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diff --git a/doc/sphinx/language/gallina-extensions.rst b/doc/sphinx/language/gallina-extensions.rst index 1d6c11b38..ff5d352c9 100644 --- a/doc/sphinx/language/gallina-extensions.rst +++ b/doc/sphinx/language/gallina-extensions.rst @@ -13,43 +13,42 @@ Extensions of |Gallina| Record types ---------------- -The ``Record`` construction is a macro allowing the definition of +The :cmd:`Record` construction is a macro allowing the definition of records as is done in many programming languages. Its syntax is -described in the grammar below. In fact, the ``Record`` macro is more general +described in the grammar below. In fact, the :cmd:`Record` macro is more general than the usual record types, since it allows also for “manifest” -expressions. In this sense, the ``Record`` construction allows defining +expressions. In this sense, the :cmd:`Record` construction allows defining “signatures”. .. _record_grammar: .. productionlist:: `sentence` - record : `record_keyword` ident [binders] [: sort] := [ident] { [`field` ; … ; `field`] }. + record : `record_keyword` `ident` [ `binders` ] [: `sort` ] := [ `ident` ] { [ `field` ; … ; `field` ] }. record_keyword : Record | Inductive | CoInductive - field : name [binders] : type [ where notation ] - : | name [binders] [: term] := term + field : `ident` [ `binders` ] : `type` [ where `notation` ] + : | `ident` [ `binders` ] [: `type` ] := `term` In the expression: -.. cmd:: Record @ident {* @param } {? : @sort} := {? @ident} { {*; @ident {* @binder } : @term } }. +.. cmd:: Record @ident @binders {? : @sort} := {? @ident} { {*; @ident @binders : @type } } -the first identifier `ident` is the name of the defined record and `sort` is its +the first identifier :token:`ident` is the name of the defined record and :token:`sort` is its type. The optional identifier following ``:=`` is the name of its constructor. If it is omitted, -the default name ``Build_``\ `ident`, where `ident` is the record name, is used. If `sort` is +the default name ``Build_``\ :token:`ident`, where :token:`ident` is the record name, is used. If :token:`sort` is omitted, the default sort is `\Type`. The identifiers inside the brackets are the names of -fields. For a given field `ident`, its type is :g:`forall binder …, term`. +fields. For a given field :token:`ident`, its type is :g:`forall binders, type`. Remark that the type of a particular identifier may depend on a previously-given identifier. Thus the -order of the fields is important. Finally, each `param` is a parameter of the record. +order of the fields is important. Finally, :token:`binders` are parameters of the record. More generally, a record may have explicitly defined (a.k.a. manifest) -fields. For instance, we might have:: - - Record ident param : sort := { ident₁ : type₁ ; ident₂ := term₂ ; ident₃ : type₃ }. - -in which case the correctness of |type_3| may rely on the instance |term_2| of |ident_2| and |term_2| in turn -may depend on |ident_1|. +fields. For instance, we might have: +:n:`Record @ident @binders : @sort := { @ident₁ : @type₁ ; @ident₂ := @term₂ ; @ident₃ : @type₃ }`. +in which case the correctness of :n:`@type₃` may rely on the instance :n:`@term₂` of :n:`@ident₂` and :n:`@term₂` may in turn depend on :n:`@ident₁`. .. example:: + The set of rational numbers may be defined as: + .. coqtop:: reset all Record Rat : Set := mkRat @@ -65,11 +64,10 @@ depends on both ``top`` and ``bottom``. Let us now see the work done by the ``Record`` macro. First the macro generates a variant type definition with just one constructor: +:n:`Variant @ident {? @binders } : @sort := @ident₀ {? @binders }`. -.. cmd:: Variant @ident {* @params} : @sort := @ident {* (@ident : @term_1)}. - -To build an object of type `ident`, one should provide the constructor -|ident_0| with the appropriate number of terms filling the fields of the record. +To build an object of type :n:`@ident`, one should provide the constructor +:n:`@ident₀` with the appropriate number of terms filling the fields of the record. .. example:: Let us define the rational :math:`1/2`: @@ -101,15 +99,15 @@ to be all present if the missing ones can be inferred or prompted for This syntax can be disabled globally for printing by -.. cmd:: Unset Printing Records. +.. cmd:: Unset Printing Records For a given type, one can override this using either -.. cmd:: Add Printing Record @ident. +.. cmd:: Add Printing Record @ident to get record syntax or -.. cmd:: Add Printing Constructor @ident. +.. cmd:: Add Printing Constructor @ident to get constructor syntax. @@ -144,7 +142,7 @@ available: It can be activated for printing with -.. cmd:: Set Printing Projections. +.. opt:: Printing Projections .. example:: @@ -169,7 +167,7 @@ and the syntax `term.(@qualid` |term_1| |term_n| `)` to `@qualid` |term_1| `…` In each case, `term` is the object projected and the other arguments are the parameters of the inductive type. -.. note::. Records defined with the ``Record`` keyword are not allowed to be +.. note:: Records defined with the ``Record`` keyword are not allowed to be recursive (references to the record's name in the type of its field raises an error). To define recursive records, one can use the ``Inductive`` and ``CoInductive`` keywords, resulting in an inductive or co-inductive record. @@ -179,9 +177,9 @@ other arguments are the parameters of the inductive type. .. note:: Induction schemes are automatically generated for inductive records. Automatic generation of induction schemes for non-recursive records defined with the ``Record`` keyword can be activated with the - ``Nonrecursive Elimination Schemes`` option (see :ref:`TODO-13.1.1-nonrecursive-elimination-schemes`). + ``Nonrecursive Elimination Schemes`` option (see :ref:`proofschemes-induction-principles`). -.. note::``Structure`` is a synonym of the keyword ``Record``. +.. note:: ``Structure`` is a synonym of the keyword ``Record``. .. warn:: @ident cannot be defined. @@ -189,9 +187,9 @@ other arguments are the parameters of the inductive type. This message is followed by an explanation of this impossibility. There may be three reasons: - #. The name `ident` already exists in the environment (see Section :ref:`TODO-1.3.1-axioms`). + #. The name `ident` already exists in the environment (see :cmd:`Axiom`). #. The body of `ident` uses an incorrect elimination for - `ident` (see Sections :ref:`TODO-1.3.4-fixpoint` and :ref:`TODO-4.5.3-case-expr`). + `ident` (see :cmd:`Fixpoint` and :ref:`Destructors`). #. The type of the projections `ident` depends on previous projections which themselves could not be defined. @@ -208,16 +206,18 @@ other arguments are the parameters of the inductive type. During the definition of the one-constructor inductive definition, all the errors of inductive definitions, as described in Section -:ref:`TODO-1.3.3-inductive-definitions`, may also occur. +:ref:`gallina-inductive-definitions`, may also occur. -**See also** Coercions and records in Section :ref:`TODO-18.9-coercions-and-records` of the chapter devoted to coercions. +**See also** Coercions and records in Section :ref:`coercions-classes-as-records` of the chapter devoted to coercions. .. _primitive_projections: Primitive Projections ~~~~~~~~~~~~~~~~~~~~~ -The option ``Set Primitive Projections`` turns on the use of primitive +.. opt:: Primitive Projections + +Turns on the use of primitive projections when defining subsequent records (even through the ``Inductive`` and ``CoInductive`` commands). Primitive projections extended the Calculus of Inductive Constructions with a new binary @@ -229,21 +229,27 @@ terms when manipulating parameterized records and typechecking time. On the user level, primitive projections can be used as a replacement for the usual defined ones, although there are a few notable differences. -The internally omitted parameters can be reconstructed at printing time -even though they are absent in the actual AST manipulated by the kernel. This -can be obtained by setting the ``Printing Primitive Projection Parameters`` -flag. Another compatibility printing can be activated thanks to the -``Printing Primitive Projection Compatibility`` option which governs the +.. opt:: Printing Primitive Projection Parameters + +This compatibility option reconstructs internally omitted parameters at +printing time (even though they are absent in the actual AST manipulated +by the kernel). + +.. opt:: Printing Primitive Projection Compatibility + +This compatibility option (on by default) governs the printing of pattern-matching over primitive records. Primitive Record Types ++++++++++++++++++++++ -When the ``Set Primitive Projections`` option is on, definitions of +When the :opt:`Primitive Projections` option is on, definitions of record types change meaning. When a type is declared with primitive projections, its :g:`match` construct is disabled (see :ref:`primitive_projections` though). To eliminate the (co-)inductive type, one must use its defined primitive projections. +.. The following paragraph is quite redundant with what is above + For compatibility, the parameters still appear to the user when printing terms even though they are absent in the actual AST manipulated by the kernel. This can be changed by unsetting the @@ -304,7 +310,7 @@ printed back as :g:`match` constructs. Variants and extensions of :g:`match` ------------------------------------- -.. _extended pattern-matching: +.. _mult-match: Multiple and nested pattern-matching ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -316,10 +322,11 @@ patterns are allowed, as in ML-like languages. The extension just acts as a macro that is expanded during parsing into a sequence of match on simple patterns. Especially, a construction defined using the extended match is generally printed -under its expanded form (see ``Set Printing Matching`` in :ref:`controlling-match-pp`). +under its expanded form (see :opt:`Printing Matching`). -See also: :ref:`extended pattern-matching`. +See also: :ref:`extendedpatternmatching`. +.. _if-then-else: Pattern-matching on boolean values: the if expression ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -366,6 +373,7 @@ we have the following equivalence Notice that the printing uses the :g:`if` syntax because `sumbool` is declared as such (see :ref:`controlling-match-pp`). +.. _irrefutable-patterns: Irrefutable patterns: the destructuring let variants ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -462,116 +470,63 @@ of :g:`match` expressions. Printing nested patterns +++++++++++++++++++++++++ +.. opt:: Printing Matching + The Calculus of Inductive Constructions knows pattern-matching only over simple patterns. It is however convenient to re-factorize nested pattern-matching into a single pattern-matching over a nested -pattern. |Coq|’s printer tries to do such limited re-factorization. - -.. cmd:: Set Printing Matching. +pattern. -This tells |Coq| to try to use nested patterns. This is the default -behavior. +When this option is on (default), |Coq|’s printer tries to do such +limited re-factorization. +Turning it off tells |Coq| to print only simple pattern-matching problems +in the same way as the |Coq| kernel handles them. -.. cmd:: Unset Printing Matching. - -This tells |Coq| to print only simple pattern-matching problems in the -same way as the |Coq| kernel handles them. - -.. cmd:: Test Printing Matching. - -This tells if the printing matching mode is on or off. The default is -on. Factorization of clauses with same right-hand side ++++++++++++++++++++++++++++++++++++++++++++++++++ +.. opt:: Printing Factorizable Match Patterns + When several patterns share the same right-hand side, it is additionally possible to share the clauses using disjunctive patterns. Assuming that the -printing matching mode is on, whether |Coq|'s printer shall try to do this kind -of factorization is governed by the following commands: - -.. cmd:: Set Printing Factorizable Match Patterns. - -This tells |Coq|'s printer to try to use disjunctive patterns. This is the -default behavior. - -.. cmd:: Unset Printing Factorizable Match Patterns. - -This tells |Coq|'s printer not to try to use disjunctive patterns. - -.. cmd:: Test Printing Factorizable Match Patterns. - -This tells if the factorization of clauses with same right-hand side is on or -off. +printing matching mode is on, this option (on by default) tells |Coq|'s +printer to try to do this kind of factorization. Use of a default clause +++++++++++++++++++++++ +.. opt:: Printing Allow Default Clause + When several patterns share the same right-hand side which do not depend on the arguments of the patterns, yet an extra factorization is possible: the disjunction of patterns can be replaced with a `_` default clause. Assuming that -the printing matching mode and the factorization mode are on, whether |Coq|'s -printer shall try to use a default clause is governed by the following commands: - -.. cmd:: Set Printing Allow Default Clause. - -This tells |Coq|'s printer to use a default clause when relevant. This is the -default behavior. - -.. cmd:: Unset Printing Allow Default Clause. - -This tells |Coq|'s printer not to use a default clause. - -.. cmd:: Test Printing Allow Default Clause. - -This tells if the use of a default clause is allowed. +the printing matching mode and the factorization mode are on, this option (on by +default) tells |Coq|'s printer to use a default clause when relevant. Printing of wildcard patterns ++++++++++++++++++++++++++++++ -Some variables in a pattern may not occur in the right-hand side of -the pattern-matching clause. There are options to control the display -of these variables. - -.. cmd:: Set Printing Wildcard. +.. opt:: Printing Wildcard -The variables having no occurrences in the right-hand side of the +Some variables in a pattern may not occur in the right-hand side of +the pattern-matching clause. When this option is on (default), the +variables having no occurrences in the right-hand side of the pattern-matching clause are just printed using the wildcard symbol “_”. -.. cmd:: Unset Printing Wildcard. - -The variables, even useless, are printed using their usual name. But -some non-dependent variables have no name. These ones are still -printed using a “_”. - -.. cmd:: Test Printing Wildcard. - -This tells if the wildcard printing mode is on or off. The default is -to print wildcard for useless variables. - Printing of the elimination predicate +++++++++++++++++++++++++++++++++++++ +.. opt:: Printing Synth + In most of the cases, the type of the result of a matched term is mechanically synthesizable. Especially, if the result type does not -depend of the matched term. - -.. cmd:: Set Printing Synth. - -The result type is not printed when |Coq| knows that it can re- +depend of the matched term. When this option is on (default), +the result type is not printed when |Coq| knows that it can re- synthesize it. -.. cmd:: Unset Printing Synth. - -This forces the result type to be always printed. - -.. cmd:: Test Printing Synth. - -This tells if the non-printing of synthesizable types is on or off. -The default is to not print synthesizable types. - Printing matching on irrefutable patterns ++++++++++++++++++++++++++++++++++++++++++ @@ -579,23 +534,23 @@ Printing matching on irrefutable patterns If an inductive type has just one constructor, pattern-matching can be written using the first destructuring let syntax. -.. cmd:: Add Printing Let @ident. +.. cmd:: Add Printing Let @ident This adds `ident` to the list of inductive types for which pattern-matching is written using a let expression. -.. cmd:: Remove Printing Let @ident. +.. cmd:: Remove Printing Let @ident This removes ident from this list. Note that removing an inductive type from this list has an impact only for pattern-matching written using :g:`match`. Pattern-matching explicitly written using a destructuring :g:`let` are not impacted. -.. cmd:: Test Printing Let for @ident. +.. cmd:: Test Printing Let for @ident This tells if `ident` belongs to the list. -.. cmd:: Print Table Printing Let. +.. cmd:: Print Table Printing Let This prints the list of inductive types for which pattern-matching is written using a let expression. @@ -611,20 +566,20 @@ Printing matching on booleans If an inductive type is isomorphic to the boolean type, pattern-matching can be written using ``if`` … ``then`` … ``else`` …: -.. cmd:: Add Printing If @ident. +.. cmd:: Add Printing If @ident This adds ident to the list of inductive types for which pattern-matching is written using an if expression. -.. cmd:: Remove Printing If @ident. +.. cmd:: Remove Printing If @ident This removes ident from this list. -.. cmd:: Test Printing If for @ident. +.. cmd:: Test Printing If for @ident This tells if ident belongs to the list. -.. cmd:: Print Table Printing If. +.. cmd:: Print Table Printing If This prints the list of inductive types for which pattern-matching is written using an if expression. @@ -662,12 +617,12 @@ Advanced recursive functions The following experimental command is available when the ``FunInd`` library has been loaded via ``Require Import FunInd``: -.. cmd:: Function @ident {* @binder} { @decrease_annot } : @type := @term. +.. cmd:: Function @ident {* @binder} { @decrease_annot } : @type := @term This command can be seen as a generalization of ``Fixpoint``. It is actually a wrapper for several ways of defining a function *and other useful related objects*, namely: an induction principle that reflects the recursive -structure of the function (see Section :ref:`TODO-8.5.5-functional-induction`) and its fixpoint equality. +structure of the function (see :tacn:`function induction`) and its fixpoint equality. The meaning of this declaration is to define a function ident, similarly to ``Fixpoint`. Like in ``Fixpoint``, the decreasing argument must be given (unless the function is not recursive), but it might not @@ -680,8 +635,8 @@ The ``Function`` construction also enjoys the ``with`` extension to define mutually recursive definitions. However, this feature does not work for non structurally recursive functions. -See the documentation of functional induction (:ref:`TODO-8.5.5-functional-induction`) -and ``Functional Scheme`` (:ref:`TODO-13.2-functional-scheme`) for how to use +See the documentation of functional induction (:tacn:`function induction`) +and ``Functional Scheme`` (:ref:`functional-scheme`) for how to use the induction principle to easily reason about the function. Remark: To obtain the right principle, it is better to put rigid @@ -729,11 +684,11 @@ presence of partial application of `wrong` in the body of For now, dependent cases are not treated for non structurally terminating functions. -.. exn:: The recursive argument must be specified -.. exn:: No argument name @ident -.. exn:: Cannot use mutual definition with well-founded recursion or measure +.. exn:: The recursive argument must be specified. +.. exn:: No argument name @ident. +.. exn:: Cannot use mutual definition with well-founded recursion or measure. -.. warn:: Cannot define graph for @ident +.. warn:: Cannot define graph for @ident. The generation of the graph relation (`R_ident`) used to compute the induction scheme of ident raised a typing error. Only `ident` is defined; the induction scheme @@ -743,16 +698,16 @@ terminating functions. which ``Function`` cannot deal with yet. - the definition is not a *pattern-matching tree* as explained above. -.. warn:: Cannot define principle(s) for @ident +.. warn:: Cannot define principle(s) for @ident. The generation of the graph relation (`R_ident`) succeeded but the induction principle could not be built. Only `ident` is defined. Please report. -.. warn:: Cannot build functional inversion principle +.. warn:: Cannot build functional inversion principle. `functional inversion` will not be available for the function. -See also: :ref:`TODO-13.2-generating-ind-principles` and ref:`TODO-8.5.5-functional-induction` +See also: :ref:`functional-scheme` and :tacn:`function induction` Depending on the ``{…}`` annotation, different definition mechanisms are used by ``Function``. A more precise description is given below. @@ -763,7 +718,7 @@ used by ``Function``. A more precise description is given below. the following are defined: + `ident_rect`, `ident_rec` and `ident_ind`, which reflect the pattern - matching structure of `term` (see the documentation of :ref:`TODO-1.3.3-Inductive`); + matching structure of `term` (see :cmd:`Inductive`); + The inductive `R_ident` corresponding to the graph of `ident` (silently); + `ident_complete` and `ident_correct` which are inversion information linking the function and its graph. @@ -812,21 +767,22 @@ used by ``Function``. A more precise description is given below. hand. Remark: Proof obligations are presented as several subgoals belonging to a Lemma `ident`\ :math:`_{\sf tcc}`. +.. _section-mechanism: Section mechanism ----------------- The sectioning mechanism can be used to to organize a proof in structured sections. Then local declarations become available (see -Section :ref:`TODO-1.3.2-Definitions`). +Section :ref:`gallina-definitions`). -.. cmd:: Section @ident. +.. cmd:: Section @ident This command is used to open a section named `ident`. -.. cmd:: End @ident. +.. cmd:: End @ident This command closes the section named `ident`. After closing of the section, the local declarations (variables and local definitions) get @@ -859,7 +815,7 @@ Section :ref:`TODO-1.3.2-Definitions`). Notice the difference between the value of `x’` and `x’’` inside section `s1` and outside. - .. exn:: This is not the last opened section + .. exn:: This is not the last opened section. **Remarks:** @@ -888,44 +844,44 @@ together, as well as a means of massive abstraction. In the syntax of module application, the ! prefix indicates that any `Inline` directive in the type of the functor arguments will be ignored -(see :ref:`named_module_type` below). +(see the ``Module Type`` command below). -.. cmd:: Module @ident. +.. cmd:: Module @ident This command is used to start an interactive module named `ident`. -.. cmdv:: Module @ident {* @module_binding}. +.. cmdv:: Module @ident {* @module_binding} Starts an interactive functor with parameters given by module_bindings. -.. cmdv:: Module @ident : @module_type. +.. cmdv:: Module @ident : @module_type Starts an interactive module specifying its module type. -.. cmdv:: Module @ident {* @module_binding} : @module_type. +.. cmdv:: Module @ident {* @module_binding} : @module_type Starts an interactive functor with parameters given by the list of `module binding`, and output module type `module_type`. -.. cmdv:: Module @ident <: {+<: @module_type }. +.. cmdv:: Module @ident <: {+<: @module_type } Starts an interactive module satisfying each `module_type`. - .. cmdv:: Module @ident {* @module_binding} <: {+<; @module_type }. + .. cmdv:: Module @ident {* @module_binding} <: {+<: @module_type }. Starts an interactive functor with parameters given by the list of `module_binding`. The output module type is verified against each `module_type`. -.. cmdv:: Module [ Import | Export ]. +.. cmdv:: Module [ Import | Export ] Behaves like ``Module``, but automatically imports or exports the module. Reserved commands inside an interactive module ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -.. cmd:: Include @module. +.. cmd:: Include @module Includes the content of module in the current interactive module. Here module can be a module expression or a module @@ -933,11 +889,11 @@ Reserved commands inside an interactive module expression then the system tries to instantiate module by the current interactive module. -.. cmd:: Include {+<+ @module}. +.. cmd:: Include {+<+ @module} is a shortcut for the commands ``Include`` `module` for each `module`. -.. cmd:: End @ident. +.. cmd:: End @ident This command closes the interactive module `ident`. If the module type was given the content of the module is matched against it and an error @@ -945,42 +901,40 @@ Reserved commands inside an interactive module functor) its components (constants, inductive types, submodules etc.) are now available through the dot notation. - .. exn:: No such label @ident + .. exn:: No such label @ident. - .. exn:: Signature components for label @ident do not match + .. exn:: Signature components for label @ident do not match. - .. exn:: This is not the last opened module + .. exn:: This is not the last opened module. -.. cmd:: Module @ident := @module_expression. +.. cmd:: Module @ident := @module_expression This command defines the module identifier `ident` to be equal to `module_expression`. - .. cmdv:: Module @ident {* @module_binding} := @module_expression. + .. cmdv:: Module @ident {* @module_binding} := @module_expression Defines a functor with parameters given by the list of `module_binding` and body `module_expression`. - .. cmdv:: Module @ident {* @module_binding} : @module_type := @module_expression. + .. cmdv:: Module @ident {* @module_binding} : @module_type := @module_expression Defines a functor with parameters given by the list of `module_binding` (possibly none), and output module type `module_type`, with body `module_expression`. - .. cmdv:: Module @ident {* @module_binding} <: {+<: @module_type} := @module_expression. + .. cmdv:: Module @ident {* @module_binding} <: {+<: @module_type} := @module_expression Defines a functor with parameters given by module_bindings (possibly none) with body `module_expression`. The body is checked against each |module_type_i|. - .. cmdv:: Module @ident {* @module_binding} := {+<+ @module_expression}. + .. cmdv:: Module @ident {* @module_binding} := {+<+ @module_expression} is equivalent to an interactive module where each `module_expression` is included. -.. _named_module_type: - -.. cmd:: Module Type @ident. +.. cmd:: Module Type @ident This command is used to start an interactive module type `ident`. - .. cmdv:: Module Type @ident {* @module_binding}. + .. cmdv:: Module Type @ident {* @module_binding} Starts an interactive functor type with parameters given by `module_bindings`. @@ -988,43 +942,44 @@ This command is used to start an interactive module type `ident`. Reserved commands inside an interactive module type: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -.. cmd:: Include @module. +.. cmd:: Include @module Same as ``Include`` inside a module. -.. cmd:: Include {+<+ @module}. +.. cmd:: Include {+<+ @module} is a shortcut for the command ``Include`` `module` for each `module`. -.. cmd:: @assumption_keyword Inline @assums. +.. cmd:: @assumption_keyword Inline @assums + :name: Inline The instance of this assumption will be automatically expanded at functor application, except when this functor application is prefixed by a ``!`` annotation. -.. cmd:: End @ident. +.. cmd:: End @ident This command closes the interactive module type `ident`. - .. exn:: This is not the last opened module type + .. exn:: This is not the last opened module type. -.. cmd:: Module Type @ident := @module_type. +.. cmd:: Module Type @ident := @module_type Defines a module type `ident` equal to `module_type`. - .. cmdv:: Module Type @ident {* @module_binding} := @module_type. + .. cmdv:: Module Type @ident {* @module_binding} := @module_type Defines a functor type `ident` specifying functors taking arguments `module_bindings` and returning `module_type`. - .. cmdv:: Module Type @ident {* @module_binding} := {+<+ @module_type }. + .. cmdv:: Module Type @ident {* @module_binding} := {+<+ @module_type } is equivalent to an interactive module type were each `module_type` is included. -.. cmd:: Declare Module @ident : @module_type. +.. cmd:: Declare Module @ident : @module_type Declares a module `ident` of type `module_type`. - .. cmdv:: Declare Module @ident {* @module_binding} : @module_type. + .. cmdv:: Declare Module @ident {* @module_binding} : @module_type Declares a functor with parameters given by the list of `module_binding` and output module type `module_type`. @@ -1188,107 +1143,107 @@ some of the fields and give one of its possible implementations: Notice that ``M`` is a correct body for the component ``M2`` since its ``T`` component is equal ``nat`` and hence ``M1.T`` as specified. -**Remarks:** +.. note:: -#. Modules and module types can be nested components of each other. -#. One can have sections inside a module or a module type, but not a - module or a module type inside a section. -#. Commands like ``Hint`` or ``Notation`` can also appear inside modules and - module types. Note that in case of a module definition like: + #. Modules and module types can be nested components of each other. + #. One can have sections inside a module or a module type, but not a + module or a module type inside a section. + #. Commands like ``Hint`` or ``Notation`` can also appear inside modules and + module types. Note that in case of a module definition like: -:: + :: - Module N : SIG := M. + Module N : SIG := M. -or:: + or:: - Module N : SIG. … End N. + Module N : SIG. … End N. -hints and the like valid for ``N`` are not those defined in ``M`` (or the module body) but the ones defined -in ``SIG``. + hints and the like valid for ``N`` are not those defined in ``M`` + (or the module body) but the ones defined in ``SIG``. .. _import_qualid: -.. cmd:: Import @qualid. +.. cmd:: Import @qualid If `qualid` denotes a valid basic module (i.e. its module type is a signature), makes its components available by their short names. -.. example:: + .. example:: - .. coqtop:: reset all + .. coqtop:: reset all - Module Mod. + Module Mod. - Definition T:=nat. + Definition T:=nat. - Check T. + Check T. - End Mod. + End Mod. - Check Mod.T. + Check Mod.T. - Fail Check T. + Fail Check T. - Import Mod. + Import Mod. - Check T. + Check T. -Some features defined in modules are activated only when a module is -imported. This is for instance the case of notations (see :ref:`TODO-12.1-Notations`). + Some features defined in modules are activated only when a module is + imported. This is for instance the case of notations (see :ref:`Notations`). -Declarations made with the Local flag are never imported by theImport -command. Such declarations are only accessible through their fully -qualified name. + Declarations made with the ``Local`` flag are never imported by the :cmd:`Import` + command. Such declarations are only accessible through their fully + qualified name. -.. example:: + .. example:: - .. coqtop:: all + .. coqtop:: all - Module A. + Module A. - Module B. + Module B. - Local Definition T := nat. + Local Definition T := nat. - End B. + End B. - End A. + End A. - Import A. + Import A. - Fail Check B.T. + Fail Check B.T. .. cmdv:: Export @qualid + :name: Export When the module containing the command Export qualid is imported, qualid is imported as well. - .. exn:: @qualid is not a module + .. exn:: @qualid is not a module. .. warn:: Trying to mask the absolute name @qualid! -.. cmd:: Print Module @ident. +.. cmd:: Print Module @ident - Prints the module type and (optionally) the body of the module `ident`. + Prints the module type and (optionally) the body of the module :n:`@ident`. -.. cmd:: Print Module Type @ident. +.. cmd:: Print Module Type @ident - Prints the module type corresponding to `ident`. + Prints the module type corresponding to :n:`@ident`. .. opt:: Short Module Printing - This option (off by default) disables the printing of the types of fields, - leaving only their names, for the commands ``Print Module`` and ``Print Module Type``. - -.. cmd:: Locate Module @qualid. - - Prints the full name of the module `qualid`. + This option (off by default) disables the printing of the types of fields, + leaving only their names, for the commands :cmd:`Print Module` and + :cmd:`Print Module Type`. Libraries and qualified names --------------------------------- +.. _names-of-libraries: + Names of libraries ~~~~~~~~~~~~~~~~~~ @@ -1296,15 +1251,16 @@ The theories developed in |Coq| are stored in *library files* which are hierarchically classified into *libraries* and *sublibraries*. To express this hierarchy, library names are represented by qualified identifiers qualid, i.e. as list of identifiers separated by dots (see -:ref:`TODO-1.2.3-identifiers`). For instance, the library file ``Mult`` of the standard +:ref:`gallina-identifiers`). For instance, the library file ``Mult`` of the standard |Coq| library ``Arith`` is named ``Coq.Arith.Mult``. The identifier that starts the name of a library is called a *library root*. All library files of the standard library of |Coq| have the reserved root |Coq| but library file names based on other roots can be obtained by using |Coq| commands -(coqc, coqtop, coqdep, …) options ``-Q`` or ``-R`` (see :ref:`TODO-14.3.3-command-line-options`). +(coqc, coqtop, coqdep, …) options ``-Q`` or ``-R`` (see :ref:`command-line-options`). Also, when an interactive |Coq| session starts, a library of root ``Top`` is -started, unless option ``-top`` or ``-notop`` is set (see :ref:`TODO-14.3.3-command-line-options`). +started, unless option ``-top`` or ``-notop`` is set (see :ref:`command-line-options`). +.. _qualified-names: Qualified names ~~~~~~~~~~~~~~~ @@ -1339,13 +1295,13 @@ names also applies to library file names. |Coq| maintains a table called the name table which maps partially qualified names of constructions to absolute names. This table is updated by the -commands ``Require`` (see :ref:`TODO-6.5.1-Require`), Import and Export (see :ref:`import_qualid`) and +commands :cmd:`Require`, :cmd:`Import` and :cmd:`Export` and also each time a new declaration is added to the context. An absolute name is called visible from a given short or partially qualified name when this latter name is enough to denote it. This means that the short or partially qualified name is mapped to the absolute name in |Coq| name table. Definitions flagged as Local are only accessible with -their fully qualified name (see :ref:`TODO-1.3.2-definitions`). +their fully qualified name (see :ref:`gallina-definitions`). It may happen that a visible name is hidden by the short name or a qualified name of another construction. In this case, the name that @@ -1367,16 +1323,15 @@ accessible, absolute names can never be hidden. Locate nat. -See also: Command Locate in :ref:`TODO-6.3.10-locate-qualid` and Locate Library in -:ref:`TODO-6.6.11-locate-library`. +See also: Commands :cmd:`Locate` and :cmd:`Locate Library`. +.. _libraries-and-filesystem: Libraries and filesystem ~~~~~~~~~~~~~~~~~~~~~~~~ -Please note that the questions described here have been subject to -redesign in |Coq| v8.5. Former versions of |Coq| use the same terminology -to describe slightly different things. +.. note:: The questions described here have been subject to redesign in |Coq| 8.5. + Former versions of |Coq| use the same terminology to describe slightly different things. Compiled files (``.vo`` and ``.vio``) store sub-libraries. In order to refer to them inside |Coq|, a translation from file-system names to |Coq| names @@ -1412,7 +1367,7 @@ translation and with an empty logical prefix. The command line option ``-R`` is a variant of ``-Q`` which has the strictly same behavior regarding loadpaths, but which also makes the corresponding ``.vo`` files available through their short names in a way -not unlike the ``Import`` command (see :ref:`import_qualid`). For instance, ``-R`` `path` ``Lib`` +not unlike the ``Import`` command (see :ref:`here <import_qualid>`). For instance, ``-R`` `path` ``Lib`` associates to the ``filepath/fOO/Bar/File.vo`` the logical name ``Lib.fOO.Bar.File``, but allows this file to be accessed through the short names ``fOO.Bar.File,Bar.File`` and ``File``. If several files with @@ -1420,7 +1375,7 @@ identical base name are present in different subdirectories of a recursive loadpath, which of these files is found first may be system- dependent and explicit qualification is recommended. The ``From`` argument of the ``Require`` command can be used to bypass the implicit shortening -by providing an absolute root to the required file (see :ref:`TODO-6.5.1-require-qualid`). +by providing an absolute root to the required file (see :ref:`compiled-files`). There also exists another independent loadpath mechanism attached to OCaml object files (``.cmo`` or ``.cmxs``) rather than |Coq| object @@ -1428,11 +1383,12 @@ files as described above. The OCaml loadpath is managed using the option ``-I`` `path` (in the OCaml world, there is neither a notion of logical name prefix nor a way to access files in subdirectories of path). See the command ``Declare`` ``ML`` ``Module`` in -:ref:`TODO-6.5-compiled-files` to understand the need of the OCaml loadpath. +:ref:`compiled-files` to understand the need of the OCaml loadpath. -See :ref:`TODO-14.3.3-command-line-options` for a more general view over the |Coq| command +See :ref:`command-line-options` for a more general view over the |Coq| command line options. +.. _ImplicitArguments: Implicit arguments ------------------ @@ -1477,7 +1433,9 @@ For instance, the first argument of in module ``List.v`` is strict because :g:`list` is an inductive type and :g:`A` will always be inferable from the type :g:`list A` of the third argument of -:g:`cons`. On the contrary, the second argument of a term of type +:g:`cons`. Also, the first argument of :g:`cons` is strict with respect to the second one, +since the first argument is exactly the type of the second argument. +On the contrary, the second argument of a term of type :: forall P:nat->Prop, forall n:nat, P n -> ex nat P @@ -1548,10 +1506,9 @@ inserted. In the second case, the function is considered to be implicitly applied to the implicit arguments it is waiting for: one says that the implicit argument is maximally inserted. -Each implicit argument can be declared to have to be inserted -maximally or non maximally. This can be governed argument per argument -by the command ``Implicit Arguments`` (see Section :ref:`declare-implicit-args`) or globally by the -command ``Set Maximal Implicit Insertion`` (see Section :ref:`controlling-insertion-implicit-args`). +Each implicit argument can be declared to have to be inserted maximally or non +maximally. This can be governed argument per argument by the command +:cmd:`Arguments (implicits)` or globally by the :opt:`Maximal Implicit Insertion` option. See also :ref:`displaying-implicit-args`. @@ -1564,6 +1521,7 @@ force the given argument to be guessed by replacing it by “_”. If possible, the correct argument will be automatically generated. .. exn:: Cannot infer a term for this placeholder. + :name: Cannot infer a term for this placeholder. (Casual use of implicit arguments) |Coq| was not able to deduce an instantiation of a “_”. @@ -1603,7 +1561,7 @@ absent in every situation but still be able to specify it if needed: The syntax is supported in all top-level definitions: -``Definition``, ``Fixpoint``, ``Lemma`` and so on. For (co-)inductive datatype +:cmd:`Definition`, :cmd:`Fixpoint`, :cmd:`Lemma` and so on. For (co-)inductive datatype declarations, the semantics are the following: an inductive parameter declared as an implicit argument need not be repeated in the inductive definition but will become implicit for the constructors of the @@ -1626,7 +1584,8 @@ Declaring Implicit Arguments To set implicit arguments *a posteriori*, one can use the command: -.. cmd:: Arguments @qualid {* @possibly_bracketed_ident }. +.. cmd:: Arguments @qualid {* @possibly_bracketed_ident } + :name: Arguments (implicits) where the list of `possibly_bracketed_ident` is a prefix of the list of arguments of `qualid` where the ones to be declared implicit are @@ -1639,7 +1598,7 @@ of `qualid`. Implicit arguments can be cleared with the following syntax: -.. cmd:: Arguments @qualid : clear implicits. +.. cmd:: Arguments @qualid : clear implicits .. cmdv:: Global Arguments @qualid {* @possibly_bracketed_ident } @@ -1648,13 +1607,13 @@ Implicit arguments can be cleared with the following syntax: implicit arguments known from inside the section to be the ones declared by the command. -.. cmdv:: Local Arguments @qualid {* @possibly_bracketed_ident }. +.. cmdv:: Local Arguments @qualid {* @possibly_bracketed_ident } When in a module, tell not to activate the implicit arguments ofqualid declared by this command to contexts that require the module. -.. cmdv:: {? Global | Local } Arguments @qualid {*, {+ @possibly_bracketed_ident } }. +.. cmdv:: {? Global | Local } Arguments @qualid {*, {+ @possibly_bracketed_ident } } For names of constants, inductive types, constructors, lemmas which can only be applied to a fixed number of @@ -1706,7 +1665,7 @@ Automatic declaration of implicit arguments |Coq| can also automatically detect what are the implicit arguments of a defined object. The command is just -.. cmd:: Arguments @qualid : default implicits. +.. cmd:: Arguments @qualid : default implicits The auto-detection is governed by options telling if strict, contextual, or reversible-pattern implicit arguments must be @@ -1780,14 +1739,10 @@ appear strictly in the body of the type, they are implicit. Mode for automatic declaration of implicit arguments ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -In case one wants to systematically declare implicit the arguments -detectable as such, one may switch to the automatic declaration of -implicit arguments mode by using the command: - -.. cmd:: Set Implicit Arguments. +.. opt:: Implicit Arguments -Conversely, one may unset the mode by using ``Unset Implicit Arguments``. -The mode is off by default. Auto-detection of implicit arguments is +This option (off by default) allows to systematically declare implicit +the arguments detectable as such. Auto-detection of implicit arguments is governed by options controlling whether strict and contextual implicit arguments have to be considered or not. @@ -1796,76 +1751,55 @@ arguments have to be considered or not. Controlling strict implicit arguments ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.. opt:: Strict Implicit + When the mode for automatic declaration of implicit arguments is on, the default is to automatically set implicit only the strict implicit arguments plus, for historical reasons, a small subset of the non-strict implicit arguments. To relax this constraint and to set -implicit all non strict implicit arguments by default, use the command: - -.. cmd:: Unset Strict Implicit. +implicit all non strict implicit arguments by default, you can turn this +option off. -Conversely, use the command ``Set Strict Implicit`` to restore the -original mode that declares implicit only the strict implicit -arguments plus a small subset of the non strict implicit arguments. +.. opt:: Strongly Strict Implicit -In the other way round, to capture exactly the strict implicit -arguments and no more than the strict implicit arguments, use the -command - -.. cmd:: Set Strongly Strict Implicit. - -Conversely, use the command ``Unset Strongly Strict Implicit`` to let the -option “Strict Implicit” decide what to do. - -Remark: In versions of |Coq| prior to version 8.0, the default was to -declare the strict implicit arguments as implicit. +Use this option (off by default) to capture exactly the strict implicit +arguments and no more than the strict implicit arguments. .. _controlling-contextual-implicit-args: Controlling contextual implicit arguments ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -By default, |Coq| does not automatically set implicit the contextual -implicit arguments. To tell |Coq| to infer also contextual implicit -argument, use command - -.. cmd:: Set Contextual Implicit. +.. opt:: Contextual Implicit -Conversely, use command ``Unset Contextual Implicit`` to unset the -contextual implicit mode. +By default, |Coq| does not automatically set implicit the contextual +implicit arguments. You can turn this option on to tell |Coq| to also +infer contextual implicit argument. .. _controlling-rev-pattern-implicit-args: Controlling reversible-pattern implicit arguments ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -By default, |Coq| does not automatically set implicit the reversible-pattern -implicit arguments. To tell |Coq| to infer also reversible- -pattern implicit argument, use command - -.. cmd:: Set Reversible Pattern Implicit. +.. opt:: Reversible Pattern Implicit -Conversely, use command ``Unset Reversible Pattern Implicit`` to unset the -reversible-pattern implicit mode. +By default, |Coq| does not automatically set implicit the reversible-pattern +implicit arguments. You can turn this option on to tell |Coq| to also infer +reversible-pattern implicit argument. .. _controlling-insertion-implicit-args: Controlling the insertion of implicit arguments not followed by explicit arguments ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -Implicit arguments can be declared to be automatically inserted when a -function is partially applied and the next argument of the function is -an implicit one. In case the implicit arguments are automatically -declared (with the command ``Set Implicit Arguments``), the command - -.. cmd:: Set Maximal Implicit Insertion. +.. opt:: Maximal Implicit Insertion -is used to tell to declare the implicit arguments with a maximal -insertion status. By default, automatically declared implicit -arguments are not declared to be insertable maximally. To restore the -default mode for maximal insertion, use the command +Assuming the implicit argument mode is on, this option (off by default) +declares implicit arguments to be automatically inserted when a +function is partially applied and the next argument of the function is +an implicit one. -.. cmd:: Unset Maximal Implicit Insertion. +.. _explicit-applications: Explicit applications ~~~~~~~~~~~~~~~~~~~~~ @@ -1904,7 +1838,7 @@ Renaming implicit arguments Implicit arguments names can be redefined using the following syntax: -.. cmd:: Arguments @qualid {* @name} : @rename. +.. cmd:: Arguments @qualid {* @name} : @rename With the assert flag, ``Arguments`` can be used to assert that a given object has the expected number of arguments and that these arguments @@ -1930,33 +1864,25 @@ Displaying what the implicit arguments are To display the implicit arguments associated to an object, and to know if each of them is to be used maximally or not, use the command -.. cmd:: Print Implicit @qualid. +.. cmd:: Print Implicit @qualid Explicit displaying of implicit arguments for pretty-printing ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -By default the basic pretty-printing rules hide the inferable implicit -arguments of an application. To force printing all implicit arguments, -use command - -.. cmd:: Set Printing Implicit. +.. opt:: Printing Implicit -Conversely, to restore the hiding of implicit arguments, use command +By default, the basic pretty-printing rules hide the inferable implicit +arguments of an application. Turn this option on to force printing all +implicit arguments. -.. cmd:: Unset Printing Implicit. +.. opt:: Printing Implicit Defensive -By default the basic pretty-printing rules display the implicit +By default, the basic pretty-printing rules display the implicit arguments that are not detected as strict implicit arguments. This “defensive” mode can quickly make the display cumbersome so this can -be deactivated by using the command - -.. cmd:: Unset Printing Implicit Defensive. +be deactivated by turning this option off. -Conversely, to force the display of non strict arguments, use command - -.. cmd:: Set Printing Implicit Defensive. - -See also: ``Set Printing All`` in :ref:`printing_constructions_full`. +See also: :opt:`Printing All`. Interaction with subtyping ~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -1981,17 +1907,14 @@ but succeeds in Deactivation of implicit arguments for parsing ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -Use of implicit arguments can be deactivated by issuing the command: +.. opt:: Parsing Explicit -.. cmd:: Set Parsing Explicit. +Turning this option on (it is off by default) deactivates the use of implicit arguments. In this case, all arguments of constants, inductive types, constructors, etc, including the arguments declared as implicit, have -to be given as if none arguments were implicit. By symmetry, this also -affects printing. To restore parsing and normal printing of implicit -arguments, use: - -.. cmd:: Unset Parsing Explicit. +to be given as if no arguments were implicit. By symmetry, this also +affects printing. Canonical structures ~~~~~~~~~~~~~~~~~~~~ @@ -2006,7 +1929,7 @@ Assume that `qualid` denotes an object ``(Build_struc`` |c_1| … |c_n| ``)`` in structure *struct* of which the fields are |x_1|, …, |x_n|. Assume that `qualid` is declared as a canonical structure using the command -.. cmd:: Canonical Structure @qualid. +.. cmd:: Canonical Structure @qualid Then, each time an equation of the form ``(``\ |x_i| ``_)`` |eq_beta_delta_iota_zeta| |c_i| has to be solved during the type-checking process, `qualid` is used as a solution. @@ -2047,11 +1970,11 @@ and ``B`` can be synthesized in the next statement. Remark: If a same field occurs in several canonical structure, then only the structure declared first as canonical is considered. -.. cmdv:: Canonical Structure @ident := @term : @type. +.. cmdv:: Canonical Structure @ident := @term : @type -.. cmdv:: Canonical Structure @ident := @term. +.. cmdv:: Canonical Structure @ident := @term -.. cmdv:: Canonical Structure @ident : @type := @term. +.. cmdv:: Canonical Structure @ident : @type := @term These are equivalent to a regular definition of `ident` followed by the declaration ``Canonical Structure`` `ident`. @@ -2079,7 +2002,7 @@ It is possible to bind variable names to a given type (e.g. in a development using arithmetic, it may be convenient to bind the names `n` or `m` to the type ``nat`` of natural numbers). The command for that is -.. cmd:: Implicit Types {+ @ident } : @type. +.. cmd:: Implicit Types {+ @ident } : @type The effect of the command is to automatically set the type of bound variables starting with `ident` (either `ident` itself or `ident` followed by @@ -2101,7 +2024,7 @@ case, this latter type is considered). Lemma cons_inj_bool : forall (m n:bool) l, n :: l = m :: l -> n = m. -.. cmdv:: Implicit Type @ident : @type. +.. cmdv:: Implicit Type @ident : @type This is useful for declaring the implicit type of a single variable. @@ -2140,7 +2063,7 @@ the ``Generalizable`` vernacular command to avoid unexpected generalizations when mistyping identifiers. There are several commands that specify which variables should be generalizable. -.. cmd:: Generalizable All Variables. +.. cmd:: Generalizable All Variables All variables are candidate for generalization if they appear free in the context under a @@ -2148,16 +2071,16 @@ that specify which variables should be generalizable. of typos. In such cases, the context will probably contain some unexpected generalized variable. -.. cmd:: Generalizable No Variables. +.. cmd:: Generalizable No Variables Disable implicit generalization entirely. This is the default behavior. -.. cmd:: Generalizable (Variable | Variables) {+ @ident }. +.. cmd:: Generalizable (Variable | Variables) {+ @ident } Allow generalization of the given identifiers only. Calling this command multiple times adds to the allowed identifiers. -.. cmd:: Global Generalizable. +.. cmd:: Global Generalizable Allows exporting the choice of generalizable variables. @@ -2177,6 +2100,7 @@ implicitly, as maximally-inserted arguments. In these binders, the binding name for the bound object is optional, whereas the type is mandatory, dually to regular binders. +.. _Coercions: Coercions --------- @@ -2201,43 +2125,38 @@ to coercions are provided in :ref:`implicitcoercions`. Printing constructions in full ------------------------------ +.. opt:: Printing All + Coercions, implicit arguments, the type of pattern-matching, but also notations (see :ref:`syntaxextensionsandinterpretationscopes`) can obfuscate the behavior of some tactics (typically the tactics applying to occurrences of subterms are -sensitive to the implicit arguments). The command - -.. cmd:: Set Printing All. - +sensitive to the implicit arguments). Turning this option on deactivates all high-level printing features such as coercions, implicit arguments, returned type of pattern-matching, notations and various syntactic sugar for pattern-matching or record projections. -Otherwise said, ``Set Printing All`` includes the effects of the commands -``Set Printing Implicit``, ``Set Printing Coercions``, ``Set Printing Synth``, -``Unset Printing Projections``, and ``Unset Printing Notations``. To reactivate -the high-level printing features, use the command +Otherwise said, :opt:`Printing All` includes the effects of the options +:opt:`Printing Implicit`, :opt:`Printing Coercions`, :opt:`Printing Synth`, +:opt:`Printing Projections`, and :opt:`Printing Notations`. To reactivate +the high-level printing features, use the command ``Unset Printing All``. -.. cmd:: Unset Printing All. +.. _printing-universes: Printing universes ------------------ -The following command: - -.. cmd:: Set Printing Universes. - -activates the display of the actual level of each occurrence of ``Type``. -See :ref:`TODO-4.1.1-sorts` for details. This wizard option, in combination -with ``Set Printing All`` (see :ref:`printing_constructions_full`) can help to diagnose failures -to unify terms apparently identical but internally different in the -Calculus of Inductive Constructions. To reactivate the display of the -actual level of the occurrences of Type, use +.. opt:: Printing Universes -.. cmd:: Unset Printing Universes. +Turn this option on to activate the display of the actual level of each +occurrence of :g:`Type`. See :ref:`Sorts` for details. This wizard option, in +combination with :opt:`Printing All` can help to diagnose failures to unify +terms apparently identical but internally different in the Calculus of Inductive +Constructions. The constraints on the internal level of the occurrences of Type -(see :ref:`TODO-4.1.1-sorts`) can be printed using the command +(see :ref:`Sorts`) can be printed using the command -.. cmd:: Print {? Sorted} Universes. +.. cmd:: Print {? Sorted} Universes + :name: Print Universes If the optional ``Sorted`` option is given, each universe will be made equivalent to a numbered label reflecting its level (with a linear @@ -2245,12 +2164,13 @@ ordering) in the universe hierarchy. This command also accepts an optional output filename: -.. cmd:: Print {? Sorted} Universes @string. +.. cmdv:: Print {? Sorted} Universes @string If `string` ends in ``.dot`` or ``.gv``, the constraints are printed in the DOT language, and can be processed by Graphviz tools. The format is unspecified if `string` doesn’t end in ``.dot`` or ``.gv``. +.. _existential-variables: Existential variables --------------------- @@ -2260,9 +2180,9 @@ subterms to eventually be replaced by actual subterms. Existential variables are generated in place of unsolvable implicit arguments or “_” placeholders when using commands such as ``Check`` (see -Section :ref:`TODO-6.3.1-check`) or when using tactics such as ``refine`` (see Section -:ref:`TODO-8.2.3-refine`), as well as in place of unsolvable instances when using -tactics such that ``eapply`` (see Section :ref:`TODO-8.2.4-apply`). An existential +Section :ref:`requests-to-the-environment`) or when using tactics such as +:tacn:`refine`, as well as in place of unsolvable instances when using +tactics such that :tacn:`eapply`. An existential variable is defined in a context, which is the context of variables of the placeholder which generated the existential variable, and a type, which is the expected type of the placeholder. @@ -2307,25 +2227,20 @@ existential variable used in the same context as its context of definition is wr Existential variables can be named by the user upon creation using the syntax ``?``\ `ident`. This is useful when the existential variable needs to be explicitly handled later in the script (e.g. -with a named-goal selector, see :ref:`TODO-9.2-goal-selectors`). +with a named-goal selector, see :ref:`goal-selectors`). .. _explicit-display-existentials: Explicit displaying of existential instances for pretty-printing ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -The command: - -.. cmd:: Set Printing Existential Instances. - -activates the full display of how the context of an existential -variable is instantiated at each of the occurrences of the existential -variable. +.. opt:: Printing Existential Instances -To deactivate the full display of the instances of existential -variables, use +This option (off by default) activates the full display of how the +context of an existential variable is instantiated at each of the +occurrences of the existential variable. -.. cmd:: Unset Printing Existential Instances. +.. _tactics-in-terms: Solving existential variables using tactics ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -2338,7 +2253,7 @@ is not specified and is implementation-dependent. The inner tactic may use any variable defined in its scope, including repeated alternations between variables introduced by term binding as well as those introduced by tactic binding. The expression `tacexpr` can be any tactic -expression as described in :ref:`thetacticlanguage`. +expression as described in :ref:`ltac`. .. coqtop:: all @@ -2349,5 +2264,5 @@ using highly automated tactics without resorting to writing the proof-term by means of the interactive proof engine. This mechanism is comparable to the ``Declare Implicit Tactic`` command -defined at :ref:`TODO-8.9.7-implicit-automation`, except that the used +defined at :ref:`tactics-implicit-automation`, except that the used tactic is local to each hole instead of being declared globally. |