--- code/trunk/testdata/testoutput1	2009/03/03 16:08:23	381
+++ code/trunk/testdata/testoutput1	2009/03/20 11:22:42	395
@@ -6641,4 +6641,9 @@
     abc
  0: ab
 
+/^%((?(?=[a])[^%])|b)*%$/
+    %ab%
+ 0: %ab%
+ 1: 
+
 / End of testinput1 /