diff --git a/lib/include/simulate.h b/lib/include/simulate.h
index 7b37470cf13b0a4cd87119a434600f268f107d91..404014dbbac8d09cd63d1ff291fc072d59e2ccf3 100644
--- a/lib/include/simulate.h
+++ b/lib/include/simulate.h
@@ -1,5 +1,5 @@
 #define list multiset
 #define perror(X) werror(X)
 #define efun predef
-#define regexp(X,Y) filter((X),regexp(Y)->match)
+#define regexp(X,Y) filter((X),Regexp(Y)->match)
 import Simulate;