LuaInterface.LuaDLL.lua_isnil C# (CSharp) Method

        public static bool lua_isnil(IntPtr luaState, int index)
        {
            return (LuaDLL.lua_type(luaState, index) == LuaTypes.LUA_TNIL);
        }

        public void PushNewValueObject(IntPtr luaState, object o, int index)
        {
            LuaDLL.luanet_newudata(luaState, index);

            //string meta = GetAQName(o.GetType());
            //LuaDLL.luaL_getmetatable(luaState, meta);
            Type t = o.GetType();
            PushMetaTable(luaState, o.GetType());

            if (LuaDLL.lua_isnil(luaState, -1))
            {
                string meta = t.AssemblyQualifiedName;
                Debugger.LogError("Create not wrap ulua type:" + meta);
                LuaDLL.lua_settop(luaState, -2);
                LuaDLL.luaL_newmetatable(luaState, meta);
                LuaDLL.lua_pushstring(luaState, "cache");
                LuaDLL.lua_newtable(luaState);
                LuaDLL.lua_rawset(luaState, -3);
                LuaDLL.lua_pushlightuserdata(luaState, LuaDLL.luanet_gettag());
                LuaDLL.lua_pushnumber(luaState, 1);
                LuaDLL.lua_rawset(luaState, -3);
                LuaDLL.lua_pushstring(luaState, "__index");
                LuaDLL.lua_pushstring(luaState, "luaNet_indexfunction");
                LuaDLL.lua_rawget(luaState, (int)LuaIndexes.LUA_REGISTRYINDEX);
                LuaDLL.lua_rawset(luaState, -3);
                LuaDLL.lua_pushstring(luaState, "__gc");
                LuaDLL.lua_pushstdcallcfunction(luaState, metaFunctions.gcFunction);
                LuaDLL.lua_rawset(luaState, -3);
                LuaDLL.lua_pushstring(luaState, "__tostring");
                LuaDLL.lua_pushstdcallcfunction(luaState, metaFunctions.toStringFunction);
                LuaDLL.lua_rawset(luaState, -3);
                LuaDLL.lua_pushstring(luaState, "__newindex");
                LuaDLL.lua_pushstdcallcfunction(luaState, metaFunctions.newindexFunction);
                LuaDLL.lua_rawset(luaState, -3);
            }

            LuaDLL.lua_setmetatable(luaState, -2);
        }