--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/IOA/meta_theory/Option.ML	Wed Nov 02 11:50:09 1994 +0100
@@ -0,0 +1,8 @@
+val option_rws = Let_def :: Option.option.simps;
+val SS = arith_ss addsimps option_rws;
+
+val [prem] = goal Option.thy "P(opt) ==> P(None) | (? x. P(Some(x)))";
+ br (prem RS rev_mp) 1;
+ by (Option.option.induct_tac "opt" 1);
+ by (ALLGOALS(fast_tac HOL_cs));
+val optE = standard(result() RS disjE);