diff --git a/include/types/acl.h b/include/types/acl.h
index 74db67b..0b6524b 100644
--- a/include/types/acl.h
+++ b/include/types/acl.h
@@ -93,6 +93,7 @@
 	const char *kw;
 	char *fetch_kw;
 	int (*parse)(const char *text, struct pattern *pattern, enum pat_usage usage, char **err);
+	int (*index)(struct pattern_expr *expr, struct pattern *pattern, char **err);
 	enum pat_match_res (*match)(struct sample *smp, struct pattern *pattern);
 	/* must be after the config params */
 	struct sample_fetch *smp; /* the sample fetch we depend on */