Lvc.Infra.AutoIndTac
Ltac revert_except E :=
repeat match goal with
[H : _ |- _] ⇒
match H with
| E ⇒ fail 1
| _ ⇒ revert H
end
end.
Ltac clear_except E :=
repeat match goal with
[H : _ |- _] ⇒
match H with
| E ⇒ fail
| _ ⇒ clear H
end
end.
Ltac clear_all :=
repeat match goal with
[H : _ |- _] ⇒ clear H
end.
Ltac revert_all :=
repeat match goal with
[H : _ |- _] ⇒ revert H
end.
Ltac remember_arguments E :=
let tac x := (try (is_var x; fail 1); remember (x)) in
repeat (match type of E with
| ?t ?x _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ⇒ tac x
| ?t ?x _ _ _ _ _ _ _ _ _ _ _ _ _ _ ⇒ tac x
| ?t ?x _ _ _ _ _ _ _ _ _ _ _ _ _ ⇒ tac x
| ?t ?x _ _ _ _ _ _ _ _ _ _ _ _ ⇒ tac x
| ?t ?x _ _ _ _ _ _ _ _ _ _ _ ⇒ tac x
| ?t ?x _ _ _ _ _ _ _ _ _ _ ⇒ tac x
| ?t ?x _ _ _ _ _ _ _ _ _ ⇒ tac x
| ?t ?x _ _ _ _ _ _ _ _ ⇒ tac x
| ?t ?x _ _ _ _ _ _ _ ⇒ tac x
| ?t ?x _ _ _ _ _ _ ⇒ tac x
| ?t ?x _ _ _ _ _ ⇒ tac x
| ?t ?x _ _ _ _ ⇒ tac x
| ?t ?x _ _ _ ⇒ tac x
| ?t ?x _ _ ⇒ tac x
| ?t ?x _ ⇒ tac x
| ?t ?x ⇒ tac x
end).
Ltac clear_dup :=
match goal with
| [ H : ?X |- _ ] ⇒
match goal with
| [ H´ : ?Y |- _ ] ⇒
match H with
| H´ ⇒ fail 2
| _ ⇒ unify X Y ; (clear H´ || clear H)
end
end
end.
Ltac inv_eqs :=
repeat (match goal with
| [ H : @eq _ ?x ?x |- _ ] ⇒ fail
| [ H : @eq _ ?x ?y |- _ ] ⇒ progress (inversion H; subst; try clear_dup)
end).
Ltac clear_trivial_eqs :=
repeat (progress (match goal with
| [ H : @eq _ ?x ?x |- _ ] ⇒ clear H
end)).
Tactic Notation "general" "induction" hyp(H) :=
remember_arguments H; revert_except H;
induction H; intros; (try inv_eqs); (try clear_trivial_eqs).
Module Test.
Require Import List.
Inductive decreasing : list nat → Prop :=
| base : decreasing nil
| step m n L : decreasing (n::L) → n ≤ m → decreasing (m :: n :: L).
Lemma all_zero_by_hand L
: decreasing (0::L) → ∀ x, In x L → x = 0.
Lemma all_zero L
: decreasing (0::L) → ∀ x, In x L → x = 0.
End Test.