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authorThéo Zimmermann2020-04-20 18:11:51 +0200
committerThéo Zimmermann2020-04-20 18:11:51 +0200
commit34b5d2cf4383bd0cd89a1f896711dd4ac86decc0 (patch)
tree9df83607b4a6754fc883738de25ab8ad4738a0a5
parentacefe58cd39c9a4efee632f7f92f56fb4d5285bb (diff)
Remove Functional Scheme from Scheme chapter.
-rw-r--r--doc/sphinx/user-extensions/proof-schemes.rst141
1 files changed, 1 insertions, 140 deletions
diff --git a/doc/sphinx/user-extensions/proof-schemes.rst b/doc/sphinx/user-extensions/proof-schemes.rst
index 34197c4fcf..e05be7c2c2 100644
--- a/doc/sphinx/user-extensions/proof-schemes.rst
+++ b/doc/sphinx/user-extensions/proof-schemes.rst
@@ -190,146 +190,7 @@ Combined Scheme
Check tree_forest_mutrect.
-.. _functional-scheme:
-
-Generation of induction principles with ``Functional`` ``Scheme``
------------------------------------------------------------------
-
-
-.. cmd:: Functional Scheme @ident__0 := Induction for @ident' Sort @sort {* with @ident__i := Induction for @ident__i' Sort @sort}
-
- This command is a high-level experimental tool for
- generating automatically induction principles corresponding to
- (possibly mutually recursive) functions. First, it must be made
- available via ``Require Import FunInd``.
- Each :n:`@ident__i` is a different mutually defined function
- name (the names must be in the same order as when they were defined). This
- command generates the induction principle for each :n:`@ident__i`, following
- the recursive structure and case analyses of the corresponding function
- :n:`@ident__i'`.
-
-.. warning::
-
- There is a difference between induction schemes generated by the command
- :cmd:`Functional Scheme` and these generated by the :cmd:`Function`. Indeed,
- :cmd:`Function` generally produces smaller principles that are closer to how
- a user would implement them. See :ref:`advanced-recursive-functions` for details.
-
-.. example::
-
- Induction scheme for div2.
-
- We define the function div2 as follows:
-
- .. coqtop:: all
-
- Require Import FunInd.
- Require Import Arith.
-
- Fixpoint div2 (n:nat) : nat :=
- match n with
- | O => 0
- | S O => 0
- | S (S n') => S (div2 n')
- end.
-
- The definition of a principle of induction corresponding to the
- recursive structure of `div2` is defined by the command:
-
- .. coqtop:: all
-
- Functional Scheme div2_ind := Induction for div2 Sort Prop.
-
- You may now look at the type of div2_ind:
-
- .. coqtop:: all
-
- Check div2_ind.
-
- We can now prove the following lemma using this principle:
-
- .. coqtop:: all
-
- Lemma div2_le' : forall n:nat, div2 n <= n.
- intro n.
- pattern n, (div2 n).
- apply div2_ind; intros.
- auto with arith.
- auto with arith.
- simpl; auto with arith.
- Qed.
-
- We can use directly the functional induction (:tacn:`function induction`) tactic instead
- of the pattern/apply trick:
-
- .. coqtop:: all
-
- Reset div2_le'.
-
- Lemma div2_le : forall n:nat, div2 n <= n.
- intro n.
- functional induction (div2 n).
- auto with arith.
- auto with arith.
- auto with arith.
- Qed.
-
-.. example::
-
- Induction scheme for tree_size.
-
- We define trees by the following mutual inductive type:
-
- .. original LaTeX had "Variable" instead of "Axiom", which generates an ugly warning
-
- .. coqtop:: reset all
-
- Axiom A : Set.
-
- Inductive tree : Set :=
- node : A -> forest -> tree
- with forest : Set :=
- | empty : forest
- | cons : tree -> forest -> forest.
-
- We define the function tree_size that computes the size of a tree or a
- forest. Note that we use ``Function`` which generally produces better
- principles.
-
- .. coqtop:: all
-
- Require Import FunInd.
-
- Function tree_size (t:tree) : nat :=
- match t with
- | node A f => S (forest_size f)
- end
- with forest_size (f:forest) : nat :=
- match f with
- | empty => 0
- | cons t f' => (tree_size t + forest_size f')
- end.
-
- Notice that the induction principles ``tree_size_ind`` and ``forest_size_ind``
- generated by ``Function`` are not mutual.
-
- .. coqtop:: all
-
- Check tree_size_ind.
-
- Mutual induction principles following the recursive structure of ``tree_size``
- and ``forest_size`` can be generated by the following command:
-
- .. coqtop:: all
-
- Functional Scheme tree_size_ind2 := Induction for tree_size Sort Prop
- with forest_size_ind2 := Induction for forest_size Sort Prop.
-
- You may now look at the type of `tree_size_ind2`:
-
- .. coqtop:: all
-
- Check tree_size_ind2.
+.. seealso:: :ref:`functional-scheme`
.. _derive-inversion: