diff options
Diffstat (limited to 'src/Util/Tactics')
-rw-r--r-- | src/Util/Tactics/HeadUnderBinders.v | 22 |
1 files changed, 22 insertions, 0 deletions
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. |