# HG changeset patch
# User paulson
# Date 977235895 -3600
# Node ID 9285b4d87d7d7148115c5f0a242fa69f59b9adea
# Parent  f02834001fca3e9b78bb6412febe21cb230589cc
re-orienting equations with #nnn on the lhs

diff -r f02834001fca -r 9285b4d87d7d src/HOL/Numeral.ML
--- a/src/HOL/Numeral.ML	Tue Dec 19 15:20:23 2000 +0100
+++ b/src/HOL/Numeral.ML	Tue Dec 19 15:24:55 2000 +0100
@@ -8,3 +8,11 @@
 by(Simp_tac 1);
 qed "Let_number_of";
 Addsimps [Let_number_of];
+
+(*The condition "True" is a hack to prevent looping.
+  Conditional rewrite rules are tried after unconditional ones, so a rule
+  like eq_nat_number_of will be tried first to eliminate #mm=#nn. *)
+Goal "True ==> (number_of w = x) = (x = number_of w)";
+by Auto_tac;  
+qed "number_of_reorient";
+Addsimps [number_of_reorient];