diff --git a/Makefile b/Makefile
index 76b3cfed..df65832d 100644
--- a/Makefile
+++ b/Makefile
@@ -3,7 +3,7 @@
 
 include config.mk
 
-SRC = client.c draw.c event.c layout.c awesome.c tag.c util.c config.c screen.c statusbar.c uicb.c window.c awesome-client-common.c
+SRC = client.c draw.c event.c layout.c awesome.c tag.c util.c config.c screen.c statusbar.c uicb.c window.c rules.c awesome-client-common.c
 OBJ = ${SRC:.c=.o} ${LAYOUTS:.c=.o}
 
 SRCCLIENT = awesome-client.c awesome-client-common.c util.c
diff --git a/client.c b/client.c
index c9757161..d772a891 100644
--- a/client.c
+++ b/client.c
@@ -27,6 +27,7 @@
 #include "awesome.h"
 #include "layout.h"
 #include "tag.h"
+#include "rules.h"
 #include "util.h"
 #include "statusbar.h"
 #include "window.h"
diff --git a/config.c b/config.c
index 9a85591c..bd18188c 100644
--- a/config.c
+++ b/config.c
@@ -32,6 +32,7 @@
 #include "draw.h"
 #include "event.h"
 #include "tag.h"
+#include "rules.h"
 #include "statusbar.h"
 #include "event.h"
 #include "layout.h"
diff --git a/rules.c b/rules.c
new file mode 100644
index 00000000..42c20bb1
--- /dev/null
+++ b/rules.c
@@ -0,0 +1,78 @@
+/*
+ * rules.c - rules management
+ *
+ * Copyright © 2007 Julien Danjou <julien@danjou.info>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+
+#include "util.h"
+#include "rules.h"
+
+Bool
+client_match_rule(Client *c, Rule *r)
+{
+    char *prop;
+    regmatch_t tmp;
+    ssize_t len;
+    XClassHint ch = { 0, 0 };
+    Bool ret;
+
+    XGetClassHint(c->display, c->win, &ch);
+
+    len = a_strlen(ch.res_class) + a_strlen(ch.res_name) + a_strlen(c->name);
+    prop = p_new(char, len + 3);
+
+    /* rule matching */
+    snprintf(prop, len + 3, "%s:%s:%s",
+             ch.res_class ? ch.res_class : "", ch.res_name ? ch.res_name : "", c->name);
+
+    ret = (r->propregex && !regexec(r->propregex, prop, 1, &tmp, 0));
+
+    p_delete(&prop);
+
+    if(ch.res_class)
+        XFree(ch.res_class);
+    if(ch.res_name)
+        XFree(ch.res_name);
+
+    return ret;
+}
+
+int
+get_client_screen_from_rules(Client *c, Rule *rules)
+{
+    Rule *r;
+
+    for(r = rules; r; r = r->next)
+        if(client_match_rule(c, r))
+            return r->screen;
+
+    return RULE_NOSCREEN;
+}
+
+Bool
+is_client_tag_from_rules(Client *c, Tag *t, Rule *r)
+{
+    regmatch_t tmp;
+
+    if(!regexec(r->tagregex, t->name, 1, &tmp, 0))
+        return True;
+
+    return False;
+}
+
+// vim: filetype=c:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99
diff --git a/rules.h b/rules.h
new file mode 100644
index 00000000..116acb49
--- /dev/null
+++ b/rules.h
@@ -0,0 +1,34 @@
+/*
+ * rules.h - rules management header
+ *
+ * Copyright © 2007 Julien Danjou <julien@danjou.info>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+
+#ifndef AWESOME_RULES_H
+#define AWESOME_RULES_H
+
+#include "config.h"
+
+#define RULE_NOSCREEN        -1
+
+Bool client_match_rule(Client *, Rule *);
+int get_client_screen_from_rules(Client *, Rule *);
+Bool is_client_tag_from_rules(Client *, Tag *, Rule *);
+
+#endif
+// vim: filetype=c:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99
diff --git a/tag.c b/tag.c
index 43f9f257..d5618fc5 100644
--- a/tag.c
+++ b/tag.c
@@ -26,6 +26,7 @@
 #include "layout.h"
 #include "tag.h"
 #include "util.h"
+#include "rules.h"
 
 int
 applyrules(Client *c, awesome_config *awesomeconf)
diff --git a/tag.h b/tag.h
index 0c410304..2ae039fb 100644
--- a/tag.h
+++ b/tag.h
@@ -24,8 +24,6 @@
 
 #include "client.h"
 
-#define RULE_NOSCREEN                                     -1
-
 /** Check if a client is tiled */
 #define IS_TILED(client, screen, tags, ntags)            (client && !client->isfloating && isvisible(client, screen, tags, ntags))