better autodestruct ?

1 files changed, 16 insertions, 1 deletions

diff --git a/lib/OptionMonad.v b/lib/OptionMonad.v
index d2563c97..18430e04 100644
--- a/lib/OptionMonad.v
+++ b/lib/OptionMonad.v
@@ -13,7 +13,22 @@ Local Open Scope option_monad_scope.
 
 (** Simple tactics for option-monad *)
 
-Ltac autodestruct := 
+Ltac deepest_match exp := 
+  match exp with
+  | context f [match ?expr with | _ => _ end] => ltac: (deepest_match expr)
+  | _ => exp
+  end.
+
+Ltac autodestruct :=
+  let EQ := fresh "EQ" in 
+  match goal with
+  | |- context f [match ?expr with | _ => _ end] => 
+    let t := ltac: (deepest_match expr) in
+    destruct t eqn:EQ; generalize EQ; clear EQ; congruence || trivial
+  end.
+
+(* deprecated version of "autodestruct". the new one seems a better replacement *)
+Ltac dummy_autodestruct := 
   let EQ := fresh "EQ" in 
   match goal with
   | |- context f [match ?expr with | _ => _ end] => destruct expr eqn:EQ; generalize EQ; clear EQ; congruence || trivial