diff --git a/button.c b/button.c
index 8ee117f7..54e7d0da 100644
--- a/button.c
+++ b/button.c
@@ -91,7 +91,7 @@ luaA_button_array_set(lua_State *L, int oidx, int idx, button_array_t *buttons)
 
     lua_pushnil(L);
     while(lua_next(L, idx))
-        if(luaA_toudata(L, -1, "button"))
+        if(luaA_toudata(L, -1, &button_class))
             button_array_append(buttons, luaA_object_ref_item(L, oidx, -1));
         else
             lua_pop(L, 1);
diff --git a/button.h b/button.h
index 246def30..72730c2b 100644
--- a/button.h
+++ b/button.h
@@ -35,7 +35,7 @@ struct button_t
 };
 
 lua_class_t button_class;
-LUA_OBJECT_FUNCS(button_class, button_t, button, "button")
+LUA_OBJECT_FUNCS(button_class, button_t, button)
 ARRAY_FUNCS(button_t *, button, DO_NOTHING)
 
 int luaA_button_array_get(lua_State *, int, button_array_t *);
diff --git a/client.c b/client.c
index e19a1c98..f4422599 100644
--- a/client.c
+++ b/client.c
@@ -35,7 +35,7 @@
 client_t *
 luaA_client_checkudata(lua_State *L, int ud)
 {
-    client_t *c = luaL_checkudata(L, ud, "client");
+    client_t *c = luaA_checkudata(L, ud, &client_class);
     if(c->invalid)
         luaL_error(L, "client is invalid\n");
     return c;
@@ -48,7 +48,7 @@ luaA_client_checkudata(lua_State *L, int ud)
 static int
 luaA_client_gc(lua_State *L)
 {
-    client_t *c = luaL_checkudata(L, 1, "client");
+    client_t *c = luaA_checkudata(L, 1, &client_class);
     button_array_wipe(&c->buttons);
     key_array_wipe(&c->keys);
     xcb_get_wm_protocols_reply_wipe(&c->protocols);
diff --git a/client.h b/client.h
index cc85a297..cfa8d134 100644
--- a/client.h
+++ b/client.h
@@ -167,7 +167,7 @@ ARRAY_FUNCS(client_t *, client, DO_NOTHING)
 /** Client class */
 lua_class_t client_class;
 
-LUA_OBJECT_FUNCS(client_class, client_t, client, "client")
+LUA_OBJECT_FUNCS(client_class, client_t, client)
 
 #define client_need_reban(c) \
     do { \
diff --git a/common/luaclass.c b/common/luaclass.c
index e2f4bf32..654f85a7 100644
--- a/common/luaclass.c
+++ b/common/luaclass.c
@@ -34,34 +34,61 @@ struct lua_class_property
     lua_class_propfunc_t newindex;
 };
 
-typedef struct
+DO_ARRAY(lua_class_t *, lua_class, DO_NOTHING)
+
+static lua_class_array_t luaA_classes;
+
+/** Convert a object to a udata if possible.
+ * \param L The Lua VM state.
+ * \param ud The index.
+ * \param class The wanted class.
+ * \return A pointer to the object, NULL otherwise.
+ */
+void *
+luaA_toudata(lua_State *L, int ud, lua_class_t *class)
 {
-    int id;
-    lua_class_t *class;
-} lua_class_id_t;
+    void *p = lua_touserdata(L, ud);
+    if(p) /* value is a userdata? */
+        if(lua_getmetatable(L, ud)) /* does it have a metatable? */
+        {
+            lua_pushlightuserdata(L, class);
+            lua_rawget(L, LUA_REGISTRYINDEX);
+            if(!lua_rawequal(L, -1, -2)) /* does it have the correct mt? */
+                p = NULL;
+            lua_pop(L, 2); /* remove both metatables */
+        }
+    return p;
+}
 
-DO_ARRAY(lua_class_id_t, lua_class_id, DO_NOTHING)
+/** Check for a udata class.
+ * \param L The Lua VM state.
+ * \param ud The object index on the stack.
+ * \param class The wanted class.
+ */
+void *
+luaA_checkudata(lua_State *L, int ud, lua_class_t *class)
+{
+    void *p = luaA_toudata(L, ud, class);
+    if(!p)
+        luaL_typerror(L, ud, class->name);
+    return p;
+}
 
-static lua_class_id_array_t luaA_classes;
-
-/* This has to be initialized to the highest natural type of Lua */
-#define LUA_HIGHEST_TYPE LUA_TTHREAD
-
-/** Enhanced version of lua_type that recognizes setup Lua classes.
+/** Get an object lua_class.
  * \param L The Lua VM state.
  * \param idx The index of the object on the stack.
  */
-int
-luaA_type(lua_State *L, int idx)
+lua_class_t *
+luaA_class_get(lua_State *L, int idx)
 {
     int type = lua_type(L, idx);
 
     if(type == LUA_TUSERDATA)
         foreach(class, luaA_classes)
-            if(luaA_toudata(L, idx, class->class->name))
-                return class->id;
+            if(luaA_toudata(L, idx, *class))
+                return *class;
 
-    return type;
+    return NULL;
 }
 
 /** Enhanced version of lua_typename that recognizes setup Lua classes.
@@ -71,12 +98,14 @@ luaA_type(lua_State *L, int idx)
 const char *
 luaA_typename(lua_State *L, int idx)
 {
-    int type = luaA_type(L, idx);
+    int type = lua_type(L, idx);
 
-    if(type > LUA_HIGHEST_TYPE)
-        foreach(class, luaA_classes)
-            if(class->id == type)
-                return class->class->name;
+    if(type == LUA_TUSERDATA)
+    {
+        lua_class_t *lua_class = luaA_class_get(L, idx);
+        if(lua_class)
+            return lua_class->name;
+    }
 
     return lua_typename(L, type);
 }
@@ -129,18 +158,27 @@ luaA_class_setup(lua_State *L, lua_class_t *class,
                  const struct luaL_reg methods[],
                  const struct luaL_reg meta[])
 {
-    static int class_type_counter = LUA_HIGHEST_TYPE;
+    /* Create the metatable */
+    lua_newtable(L);
+    /* Register it with class pointer as key in the registry */
+    lua_pushlightuserdata(L, class);
+    /* Duplicate the metatable */
+    lua_pushvalue(L, -2);
+    lua_rawset(L, LUA_REGISTRYINDEX);
 
-    luaA_openlib(L, name, methods, meta);
+    lua_pushvalue(L, -1);           /* dup metatable                      2 */
+    lua_setfield(L, -2, "__index"); /* metatable.__index = metatable      1 */
+
+    luaL_register(L, NULL, meta);                                      /* 1 */
+    luaL_register(L, name, methods);                                   /* 2 */
+    lua_pushvalue(L, -1);           /* dup self as metatable              3 */
+    lua_setmetatable(L, -2);        /* set self as metatable              2 */
+    lua_pop(L, 2);
 
     class->allocator = allocator;
     class->name = name;
 
-    lua_class_id_array_append(&luaA_classes, (lua_class_id_t)
-                              {
-                                  .id = ++class_type_counter,
-                                  .class = class,
-                              });
+    lua_class_array_append(&luaA_classes, class);
 }
 
 void
@@ -214,29 +252,6 @@ lua_class_property_array_getbyid(lua_class_property_array_t *arr,
     return lua_class_property_array_lookup(arr, &lookup_prop);
 }
 
-/** Get the class of an object.
- * \param L The Lua VM state.
- * \param idx The index of the object on the stack.
- * \return The class if found, NULL otherwise.
- */
-static lua_class_t *
-luaA_class_get(lua_State *L, int idx)
-{
-    int type = luaA_type(L, 1);
-
-    /* Find the class. */
-    lua_class_t *class = NULL;
-
-    foreach(classid, luaA_classes)
-        if(classid->id == type)
-        {
-            class = classid->class;
-            break;
-        }
-
-    return class;
-}
-
 /** Get a property of a object.
  * \param L The Lua VM state.
  * \param lua_class The Lua class.
@@ -271,7 +286,7 @@ luaA_class_index(lua_State *L)
 
     /* Property does exist and has an index callback */
     if(prop && prop->index)
-        return prop->index(L, luaL_checkudata(L, 1, class->name));
+        return prop->index(L, luaA_checkudata(L, 1, class));
 
     return 0;
 }
@@ -293,7 +308,7 @@ luaA_class_newindex(lua_State *L)
 
     /* Property does exist and has a newindex callback */
     if(prop && prop->newindex)
-        return prop->newindex(L, luaL_checkudata(L, 1, class->name));
+        return prop->newindex(L, luaA_checkudata(L, 1, class));
 
     return 0;
 }
diff --git a/common/luaclass.h b/common/luaclass.h
index 2d0325ab..0d17faba 100644
--- a/common/luaclass.h
+++ b/common/luaclass.h
@@ -55,8 +55,8 @@ typedef struct
 
 typedef int (*lua_class_propfunc_t)(lua_State *, lua_object_t *);
 
-int luaA_type(lua_State *, int);
 const char * luaA_typename(lua_State *, int);
+lua_class_t * luaA_class_get(lua_State *, int);
 
 void luaA_class_add_signal(lua_State *, lua_class_t *, const char *, int);
 void luaA_class_remove_signal(lua_State *, lua_class_t *, const char *, int);
@@ -74,6 +74,9 @@ int luaA_class_index(lua_State *);
 int luaA_class_newindex(lua_State *);
 int luaA_class_new(lua_State *, lua_class_t *);
 
+void * luaA_checkudata(lua_State *, int, lua_class_t *);
+void * luaA_toudata(lua_State *L, int ud, lua_class_t *);
+
 #define LUA_CLASS_FUNCS(prefix, lua_class) \
     static inline int                                                          \
     luaA_##prefix##_class_add_signal(lua_State *L)                             \
diff --git a/common/lualib.h b/common/lualib.h
index c611b90c..dce2d5d3 100644
--- a/common/lualib.h
+++ b/common/lualib.h
@@ -120,27 +120,6 @@ luaA_dofunction(lua_State *L, int nargs, int nret)
     return true;
 }
 
-/** Convert a object to a udata if possible.
- * \param L The Lua VM state.
- * \param ud The index.
- * \param tname The type name.
- * \return A pointer to the object, NULL otherwise.
- */
-static inline void *
-luaA_toudata(lua_State *L, int ud, const char *tname)
-{
-    void *p = lua_touserdata(L, ud);
-    if(p) /* value is a userdata? */
-        if(lua_getmetatable(L, ud)) /* does it have a metatable? */
-        {
-            lua_getfield(L, LUA_REGISTRYINDEX, tname); /* get correct metatable */
-            if(!lua_rawequal(L, -1, -2)) /* does it have the correct mt? */
-                p = NULL;
-            lua_pop(L, 2); /* remove both metatables */
-        }
-    return p;
-}
-
 #define luaA_checktable(L, n) \
     do { \
         if(!lua_istable(L, n)) \
diff --git a/common/luaobject.c b/common/luaobject.c
index 03c6f1eb..72fe303f 100644
--- a/common/luaobject.c
+++ b/common/luaobject.c
@@ -139,6 +139,15 @@ luaA_object_decref(lua_State *L, int tud, void *pointer)
     }
 }
 
+int
+luaA_settype(lua_State *L, lua_class_t *lua_class)
+{
+    lua_pushlightuserdata(L, lua_class);
+    lua_rawget(L, LUA_REGISTRYINDEX);
+    lua_setmetatable(L, -2);
+    return 1;
+}
+
 /** Add a signal to an object.
  * \param L The Lua VM state.
  * \param oud The object index on the stack.
@@ -219,4 +228,24 @@ luaA_object_emit_signal_simple(lua_State *L)
     return 0;
 }
 
+int
+luaA_object_tostring(lua_State *L)
+{
+    lua_class_t *lua_class = luaA_class_get(L, 1);
+    lua_pushfstring(L, "%s: %p", lua_class->name, luaA_checkudata(L, 1, lua_class));
+    return 1;
+}
+
+/** Garbage collect a Lua object.
+ * \param L The Lua VM state.
+ * \return The number of elements pushed on stack.
+ */
+int
+luaA_object_gc(lua_State *L)
+{
+    lua_object_t *item = lua_touserdata(L, 1);
+    signal_array_wipe(&item->signals);
+    return 0;
+}
+
 // vim: filetype=c:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=80
diff --git a/common/luaobject.h b/common/luaobject.h
index af75d1af..e338fdad 100644
--- a/common/luaobject.h
+++ b/common/luaobject.h
@@ -24,16 +24,9 @@
 
 #include "common/luaclass.h"
 
-static inline int
-luaA_settype(lua_State *L, const char *type)
-{
-    luaL_getmetatable(L, type);
-    lua_setmetatable(L, -2);
-    return 1;
-}
-
 #define LUAA_OBJECT_REGISTRY_KEY "awesome.object.registry"
 
+int luaA_settype(lua_State *, lua_class_t *);
 void luaA_object_setup(lua_State *);
 void * luaA_object_incref(lua_State *, int, int);
 void luaA_object_decref(lua_State *, int, void *);
@@ -149,14 +142,14 @@ int luaA_object_add_signal_simple(lua_State *);
 int luaA_object_remove_signal_simple(lua_State *);
 int luaA_object_emit_signal_simple(lua_State *);
 
-#define LUA_OBJECT_FUNCS(lua_class, type, prefix, lua_type)                    \
+#define LUA_OBJECT_FUNCS(lua_class, type, prefix)                              \
     LUA_CLASS_FUNCS(prefix, lua_class)                                         \
     static inline type *                                                       \
     prefix##_new(lua_State *L)                                                 \
     {                                                                          \
         type *p = lua_newuserdata(L, sizeof(type));                            \
         p_clear(p, 1);                                                         \
-        luaA_settype(L, lua_type);                                             \
+        luaA_settype(L, &(lua_class));                                         \
         lua_newtable(L);                                                       \
         lua_newtable(L);                                                       \
         lua_setmetatable(L, -2);                                               \
@@ -164,13 +157,6 @@ int luaA_object_emit_signal_simple(lua_State *);
         lua_pushvalue(L, -1);                                                  \
         luaA_class_emit_signal(L, &(lua_class), "new", 1);                     \
         return p;                                                              \
-    }                                                                          \
-                                                                               \
-    static inline int                                                          \
-    luaA_##prefix##_tostring(lua_State *L)                                     \
-    {                                                                          \
-        lua_pushfstring(L, lua_type ": %p", luaL_checkudata(L, 1, lua_type));  \
-        return 1;                                                              \
     }
 
 #define LUA_OBJECT_EXPORT_PROPERTY(pfx, type, field, pusher) \
@@ -181,20 +167,11 @@ int luaA_object_emit_signal_simple(lua_State *);
         return 1; \
     }
 
-/** Garbage collect a Lua object.
- * \param L The Lua VM state.
- * \return The number of elements pushed on stack.
- */
-static inline int
-luaA_object_gc(lua_State *L)
-{
-    lua_object_t *item = lua_touserdata(L, 1);
-    signal_array_wipe(&item->signals);
-    return 0;
-}
+int luaA_object_tostring(lua_State *);
+int luaA_object_gc(lua_State *);
 
 #define LUA_OBJECT_META(prefix) \
-    { "__tostring", luaA_##prefix##_tostring }, \
+    { "__tostring", luaA_object_tostring }, \
     { "add_signal", luaA_object_add_signal_simple }, \
     { "remove_signal", luaA_object_remove_signal_simple }, \
     { "emit_signal", luaA_object_emit_signal_simple },
diff --git a/image.c b/image.c
index 9e31ad29..3da494a8 100644
--- a/image.c
+++ b/image.c
@@ -27,7 +27,7 @@
 static int
 luaA_image_gc(lua_State *L)
 {
-    image_t *p = luaL_checkudata(L, 1, "image");
+    image_t *p = luaA_checkudata(L, 1, &image_class);
     imlib_context_set_image(p->image);
     imlib_free_image();
     p_delete(&p->data);
@@ -312,7 +312,7 @@ luaA_image_argb32_new(lua_State *L)
 static int
 luaA_image_orientate(lua_State *L)
 {
-    image_t *image = luaL_checkudata(L, 1, "image");
+    image_t *image = luaA_checkudata(L, 1, &image_class);
     int orientation = luaL_checknumber(L, 2);
 
     imlib_context_set_image(image->image);
@@ -334,7 +334,7 @@ luaA_image_orientate(lua_State *L)
 static int
 luaA_image_rotate(lua_State *L)
 {
-    image_t *image = luaL_checkudata(L, 1, "image"), *new;
+    image_t *image = luaA_checkudata(L, 1, &image_class), *new;
     double angle = luaL_checknumber(L, 2);
 
     new = image_new(L);
@@ -358,7 +358,7 @@ luaA_image_rotate(lua_State *L)
 static int
 luaA_image_crop(lua_State *L)
 {
-    image_t *image = luaL_checkudata(L, 1, "image"), *new;
+    image_t *image = luaA_checkudata(L, 1, &image_class), *new;
     int x = luaL_checkint(L, 2);
     int y = luaL_checkint(L, 3);
     int w = luaL_checkint(L, 4);
@@ -388,7 +388,7 @@ luaA_image_crop(lua_State *L)
 static int
 luaA_image_crop_and_scale(lua_State *L)
 {
-    image_t *image = luaL_checkudata(L, 1, "image"), *new;
+    image_t *image = luaA_checkudata(L, 1, &image_class), *new;
     int source_x = luaL_checkint(L, 2);
     int source_y = luaL_checkint(L, 3);
     int w = luaL_checkint(L, 4);
@@ -421,7 +421,7 @@ luaA_image_draw_pixel(lua_State *L)
     size_t len;
     color_t color;
     color_init_cookie_t cookie;
-    image_t *image = luaL_checkudata(L, 1, "image");
+    image_t *image = luaA_checkudata(L, 1, &image_class);
     int x = luaL_checkint(L, 2);
     int y = luaL_checkint(L, 3);
     const char *buf = luaL_checklstring(L, 4, &len);
@@ -455,7 +455,7 @@ luaA_image_draw_line(lua_State *L)
     size_t len;
     color_t color;
     color_init_cookie_t cookie;
-    image_t *image = luaL_checkudata(L, 1, "image");
+    image_t *image = luaA_checkudata(L, 1, &image_class);
     int x1 = luaL_checkint(L, 2);
     int y1 = luaL_checkint(L, 3);
     int x2 = luaL_checkint(L, 4);
@@ -492,7 +492,7 @@ luaA_image_draw_rectangle(lua_State *L)
     size_t len;
     color_t color;
     color_init_cookie_t cookie;
-    image_t *image = luaL_checkudata(L, 1, "image");
+    image_t *image = luaA_checkudata(L, 1, &image_class);
     int x = luaL_checkint(L, 2);
     int y = luaL_checkint(L, 3);
     int width  = luaL_checkint(L, 4);
@@ -584,7 +584,7 @@ luaA_table_to_color_range(lua_State *L, int ud)
 static int
 luaA_image_draw_rectangle_gradient(lua_State *L)
 {
-    image_t *image = luaL_checkudata(L, 1, "image");
+    image_t *image = luaA_checkudata(L, 1, &image_class);
     int x = luaL_checkint(L, 2);
     int y = luaL_checkint(L, 3);
     int width  = luaL_checkint(L, 4);
@@ -627,7 +627,7 @@ luaA_image_draw_circle(lua_State *L)
     size_t len;
     color_t color;
     color_init_cookie_t cookie;
-    image_t *image = luaL_checkudata(L, 1, "image");
+    image_t *image = luaA_checkudata(L, 1, &image_class);
     int x = luaL_checkint(L, 2);
     int y = luaL_checkint(L, 3);
     int ah = luaL_checkint(L, 4);
@@ -664,7 +664,7 @@ luaA_image_draw_circle(lua_State *L)
 static int
 luaA_image_save(lua_State *L)
 {
-    image_t *image = luaL_checkudata(L, 1, "image");
+    image_t *image = luaA_checkudata(L, 1, &image_class);
     const char *path = luaL_checkstring(L, 2);
     Imlib_Load_Error err;
 
@@ -697,8 +697,8 @@ luaA_image_save(lua_State *L)
 static int
 luaA_image_insert(lua_State *L)
 {
-    image_t *image_target = luaL_checkudata(L, 1, "image");
-    image_t *image_source = luaL_checkudata(L, 2, "image");
+    image_t *image_target = luaA_checkudata(L, 1, &image_class);
+    image_t *image_source = luaA_checkudata(L, 2, &image_class);
     int xoff = luaL_optnumber(L, 3, 0);
     int yoff = luaL_optnumber(L, 4, 0);
 
@@ -743,7 +743,7 @@ luaA_image_index(lua_State *L)
     if(luaA_usemetatable(L, 1, 2))
         return 1;
 
-    image_t *image = luaL_checkudata(L, 1, "image");
+    image_t *image = luaA_checkudata(L, 1, &image_class);
     size_t len;
     const char *attr = luaL_checklstring(L, 2, &len);
 
diff --git a/image.h b/image.h
index 82b69e00..08c0164c 100644
--- a/image.h
+++ b/image.h
@@ -41,7 +41,7 @@ typedef struct
 } image_t;
 
 lua_class_t image_class;
-LUA_OBJECT_FUNCS(image_class, image_t, image, "image")
+LUA_OBJECT_FUNCS(image_class, image_t, image)
 
 int image_new_from_argb32(int, int, uint32_t *);
 uint8_t * image_getdata(image_t *);
diff --git a/key.c b/key.c
index d0c5f3e7..45f9b9e4 100644
--- a/key.c
+++ b/key.c
@@ -968,7 +968,7 @@ key_getkeysym(xcb_keycode_t detail, uint16_t state)
 static void
 luaA_keystore(lua_State *L, int ud, const char *str, ssize_t len)
 {
-    keyb_t *key = luaL_checkudata(L, ud, "key");
+    keyb_t *key = luaA_checkudata(L, ud, &key_class);
     if(len)
     {
         if(*str != '#')
@@ -1063,7 +1063,7 @@ luaA_key_array_set(lua_State *L, int oidx, int idx, key_array_t *keys)
 
     lua_pushnil(L);
     while(lua_next(L, idx))
-        if(luaA_toudata(L, -1, "key"))
+        if(luaA_toudata(L, -1, &key_class))
             key_array_append(keys, luaA_object_ref_item(L, oidx, -1));
         else
             lua_pop(L, 1);
diff --git a/key.h b/key.h
index 7d8ede97..ef973c2c 100644
--- a/key.h
+++ b/key.h
@@ -19,8 +19,8 @@
  *
  */
 
-#ifndef AWESOME_KEYBINDING_H
-#define AWESOME_KEYBINDING_H
+#ifndef AWESOME_KEY_H
+#define AWESOME_KEY_H
 
 #include "luaa.h"
 
@@ -36,7 +36,7 @@ typedef struct keyb_t
 } keyb_t;
 
 lua_class_t key_class;
-LUA_OBJECT_FUNCS(key_class, keyb_t, key, "key")
+LUA_OBJECT_FUNCS(key_class, keyb_t, key)
 DO_ARRAY(keyb_t *, key, DO_NOTHING)
 
 void key_class_setup(lua_State *);
diff --git a/luaa.c b/luaa.c
index a7790246..a5bef8f7 100644
--- a/luaa.c
+++ b/luaa.c
@@ -345,7 +345,7 @@ luaA_wtable_newindex(lua_State *L)
     /* get current key value in content table */
     lua_rawget(L, lua_upvalueindex(1));
     /* if value is a widget, notify change */
-    if(lua_istable(L, -1) || luaA_toudata(L, -1, "widget"))
+    if(lua_istable(L, -1) || luaA_toudata(L, -1, &widget_class))
         invalid = true;
 
     lua_pop(L, 1); /* remove value */
@@ -356,7 +356,7 @@ luaA_wtable_newindex(lua_State *L)
         luaA_table2wtable(L);
         invalid = true;
     }
-    else if(!invalid && luaA_toudata(L, 3, "widget"))
+    else if(!invalid && luaA_toudata(L, 3, &widget_class))
         invalid = true;
 
     /* upvalue 1 is content table */
diff --git a/tag.c b/tag.c
index bd9d6712..a3dc4d4c 100644
--- a/tag.c
+++ b/tag.c
@@ -26,7 +26,7 @@
 #include "widget.h"
 
 static lua_class_t tag_class;
-LUA_OBJECT_FUNCS(tag_class, tag_t, tag, "tag")
+LUA_OBJECT_FUNCS(tag_class, tag_t, tag)
 
 void
 tag_unref_simplified(tag_t **tag)
@@ -41,7 +41,7 @@ tag_unref_simplified(tag_t **tag)
 static int
 luaA_tag_gc(lua_State *L)
 {
-    tag_t *tag = luaL_checkudata(L, 1, "tag");
+    tag_t *tag = luaA_checkudata(L, 1, &tag_class);
     client_array_wipe(&tag->clients);
     p_delete(&tag->name);
     return luaA_object_gc(L);
@@ -55,7 +55,7 @@ luaA_tag_gc(lua_State *L)
 static void
 tag_view(lua_State *L, int udx, bool view)
 {
-    tag_t *tag = luaL_checkudata(L, udx, "tag");
+    tag_t *tag = luaA_checkudata(L, udx, &tag_class);
     if(tag->selected != view)
     {
         tag->selected = view;
@@ -92,7 +92,7 @@ tag_view(lua_State *L, int udx, bool view)
 void
 tag_append_to_screen(lua_State *L, int udx, screen_t *s)
 {
-    tag_t *tag = luaL_checkudata(globalconf.L, udx, "tag");
+    tag_t *tag = luaA_checkudata(globalconf.L, udx, &tag_class);
 
     /* can't attach a tag twice */
     if(tag->screen)
@@ -306,7 +306,7 @@ luaA_tag_new(lua_State *L)
 static int
 luaA_tag_clients(lua_State *L)
 {
-    tag_t *tag = luaL_checkudata(L, 1, "tag");
+    tag_t *tag = luaA_checkudata(L, 1, &tag_class);
     client_array_t *clients = &tag->clients;
     int i;
 
diff --git a/timer.c b/timer.c
index 9ca41dfe..f3acc28d 100644
--- a/timer.c
+++ b/timer.c
@@ -33,7 +33,7 @@ typedef struct
 } atimer_t;
 
 static lua_class_t timer_class;
-LUA_OBJECT_FUNCS(timer_class, atimer_t, timer, "timer")
+LUA_OBJECT_FUNCS(timer_class, atimer_t, timer)
 
 static void
 ev_timer_emit_signal(struct ev_loop *loop, struct ev_timer *w, int revents)
@@ -47,7 +47,7 @@ static int
 luaA_timer_new(lua_State *L)
 {
     luaA_class_new(L, &timer_class);
-    atimer_t *timer = luaL_checkudata(L, -1, "timer");
+    atimer_t *timer = luaA_checkudata(L, -1, &timer_class);
     timer->timer.data = timer;
     ev_set_cb(&timer->timer, ev_timer_emit_signal);
     return 1;
@@ -72,7 +72,7 @@ luaA_timer_get_timeout(lua_State *L, atimer_t *timer)
 static int
 luaA_timer_start(lua_State *L)
 {
-    atimer_t *timer = luaL_checkudata(L, 1, "timer");
+    atimer_t *timer = luaA_checkudata(L, 1, &timer_class);
     if(timer->started)
         luaA_warn(L, "timer already started");
     else
@@ -87,7 +87,7 @@ luaA_timer_start(lua_State *L)
 static int
 luaA_timer_stop(lua_State *L)
 {
-    atimer_t *timer = luaL_checkudata(L, 1, "timer");
+    atimer_t *timer = luaA_checkudata(L, 1, &timer_class);
     if(timer->started)
     {
         ev_timer_stop(globalconf.loop, &timer->timer);
diff --git a/wibox.c b/wibox.c
index 56379b72..905cbd84 100644
--- a/wibox.c
+++ b/wibox.c
@@ -37,7 +37,7 @@
 static int
 luaA_wibox_gc(lua_State *L)
 {
-    wibox_t *wibox = luaL_checkudata(L, 1, "wibox");
+    wibox_t *wibox = luaA_checkudata(L, 1, &wibox_class);
     p_delete(&wibox->cursor);
     wibox_wipe(wibox);
     button_array_wipe(&wibox->buttons);
@@ -839,7 +839,7 @@ static int
 luaA_wibox_index(lua_State *L)
 {
     size_t len;
-    wibox_t *wibox = luaL_checkudata(L, 1, "wibox");
+    wibox_t *wibox = luaA_checkudata(L, 1, &wibox_class);
     const char *attr = luaL_checklstring(L, 2, &len);
 
     if(luaA_usemetatable(L, 1, 2))
@@ -924,7 +924,7 @@ luaA_wibox_index(lua_State *L)
 static int
 luaA_wibox_geometry(lua_State *L)
 {
-    wibox_t *wibox = luaL_checkudata(L, 1, "wibox");
+    wibox_t *wibox = luaA_checkudata(L, 1, &wibox_class);
 
     if(lua_gettop(L) == 2)
     {
@@ -961,7 +961,7 @@ static int
 luaA_wibox_newindex(lua_State *L)
 {
     size_t len;
-    wibox_t *wibox = luaL_checkudata(L, 1, "wibox");
+    wibox_t *wibox = luaA_checkudata(L, 1, &wibox_class);
     const char *buf, *attr = luaL_checklstring(L, 2, &len);
     awesome_token_t tok;
 
@@ -1153,7 +1153,7 @@ luaA_wibox_newindex(lua_State *L)
 static int
 luaA_wibox_buttons(lua_State *L)
 {
-    wibox_t *wibox = luaL_checkudata(L, 1, "wibox");
+    wibox_t *wibox = luaA_checkudata(L, 1, &wibox_class);
 
     if(lua_gettop(L) == 2)
     {
diff --git a/wibox.h b/wibox.h
index ce7b109a..6c17e402 100644
--- a/wibox.h
+++ b/wibox.h
@@ -117,7 +117,7 @@ void wibox_border_color_set(wibox_t *, const xcolor_t *);
 void wibox_orientation_set(wibox_t *, orientation_t);
 
 lua_class_t wibox_class;
-LUA_OBJECT_FUNCS(wibox_class, wibox_t, wibox, "wibox")
+LUA_OBJECT_FUNCS(wibox_class, wibox_t, wibox)
 
 #endif
 // vim: filetype=c:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=80
diff --git a/widget.c b/widget.c
index 31a6e5fd..25b8f2c7 100644
--- a/widget.c
+++ b/widget.c
@@ -32,8 +32,7 @@
 #include "common/atoms.h"
 #include "common/xutil.h"
 
-static lua_class_t widget_class;
-LUA_OBJECT_FUNCS(widget_class, widget_t, widget, "widget");
+LUA_OBJECT_FUNCS(widget_class, widget_t, widget);
 
 /** Collect a widget structure.
  * \param L The Lua VM state.
@@ -42,7 +41,7 @@ LUA_OBJECT_FUNCS(widget_class, widget_t, widget, "widget");
 static int
 luaA_widget_gc(lua_State *L)
 {
-    widget_t *widget = luaL_checkudata(L, 1, "widget");
+    widget_t *widget = luaA_checkudata(L, 1, &widget_class);
     if(widget->destructor)
         widget->destructor(widget);
     button_array_wipe(&widget->buttons);
@@ -115,7 +114,7 @@ luaA_table2widgets(lua_State *L, widget_node_array_t *widgets)
     }
     else
     {
-        widget_t *widget = luaA_toudata(L, -1, "widget");
+        widget_t *widget = luaA_toudata(L, -1, &widget_class);
         if(widget)
         {
             widget_node_t w;
@@ -405,7 +404,7 @@ luaA_widget_new(lua_State *L)
 {
     luaA_class_new(L, &widget_class);
 
-    widget_t *w = luaL_checkudata(L, -1, "widget");
+    widget_t *w = luaA_checkudata(L, -1, &widget_class);
     /* Set visible by default. */
     w->isvisible = true;
 
@@ -423,7 +422,7 @@ luaA_widget_new(lua_State *L)
 static int
 luaA_widget_buttons(lua_State *L)
 {
-    widget_t *widget = luaL_checkudata(L, 1, "widget");
+    widget_t *widget = luaA_checkudata(L, 1, &widget_class);
 
     if(lua_gettop(L) == 2)
     {
@@ -455,7 +454,7 @@ luaA_widget_index(lua_State *L)
         return 1;
 
     /* Then call special widget index */
-    widget_t *widget = luaL_checkudata(L, 1, "widget");
+    widget_t *widget = luaA_checkudata(L, 1, &widget_class);
     return widget->index ? widget->index(L, token) : 0;
 }
 
@@ -474,14 +473,14 @@ luaA_widget_newindex(lua_State *L)
     luaA_class_newindex(L);
 
     /* Then call special widget newindex */
-    widget_t *widget = luaL_checkudata(L, 1, "widget");
+    widget_t *widget = luaA_checkudata(L, 1, &widget_class);
     return widget->newindex ? widget->newindex(L, token) : 0;
 }
 
 static int
 luaA_widget_extents(lua_State *L)
 {
-    widget_t *widget = luaL_checkudata(L, 1, "widget");
+    widget_t *widget = luaA_checkudata(L, 1, &widget_class);
     area_t g = {
         .x = 0,
         .y = 0,
diff --git a/widget.h b/widget.h
index c4b8d3a5..2d6aec5d 100644
--- a/widget.h
+++ b/widget.h
@@ -69,6 +69,7 @@ bool widget_geometries(wibox_t *);
 void widget_invalidate_bywidget(widget_t *);
 void widget_invalidate_bytype(widget_constructor_t *);
 
+lua_class_t widget_class;
 void widget_class_setup(lua_State *);
 
 widget_constructor_t widget_textbox;
diff --git a/widgets/graph.c b/widgets/graph.c
index 878a1ac7..771508a1 100644
--- a/widgets/graph.c
+++ b/widgets/graph.c
@@ -305,7 +305,7 @@ graph_draw(widget_t *widget, draw_context_t *ctx,
 static int
 luaA_graph_plot_properties_set(lua_State *L)
 {
-    widget_t *widget = luaL_checkudata(L, 1, "widget");
+    widget_t *widget = luaA_checkudata(L, 1, &widget_class);
     graph_data_t *d = widget->data;
     float max_value;
     const char *title, *buf;
@@ -370,7 +370,7 @@ luaA_graph_plot_properties_set(lua_State *L)
 static int
 luaA_graph_plot_data_add(lua_State *L)
 {
-    widget_t *widget = luaL_checkudata(L, 1, "widget");
+    widget_t *widget = luaA_checkudata(L, 1, &widget_class);
     graph_data_t *d = widget->data;
     plot_t *plot = NULL;
     const char *title = luaL_checkstring(L, 2);
@@ -448,7 +448,7 @@ luaA_graph_plot_data_add(lua_State *L)
 static int
 luaA_graph_index(lua_State *L, awesome_token_t token)
 {
-    widget_t *widget = luaL_checkudata(L, 1, "widget");
+    widget_t *widget = luaA_checkudata(L, 1, &widget_class);
     graph_data_t *d = widget->data;
 
     switch(token)
@@ -500,7 +500,7 @@ static int
 luaA_graph_newindex(lua_State *L, awesome_token_t token)
 {
     size_t len;
-    widget_t *widget = luaL_checkudata(L, 1, "widget");
+    widget_t *widget = luaA_checkudata(L, 1, &widget_class);
     graph_data_t *d = widget->data;
     const char *buf;
     int width;
diff --git a/widgets/imagebox.c b/widgets/imagebox.c
index 16306549..e5aedf77 100644
--- a/widgets/imagebox.c
+++ b/widgets/imagebox.c
@@ -102,7 +102,7 @@ imagebox_destructor(widget_t *w)
 static int
 luaA_imagebox_index(lua_State *L, awesome_token_t token)
 {
-    widget_t *widget = luaL_checkudata(L, 1, "widget");
+    widget_t *widget = luaA_checkudata(L, 1, &widget_class);
     imagebox_data_t *d = widget->data;
 
     switch(token)
@@ -131,7 +131,7 @@ luaA_imagebox_index(lua_State *L, awesome_token_t token)
 static int
 luaA_imagebox_newindex(lua_State *L, awesome_token_t token)
 {
-    widget_t *widget = luaL_checkudata(L, 1, "widget");
+    widget_t *widget = luaA_checkudata(L, 1, &widget_class);
     imagebox_data_t *d = widget->data;
 
     switch(token)
diff --git a/widgets/progressbar.c b/widgets/progressbar.c
index afb48fa0..11cfef8f 100644
--- a/widgets/progressbar.c
+++ b/widgets/progressbar.c
@@ -443,7 +443,7 @@ static int
 luaA_progressbar_bar_properties_set(lua_State *L)
 {
     size_t len;
-    widget_t *widget = luaL_checkudata(L, 1, "widget");
+    widget_t *widget = luaA_checkudata(L, 1, &widget_class);
     const char *buf, *title = luaL_checkstring(L, 2);
     bar_t *bar;
     progressbar_data_t *d = widget->data;
@@ -508,7 +508,7 @@ luaA_progressbar_bar_properties_set(lua_State *L)
 static int
 luaA_progressbar_bar_data_add(lua_State *L)
 {
-    widget_t *widget = luaL_checkudata(L, 1, "widget");
+    widget_t *widget = luaA_checkudata(L, 1, &widget_class);
     const char *title = luaL_checkstring(L, 2);
     progressbar_data_t *d = widget->data;
     bar_t *bar;
@@ -543,7 +543,7 @@ luaA_progressbar_bar_data_add(lua_State *L)
 static int
 luaA_progressbar_index(lua_State *L, awesome_token_t token)
 {
-    widget_t *widget = luaL_checkudata(L, 1, "widget");
+    widget_t *widget = luaA_checkudata(L, 1, &widget_class);
     progressbar_data_t *d = widget->data;
 
     switch(token)
@@ -593,7 +593,7 @@ luaA_progressbar_index(lua_State *L, awesome_token_t token)
 static int
 luaA_progressbar_newindex(lua_State *L, awesome_token_t token)
 {
-    widget_t *widget = luaL_checkudata(L, 1, "widget");
+    widget_t *widget = luaA_checkudata(L, 1, &widget_class);
     progressbar_data_t *d = widget->data;
 
     switch(token)
diff --git a/widgets/textbox.c b/widgets/textbox.c
index 72d69cc0..175616f3 100644
--- a/widgets/textbox.c
+++ b/widgets/textbox.c
@@ -145,7 +145,7 @@ textbox_destructor(widget_t *w)
 static int
 luaA_textbox_margin(lua_State *L)
 {
-    widget_t *widget = luaL_checkudata(L, 1, "widget");
+    widget_t *widget = luaA_checkudata(L, 1, &widget_class);
     textbox_data_t *d = widget->data;
 
     if(lua_gettop(L) == 2)
@@ -178,7 +178,7 @@ luaA_textbox_margin(lua_State *L)
 static int
 luaA_textbox_index(lua_State *L, awesome_token_t token)
 {
-    widget_t *widget = luaL_checkudata(L, 1, "widget");
+    widget_t *widget = luaA_checkudata(L, 1, &widget_class);
     textbox_data_t *d = widget->data;
 
     switch(token)
@@ -257,7 +257,7 @@ static int
 luaA_textbox_newindex(lua_State *L, awesome_token_t token)
 {
     size_t len = 0;
-    widget_t *widget = luaL_checkudata(L, 1, "widget");
+    widget_t *widget = luaA_checkudata(L, 1, &widget_class);
     const char *buf = NULL;
     textbox_data_t *d = widget->data;