__type metamethod

stepmania/src/lua-5.1/src/lauxlib.c

@@ -57,10 +57,18 @@ LUALIB_API int luaL_argerror (lua_State *L, int narg, const char *extramsg) {
                         narg, ar.name, extramsg);
 }
 
+LUALIB_API int luaL_pushtype (lua_State *L, int narg) {
+  if (!luaL_callmeta(L, narg, "__type"))
+    lua_pushstring (L, luaL_typename(L, narg));
+
+  return 1;
+}
 
 LUALIB_API int luaL_typerror (lua_State *L, int narg, const char *tname) {
-  const char *msg = lua_pushfstring(L, "%s expected, got %s",
+  const char *msg;
-                                    tname, luaL_typename(L, narg));
+  luaL_pushtype(L, narg);
+  msg = lua_pushfstring(L, "%s expected, got %s",
+                                    tname, lua_tostring(L, -1));
   return luaL_argerror(L, narg, msg);
 }
 

stepmania/src/lua-5.1/src/lauxlib.h

@@ -107,6 +107,7 @@ LUALIB_API const char *(luaL_findtable) (lua_State *L, int idx,
 #define luaL_optlong(L,n,d)	((long)luaL_optinteger(L, (n), (d)))
 
 #define luaL_typename(L,i)	lua_typename(L, lua_type(L,(i)))
+LUALIB_API int (luaL_pushtype) (lua_State *L, int idx);
 
 #define luaL_dofile(L, fn) \
 	(luaL_loadfile(L, fn) || lua_pcall(L, 0, LUA_MULTRET, 0))