Add [normalize_commutative_identifier] tactic

1 files changed, 16 insertions, 0 deletions

diff --git a/src/Util/Tactics/RewriteWithCommutativity.v b/src/Util/Tactics/RewriteWithCommutativity.v
new file mode 100644
index 000000000..00af95566
--- /dev/null
+++ b/src/Util/Tactics/RewriteWithCommutativity.v
@@ -0,0 +1,16 @@
+(** Rewrite with the commutative property to ensure that all appearences of an identifier show up the same way *)
+
+Ltac rewrite_with_comm id clem x y :=
+  first [ constr_eq x y; fail 1
+        | repeat match goal with
+                 | [ H' : context[id y x] |- _ ]
+                   => rewrite clem in H'
+                 | [ |- context[id y x] ]
+                   => rewrite clem
+                 end ].
+
+Ltac normalize_commutative_identifier id id_comm :=
+  repeat match goal with
+         | [ |- context[id ?x ?y] ] => progress rewrite_with_comm id (id_comm y x) x y
+         | [ H : context[id ?x ?y] |- _ ] => progress rewrite_with_comm id (id_comm y x) x y
+         end.