diff --git a/include/proto/pattern.h b/include/proto/pattern.h
index 80d4ee1..ee19392 100644
--- a/include/proto/pattern.h
+++ b/include/proto/pattern.h
@@ -68,7 +68,7 @@
 
 
 /* ignore the current line */
-int pat_parse_nothing(const char **text, struct pattern *pattern, int *opaque, char **err);
+int pat_parse_nothing(const char **text, struct pattern *pattern, enum pat_usage usage, int *opaque, char **err);
 
 /* NB: For two strings to be identical, it is required that their lengths match */
 enum pat_match_res pat_match_str(struct sample *smp, struct pattern *pattern);
@@ -83,37 +83,37 @@
 enum pat_match_res pat_match_int(struct sample *smp, struct pattern *pattern);
 
 /* Parse an integer. It is put both in min and max. */
-int pat_parse_int(const char **text, struct pattern *pattern, int *opaque, char **err);
+int pat_parse_int(const char **text, struct pattern *pattern, enum pat_usage usage, int *opaque, char **err);
 
 /* Parse len like an integer, but specify expected string type */
-int pat_parse_len(const char **text, struct pattern *pattern, int *opaque, char **err);
+int pat_parse_len(const char **text, struct pattern *pattern, enum pat_usage usage, int *opaque, char **err);
 
 /* Parse an version. It is put both in min and max. */
-int pat_parse_dotted_ver(const char **text, struct pattern *pattern, int *opaque, char **err);
+int pat_parse_dotted_ver(const char **text, struct pattern *pattern, enum pat_usage usage, int *opaque, char **err);
 
 /* Parse a range of integers delimited by either ':' or '-'. If only one
  * integer is read, it is set as both min and max.
  */
-int pat_parse_range(const char **text, struct pattern *pattern, int *opaque, char **err);
+int pat_parse_range(const char **text, struct pattern *pattern, enum pat_usage usage, int *opaque, char **err);
 
 /* Parse a string. It is allocated and duplicated. */
-int pat_parse_str(const char **text, struct pattern *pattern, int *opaque, char **err);
+int pat_parse_str(const char **text, struct pattern *pattern, enum pat_usage usage, int *opaque, char **err);
 
 /* Parse a hexa binary definition. It is allocated and duplicated. */
-int pat_parse_bin(const char **text, struct pattern *pattern, int *opaque, char **err);
+int pat_parse_bin(const char **text, struct pattern *pattern, enum pat_usage usage, int *opaque, char **err);
 
 /* Parse and concatenate strings into one. It is allocated and duplicated. */
-int pat_parse_strcat(const char **text, struct pattern *pattern, int *opaque, char **err);
+int pat_parse_strcat(const char **text, struct pattern *pattern, enum pat_usage usage, int *opaque, char **err);
 
 /* Parse a regex. It is allocated. */
-int pat_parse_reg(const char **text, struct pattern *pattern, int *opaque, char **err);
+int pat_parse_reg(const char **text, struct pattern *pattern, enum pat_usage usage, int *opaque, char **err);
 
 /* Parse an IP address and an optional mask in the form addr[/mask].
  * The addr may either be an IPv4 address or a hostname. The mask
  * may either be a dotted mask or a number of bits. Returns 1 if OK,
  * otherwise 0.
  */
-int pat_parse_ip(const char **text, struct pattern *pattern, int *opaque, char **err);
+int pat_parse_ip(const char **text, struct pattern *pattern, enum pat_usage usage, int *opaque, char **err);
 
 /* always return false */
 enum pat_match_res pat_match_nothing(struct sample *smp, struct pattern *pattern);
diff --git a/include/types/acl.h b/include/types/acl.h
index 9692015..afce939 100644
--- a/include/types/acl.h
+++ b/include/types/acl.h
@@ -92,7 +92,7 @@
 struct acl_keyword {
 	const char *kw;
 	char *fetch_kw;
-	int (*parse)(const char **text, struct pattern *pattern, int *opaque, char **err);
+	int (*parse)(const char **text, struct pattern *pattern, enum pat_usage usage, int *opaque, 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 */
diff --git a/include/types/pattern.h b/include/types/pattern.h
index 7065b6b..4e89372 100644
--- a/include/types/pattern.h
+++ b/include/types/pattern.h
@@ -61,6 +61,15 @@
 	PAT_MATCH = 3,           /* sample matched at least one pattern */
 };
 
+/* This enum describe the running mode of the function pat_parse_*().
+ * The lookup mode does not allocate memory. The compile mode allocate
+ * memory and create any data
+ */
+enum pat_usage {
+	PAT_U_LOOKUP,
+	PAT_U_COMPILE,
+};
+
 /* possible flags for expressions or patterns */
 enum {
 	PAT_F_IGNORE_CASE = 1 << 0,       /* ignore case */
@@ -151,14 +160,14 @@
  * are grouped together in order to optimize caching.
  */
 struct pattern_expr {
-	int (*parse)(const char **text, struct pattern *pattern, int *opaque, char **err);
+	int (*parse)(const char **text, struct pattern *pattern, enum pat_usage usage, int *opaque, char **err);
 	enum pat_match_res (*match)(struct sample *smp, struct pattern *pattern);
 	struct list patterns;         /* list of acl_patterns */
 	struct eb_root pattern_tree;  /* may be used for lookup in large datasets */
 };
 
 extern char *pat_match_names[PAT_MATCH_NUM];
-extern int (*pat_parse_fcts[PAT_MATCH_NUM])(const char **, struct pattern *, int *, char **);
+extern int (*pat_parse_fcts[PAT_MATCH_NUM])(const char **, struct pattern *, enum pat_usage, int *, char **);
 extern enum pat_match_res (*pat_match_fcts[PAT_MATCH_NUM])(struct sample *, struct pattern *);
 extern int pat_match_types[PAT_MATCH_NUM];