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authorGravatar Théo Zimmermann <theo.zimmermann@univ-paris-diderot.fr>2018-04-26 13:11:25 +0200
committerGravatar Théo Zimmermann <theo.zimmermann@univ-paris-diderot.fr>2018-05-05 11:54:05 +0200
commit830a2e508ca951757dbe7923407f5d02442a4920 (patch)
treeadf7639a2d138b7eedb399b106b749746a692501 /doc/sphinx/proof-engine/tactics.rst
parentc0cbb8d3cc52ec0e3562d24038c45d8a756aa981 (diff)
[sphinx] Improvements around injection tactic.
Diffstat (limited to 'doc/sphinx/proof-engine/tactics.rst')
-rw-r--r--doc/sphinx/proof-engine/tactics.rst123
1 files changed, 63 insertions, 60 deletions
diff --git a/doc/sphinx/proof-engine/tactics.rst b/doc/sphinx/proof-engine/tactics.rst
index 459c8500d..3470098ec 100644
--- a/doc/sphinx/proof-engine/tactics.rst
+++ b/doc/sphinx/proof-engine/tactics.rst
@@ -1921,7 +1921,7 @@ See also: :ref:`advanced-recursive-functions`
:g:`t`:sub:`1` and :g:`t`:sub:`2` are equal too.
If :n:`@term` is a proof of a statement of conclusion :n:`@term = @term`,
- then ``injection`` applies the injectivity of constructors as deep as
+ then :tacn:`injection` applies the injectivity of constructors as deep as
possible to derive the equality of all the subterms of :n:`@term` and
:n:`@term` at positions where the terms start to differ. For example, from
:g:`(S p, S n) = (q, S (S m))` we may derive :g:`S p = q` and
@@ -1931,93 +1931,96 @@ See also: :ref:`advanced-recursive-functions`
equality of all the subterms at positions where they differ and adds them as
antecedents to the conclusion of the current goal.
-.. example::
+ .. example::
- Consider the following goal:
+ Consider the following goal:
- .. coqtop:: reset all
+ .. coqtop:: in
- Inductive list : Set :=
- | nil : list
- | cons : nat -> list -> list.
- Variable P : list -> Prop.
- Goal forall l n, P nil -> cons n l = cons 0 nil -> P l.
- intros.
- injection H0.
+ Inductive list : Set :=
+ | nil : list
+ | cons : nat -> list -> list.
+ Parameter P : list -> Prop.
+ Goal forall l n, P nil -> cons n l = cons 0 nil -> P l.
+ .. coqtop:: all
-Beware that injection yields an equality in a sigma type whenever the
-injected object has a dependent type :g:`P` with its two instances in
-different types :g:`(P t`:sub:`1` :g:`... t`:sub:`n` :g:`)` and
-:g:`(P u`:sub:`1` :g:`... u`:sub:`n` :sub:`)`. If :g:`t`:sub:`1` and
-:g:`u`:sub:`1` are the same and have for type an inductive type for which a decidable
-equality has been declared using the command ``Scheme Equality`` (see :ref:`proofschemes-induction-principles`),
-the use of a sigma type is avoided.
+ intros.
+ injection H0.
-.. note::
- If some quantified hypothesis of the goal is named :n:`@ident`,
- then :n:`injection @ident` first introduces the hypothesis in the local
- context using :n:`intros until @ident`.
+ Beware that injection yields an equality in a sigma type whenever the
+ injected object has a dependent type :g:`P` with its two instances in
+ different types :g:`(P t`:sub:`1` :g:`... t`:sub:`n` :g:`)` and
+ :g:`(P u`:sub:`1` :g:`... u`:sub:`n` :sub:`)`. If :g:`t`:sub:`1` and
+ :g:`u`:sub:`1` are the same and have for type an inductive type for which a decidable
+ equality has been declared using the command :cmd:`Scheme Equality`
+ (see :ref:`proofschemes-induction-principles`),
+ the use of a sigma type is avoided.
-.. exn:: Not a projectable equality but a discriminable one.
-.. exn:: Nothing to do, it is an equality between convertible @terms.
-.. exn:: Not a primitive equality.
-.. exn:: Nothing to inject.
+ .. note::
+ If some quantified hypothesis of the goal is named :n:`@ident`,
+ then :n:`injection @ident` first introduces the hypothesis in the local
+ context using :n:`intros until @ident`.
-.. tacv:: injection @num
+ .. exn:: Not a projectable equality but a discriminable one.
+ .. exn:: Nothing to do, it is an equality between convertible @terms.
+ .. exn:: Not a primitive equality.
+ .. exn:: Nothing to inject.
- This does the same thing as :n:`intros until @num` followed by
- :n:`injection @ident` where :n:`@ident` is the identifier for the last
- introduced hypothesis.
+ .. tacv:: injection @num
-.. tacv:: injection @term with @bindings_list
+ This does the same thing as :n:`intros until @num` followed by
+ :n:`injection @ident` where :n:`@ident` is the identifier for the last
+ introduced hypothesis.
- This does the same as :n:`injection @term` but using the given bindings to
- instantiate parameters or hypotheses of :n:`@term`.
+ .. tacv:: injection @term with @bindings_list
-.. tacv:: einjection @num
-.. tacv:: einjection @term {? with @bindings_list}
- :name: einjection
+ This does the same as :n:`injection @term` but using the given bindings to
+ instantiate parameters or hypotheses of :n:`@term`.
- This works the same as :n:`injection` but if the type of :n:`@term`, or the
- type of the hypothesis referred to by :n:`@num`, has uninstantiated
- parameters, these parameters are left as existential variables.
+ .. tacv:: einjection @num
+ :name: einjection
+ .. tacv:: einjection @term {? with @bindings_list}
+
+ This works the same as :n:`injection` but if the type of :n:`@term`, or the
+ type of the hypothesis referred to by :n:`@num`, has uninstantiated
+ parameters, these parameters are left as existential variables.
-.. tacv:: injection
+ .. tacv:: injection
- If the current goal is of the form :n:`@term <> @term` , this behaves as
- :n:`intro @ident; injection @ident`.
+ If the current goal is of the form :n:`@term <> @term` , this behaves as
+ :n:`intro @ident; injection @ident`.
- .. exn:: goal does not satisfy the expected preconditions.
+ .. exn:: goal does not satisfy the expected preconditions.
-.. tacv:: injection @term {? with @bindings_list} as {+ @intro_pattern}
-.. tacv:: injection @num as {+ intro_pattern}
-.. tacv:: injection as {+ intro_pattern}
-.. tacv:: einjection @term {? with @bindings_list} as {+ intro_pattern}
-.. tacv:: einjection @num as {+ intro_pattern}
-.. tacv:: einjection as {+ intro_pattern}
+ .. tacv:: injection @term {? with @bindings_list} as {+ @intro_pattern}
+ .. tacv:: injection @num as {+ intro_pattern}
+ .. tacv:: injection as {+ intro_pattern}
+ .. tacv:: einjection @term {? with @bindings_list} as {+ intro_pattern}
+ .. tacv:: einjection @num as {+ intro_pattern}
+ .. tacv:: einjection as {+ intro_pattern}
These variants apply :n:`intros {+ @intro_pattern}` after the call to
- ``injection`` or ``einjection`` so that all equalities generated are moved in
+ :tacn:`injection` or :tacn:`einjection` so that all equalities generated are moved in
the context of hypotheses. The number of :n:`@intro_pattern` must not exceed
the number of equalities newly generated. If it is smaller, fresh
names are automatically generated to adjust the list of :n:`@intro_pattern`
to the number of new equalities. The original equality is erased if it
corresponds to an hypothesis.
-.. opt:: Structural Injection
+ .. opt:: Structural Injection
- This option ensure that :n:`injection @term` erases the original hypothesis
- and leaves the generated equalities in the context rather than putting them
- as antecedents of the current goal, as if giving :n:`injection @term as`
- (with an empty list of names). This option is off by default.
+ This option ensure that :n:`injection @term` erases the original hypothesis
+ and leaves the generated equalities in the context rather than putting them
+ as antecedents of the current goal, as if giving :n:`injection @term as`
+ (with an empty list of names). This option is off by default.
-.. opt:: Keep Proof Equalities
+ .. opt:: Keep Proof Equalities
- By default, :tacn:`injection` only creates new equalities between :n:`@terms`
- whose type is in sort :g:`Type` or :g:`Set`, thus implementing a special
- behavior for objects that are proofs of a statement in :g:`Prop`. This option
- controls this behavior.
+ By default, :tacn:`injection` only creates new equalities between :n:`@terms`
+ whose type is in sort :g:`Type` or :g:`Set`, thus implementing a special
+ behavior for objects that are proofs of a statement in :g:`Prop`. This option
+ controls this behavior.
.. tacn:: inversion @ident
:name: inversion