diff --git a/Parser/parser.h b/Parser/parser.h
index ebb06c2..b16075e 100644
--- a/Parser/parser.h
+++ b/Parser/parser.h
@@ -11,7 +11,7 @@
 
 typedef struct {
     int              s_state;       /* State in current DFA */
-    dfa             *s_dfa;         /* Current DFA */
+    const dfa       *s_dfa;         /* Current DFA */
     struct _node    *s_parent;      /* Where to add next node */
 } stackentry;