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(*************************************************************)
(* This file is distributed under the terms of the *)
(* GNU Lesser General Public License Version 2.1 *)
(*************************************************************)
(* Benjamin.Gregoire@inria.fr Laurent.Thery@inria.fr *)
(*************************************************************)
(**********************************************************************
Tactic.v
Useful tactics
**********************************************************************)
(**************************************
A simple tactic to end a proof
**************************************)
Ltac finish := intros; auto; trivial; discriminate.
(**************************************
A tactic for proof by contradiction
with contradict H
H: ~A |- B gives |- A
H: ~A |- ~ B gives H: B |- A
H: A |- B gives |- ~ A
H: A |- B gives |- ~ A
H: A |- ~ B gives H: A |- ~ A
**************************************)
Ltac contradict name :=
let term := type of name in (
match term with
(~_) =>
match goal with
|- ~ _ => let x := fresh in
(intros x; case name;
generalize x; clear x name;
intro name)
| |- _ => case name; clear name
end
| _ =>
match goal with
|- ~ _ => let x := fresh in
(intros x; absurd term;
[idtac | exact name]; generalize x; clear x name;
intros name)
| |- _ => generalize name; absurd term;
[idtac | exact name]; clear name
end
end).
(**************************************
A tactic to do case analysis keeping the equality
**************************************)
Ltac case_eq name :=
generalize (refl_equal name); pattern name at -1 in |- *; case name.
(**************************************
A tactic to use f_equal? theorems
**************************************)
Ltac eq_tac :=
match goal with
|- (?g _ = ?g _) => apply f_equal with (f := g)
| |- (?g ?X _ = ?g ?X _) => apply f_equal with (f := g X)
| |- (?g _ _ = ?g _ _) => apply f_equal2 with (f := g)
| |- (?g ?X ?Y _ = ?g ?X ?Y _) => apply f_equal with (f := g X Y)
| |- (?g ?X _ _ = ?g ?X _ _) => apply f_equal2 with (f := g X)
| |- (?g _ _ _ = ?g _ _ _) => apply f_equal3 with (f := g)
| |- (?g ?X ?Y ?Z _ = ?g ?X ?Y ?Z _) => apply f_equal with (f := g X Y Z)
| |- (?g ?X ?Y _ _ = ?g ?X ?Y _ _) => apply f_equal2 with (f := g X Y)
| |- (?g ?X _ _ _ = ?g ?X _ _ _) => apply f_equal3 with (f := g X)
| |- (?g _ _ _ _ _ = ?g _ _ _ _) => apply f_equal4 with (f := g)
end.
(**************************************
A stupid tactic that tries auto also after applying sym_equal
**************************************)
Ltac sauto := (intros; apply sym_equal; auto; fail) || auto.
|
