diff --git a/include/r3.h b/include/r3.h
index c68559b..b2562c9 100644
--- a/include/r3.h
+++ b/include/r3.h
@@ -180,44 +180,6 @@ enum { NODE_COMPARE_STR, NODE_COMPARE_PCRE, NODE_COMPARE_OPCODE };
 
 enum { OP_EXPECT_MORE_DIGITS = 1, OP_EXPECT_MORE_WORDS, OP_EXPECT_NOSLASH, OP_EXPECT_NODASH, OP_EXPECT_MORE_ALPHA };
 
-typedef struct {
-    /**
-     * source path
-     */
-    char * path;
-
-    int path_len;
-
-    /**
-     * slug start pointer
-     */
-    char * begin;
-
-    /**
-     * slug end pointer
-     */
-    char * end;
-
-    /**
-     * slug length
-     */
-    int len;
-
-    // slug pattern pointer if we have one
-    char * pattern;
-
-    // the length of custom pattern, if the pattern is found.
-    int    pattern_len;
-
-} r3_slug_t;
-
-
-r3_slug_t * r3_slug_parse(const char *needle, int needle_len, char **errstr);
-
-char * r3_slug_to_str(r3_slug_t *s);
-
-void r3_slug_free(r3_slug_t * s);
-
 #ifdef ENABLE_JSON
 json_object * r3_edge_to_json_object(const edge * e);
 json_object * r3_node_to_json_object(const node * n);
diff --git a/src/Makefile.am b/src/Makefile.am
index e154d2a..d43514d 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -3,7 +3,7 @@ AM_LDFLAGS=$(DEPS_LIBS) $(GVC_DEPS_LIBS) $(JSONC_LIBS)
 
 noinst_LTLIBRARIES = libr3core.la
 # lib_LIBRARIES = libr3.a
-libr3core_la_SOURCES = node.c edge.c str.c token.c match_entry.c
+libr3core_la_SOURCES = node.c edge.c str.c token.c match_entry.c slug.c
 
 if ENABLE_JSON
 libr3core_la_SOURCES += json.c
diff --git a/src/slug.c b/src/slug.c
new file mode 100644
index 0000000..1ed197c
--- /dev/null
+++ b/src/slug.c
@@ -0,0 +1,119 @@
+/*
+ * slug.c
+ * Copyright (C) 2014 c9s <c9s@c9smba.local>
+ *
+ * Distributed under terms of the MIT license.
+ */
+#include <stdlib.h>
+#include <string.h>
+#include "config.h"
+#include "r3.h"
+#include "r3_str.h"
+#include "slug.h"
+#include "zmalloc.h"
+
+r3_slug_t * r3_slug_new(char * path, int path_len) {
+    r3_slug_t * s = zmalloc(sizeof(r3_slug_t));
+    s->path = path;
+    s->path_len = path_len;
+
+    s->begin = NULL;
+    s->end = NULL;
+    s->len = 0;
+
+    s->pattern = NULL;
+    s->pattern_len = 0;
+    return s;
+}
+
+void r3_slug_free(r3_slug_t * s) {
+    zfree(s);
+}
+
+
+/**
+ * Return 1 means OK
+ * Return 0 means Empty
+ * Return -1 means Error
+ */
+int r3_slug_check(r3_slug_t *s, char **errstr) {
+    // if it's empty
+    if (s->begin == NULL && s->len == 0) {
+        return 0;
+    }
+    if (s->begin && s->begin == s->end && s->len == 0) {
+        return 0;
+    }
+
+    // if the head is defined, we should also have end pointer
+    if (s->begin && s->end == NULL) {
+        return -1;
+    }
+    return 0;
+}
+
+
+char * r3_slug_to_str(r3_slug_t *s) {
+    char *str = NULL;
+    asprintf(&str, "slug: '%.*s', pattern: '%.*s', path: '%.*s'", s->len, s->begin, s->pattern_len, s->pattern, s->path_len, s->path);
+    return str;
+}
+
+
+/*
+r3_slug_t * r3_slug_parse_next(r3_slug_t *s, char **errstr) {
+    return r3_slug_parse(s->end, s->path_len - (s->end - s->begin), errstr);
+}
+*/
+
+r3_slug_t * r3_slug_parse(const char *needle, int needle_len, char *offset, char **errstr) {
+    r3_slug_t * s = r3_slug_new(needle, needle_len);
+
+    int cnt = 0;
+    int state = 0;
+    char * p = offset;
+
+    while( (p-needle) < needle_len) {
+
+        if (*p == '\\' ) {
+            p++; p++;
+        }
+        if (state == 0 && *p == '{') {
+            s->begin = p+1; 
+        }
+
+        if (state == 1 && *p == ':') {
+            // start from next
+            s->pattern = p+1;
+        }
+
+        // closing slug
+        if (state == 1 && *p == '}') {
+            s->end = p;
+            s->len = s->end - s->begin;
+            if (s->pattern) {
+                s->pattern_len = p - s->pattern;
+            }
+
+            cnt++;
+            state--;
+            break;
+        }
+
+        if ( *p == '{' ) {
+            state++;
+        } else if ( *p == '}' ) {
+            state--;
+        }
+        p++;
+    };
+
+    if (state > 0) {
+        if (errstr) {
+            asprintf(errstr, "incomplete slug pattern. PATH (%d): '%s', OFFSET: %ld, STATE: %d", needle_len, needle, p - needle, state);
+        }
+        return NULL;
+    }
+
+    return s;
+}
diff --git a/src/slug.h b/src/slug.h
new file mode 100644
index 0000000..afde660
--- /dev/null
+++ b/src/slug.h
@@ -0,0 +1,52 @@
+/*
+ * slug.h
+ * Copyright (C) 2014 c9s <c9s@c9smba.local>
+ *
+ * Distributed under terms of the MIT license.
+ */
+#ifndef R3_SLUG_H
+#define R3_SLUG_H
+
+typedef struct {
+    /**
+     * source path
+     */
+    char * path;
+
+    int path_len;
+
+    /**
+     * slug start pointer
+     */
+    char * begin;
+
+    /**
+     * slug end pointer
+     */
+    char * end;
+
+    /**
+     * slug length
+     */
+    int len;
+
+    // slug pattern pointer if we have one
+    char * pattern;
+
+    // the length of custom pattern, if the pattern is found.
+    int    pattern_len;
+
+} r3_slug_t;
+
+
+r3_slug_t * r3_slug_new(char * path, int path_len);
+
+int r3_slug_check(r3_slug_t *s, char **errstr);
+
+r3_slug_t * r3_slug_parse(const char *needle, int needle_len, char *offset, char **errstr);
+
+char * r3_slug_to_str(r3_slug_t *s);
+
+void r3_slug_free(r3_slug_t * s);
+
+#endif /* !SLUG_H */
diff --git a/src/str.c b/src/str.c
index 3219f73..5e708c4 100644
--- a/src/str.c
+++ b/src/str.c
@@ -38,90 +38,6 @@ int r3_pattern_to_opcode(const char * pattern, int len) {
 }
 
 
-r3_slug_t * r3_slug_new(char * path, int path_len) {
-    r3_slug_t * s = zmalloc(sizeof(r3_slug_t));
-    s->path = path;
-    s->path_len = path_len;
-
-    s->begin = NULL;
-    s->end = NULL;
-    s->len = 0;
-
-    s->pattern = NULL;
-    s->pattern_len = 0;
-    return s;
-}
-
-void r3_slug_free(r3_slug_t * s) {
-    zfree(s);
-}
-
-int r3_slug_check(r3_slug_t *s, char **errstr) {
-    if (s->begin == NULL) {
-        return 1;
-    }
-    if (s->end == NULL) {
-        return 1;
-    }
-    return 0;
-}
-
-
-char * r3_slug_to_str(r3_slug_t *s) {
-    char *str = NULL;
-    asprintf(&str, "slug: '%.*s', pattern: '%.*s', path: '%.*s'", s->len, s->begin, s->pattern_len, s->pattern, s->path_len, s->path);
-    return str;
-}
-
-
-/*
-r3_slug_t * r3_slug_parse_next(r3_slug_t *s) {
-    r3_slug_parse(s->end, s->path_len - (s->end - s->begin), s->end;
-}
-*/
-
-
-r3_slug_t * r3_slug_parse(const char *needle, int needle_len, char **errstr) {
-    r3_slug_t * s = r3_slug_new(needle, needle_len);
-
-    int cnt = 0;
-    int state = 0;
-    char * p = (char*) needle;
-
-    while( (p-needle) < needle_len) {
-
-        if (*p == '\\' ) {
-            p++; p++;
-        }
-        if (state == 0 && *p == '{') {
-            s->begin = p+1; 
-        }
-
-        if (state == 1 && *p == ':') {
-            // start from next
-            s->pattern = p+1;
-        }
-
-        // closing slug
-        if (state == 1 && *p == '}') {
-            s->end = p;
-            s->len = s->end - s->begin;
-            if (s->pattern) {
-                s->pattern_len = p - s->pattern;
-            }
-            cnt++;
-            break;
-        }
-
-        if ( *p == '{' ) {
-            state++;
-        } else if ( *p == '}' ) {
-            state--;
-        }
-        p++;
-    };
-    return s;
-}
 
 /**
  * provide a quick way to count slugs, simply search for '{'
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 98334ed..fb15e51 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -6,8 +6,8 @@
 # endif
 TESTS =
 
-AM_CFLAGS=$(DEPS_CFLAGS) $(GVC_DEPS_CFLAGS) $(JSONC_CFLAGS) -I$(top_builddir) -I$(top_builddir)/include -I$(top_builddir)/3rdparty  -Wall -std=c99 -ggdb -Wall
-AM_LDFLAGS=$(DEPS_LIBS) $(GVC_DEPS_LIBS) $(JSONC_LIBS) -L$(top_builddir) -lr3 -lcheck @CHECK_LIBS@
+AM_CFLAGS=$(DEPS_CFLAGS) $(GVC_DEPS_CFLAGS) $(JSONC_CFLAGS) -I$(top_builddir) -I$(top_builddir)/include -I$(top_builddir)/src -I$(top_builddir)/3rdparty  -Wall -std=c99 -ggdb -Wall
+AM_LDFLAGS=$(DEPS_LIBS) $(GVC_DEPS_LIBS) $(JSONC_LIBS) -L$(top_builddir) -lcheck @CHECK_LIBS@ $(top_builddir)/libr3.la
 
 if USE_JEMALLOC
 AM_CFLAGS += -ljemalloc
diff --git a/tests/check_slug.c b/tests/check_slug.c
index e943b94..bae4d42 100644
--- a/tests/check_slug.c
+++ b/tests/check_slug.c
@@ -11,6 +11,7 @@
 #include "r3.h"
 #include "r3_str.h"
 #include "zmalloc.h"
+#include "slug.h"
 
 START_TEST (test_pattern_to_opcode)
 {
@@ -99,7 +100,7 @@ START_TEST (test_slug_parse_with_pattern)
 {
     char * pattern = "/user/{name:\\d{3}}";
     char * errstr = NULL;
-    r3_slug_t *s = r3_slug_parse(pattern, strlen(pattern), &errstr);
+    r3_slug_t *s = r3_slug_parse(pattern, strlen(pattern), pattern, &errstr);
 
     char * out = r3_slug_to_str(s);
     printf("%s\n",out);
@@ -114,7 +115,7 @@ START_TEST (test_slug_parse_without_pattern)
 {
     char * pattern = "/user/{name}";
     char * errstr = NULL;
-    r3_slug_t *s = r3_slug_parse(pattern, strlen(pattern), &errstr);
+    r3_slug_t *s = r3_slug_parse(pattern, strlen(pattern), pattern, &errstr);
 
     char * out = r3_slug_to_str(s);
     printf("%s\n",out);