified: the decrease is not checked + anymore but it still affects the reduction of the term. Unchecked fixpoints are + printed by :cmd:`Print Assumptions`. + +.. flag:: Positivity Checking + + This option can be used to enable/disable the positivity checking of inductive + types and the productivity checking of coinductive types. Warning: this can + break the consistency of the system, use at your own risk. Unchecked + (co)inductive types are printed by :cmd:`Print Assumptions`. + +.. flag:: Universe Checking + + This option can be used to enable/disable the checking of universes, providing a + form of "type in type". Warning: this breaks the consistency of the system, use + at your own risk. Constants relying on "type in type" are printed by + :cmd:`Print Assumptions`. It has the same effect as `-type-in-type` command line + argument (see :ref:`command-line-options`). + +.. cmd:: Print Typing Flags + + Print the status of the three typing flags: guard checking, positivity checking + and universe checking. + +.. example:: + + .. coqtop:: all reset + + Unset Guard Checking. + + Print Typing Flags. + + Fixpoint f (n : nat) : False + := f n. + + Fixpoint ackermann (m n : nat) {struct m} : nat := + match m with + | 0 => S n + | S m => + match n with + | 0 => ackermann m 1 + | S n => ackermann m (ackermann (S m) n) + end + end. + + Print Assumptions ackermann. + + Note that the proper way to define the Ackermann function is to use + an inner fixpoint: + + .. coqtop:: all reset + + Fixpoint ack m := + fix ackm n := + match m with + | 0 => S n + | S m' => + match n with + | 0 => ack m' 1 + | S n' => ack m' (ackm n') + end + end. + + .. _internal-registration-commands: Internal registration commands |