--- a/ProgTutorial/Recipes/Timing.thy	Fri Mar 01 00:49:15 2013 +0000
+++ b/ProgTutorial/Recipes/Timing.thy	Fri Apr 19 11:09:18 2013 +0100
@@ -52,7 +52,7 @@
 
 lemma "ackermann (3, 4) = 125"
 apply(tactic {* 
-  timing_wrapper (simp_tac (@{simpset} addsimps @{thms "eval_nat_numeral"}) 1) *})
+  timing_wrapper (simp_tac (@{context} addsimps @{thms "eval_nat_numeral"}) 1) *})
 done
 
 text {*