From 408e270aca41528348aad7e80323f75f1c82765d Mon Sep 17 00:00:00 2001 From: Jason Gross Date: Tue, 7 Nov 2017 18:41:37 -0500 Subject: Add HeadUnderBinders --- src/Util/Tactics/HeadUnderBinders.v | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) create mode 100644 src/Util/Tactics/HeadUnderBinders.v (limited to 'src/Util/Tactics') diff --git a/src/Util/Tactics/HeadUnderBinders.v b/src/Util/Tactics/HeadUnderBinders.v new file mode 100644 index 000000000..a111a045f --- /dev/null +++ b/src/Util/Tactics/HeadUnderBinders.v @@ -0,0 +1,22 @@ +Require Export Crypto.Util.FixCoqMistakes. + +(** find the head of the given expression, underneath [fun] and [forall] *) +Ltac head_under_binders_gen redtac expr := + let expr := redtac expr in + match expr with + | ?f _ => head_under_binders_gen redtac f + | fun x : ?T => @?f x + => lazymatch constr:(fun x : T + => ltac:(let f' := (eval cbv beta in (f x)) in + let h := head_under_binders_gen redtac f' in + exact h)) with + | fun _ => ?f => f + | ?f => f + end + | forall x, @?f x + => head_under_binders_gen redtac f + | ?expr => expr + end. + +Ltac head_under_binders expr := head_under_binders_gen ltac:(fun e => e) expr. +Ltac head_hnf_under_binders expr := head_under_binders_gen ltac:(fun e => eval hnf in e) expr. -- cgit v1.2.3