Question: supplying C++ user data about luabridge3 HOT 7 CLOSED

int proxySetter(lua_State* L)
{
   tinyxml2::XMLNode* node = luabridge::Stack<tinyxml2::XMLNode*>::get(L, 1).value();
   luabridge::LuaRef data = luabridge::Stack<luabridge::LuaRef>::get(L, 2).value();
   int ref = ??? // do some magic with the LuaRef, presumably to get the Lua registry index. not sure.
   node->SetUserData(reinterpret_cast<void*>(ref));
   return 0;
}

int proxyGetter(lua_State *L)
{
   const tinyxml2::XMLNode* node = luabridge::Stack<const tinyxml2::XMLNode*>::get(L, 1).value();
   int ref = reinterpret_cast<int>(node->GetUserData());
   if (!ref)
      lua_pushnil(L);
   else
   {
      luabridge::LuaRef data = ??? // do some magic with the ref to hydrate a LuaRef from the Lua registry index
      // if it has been garbage collected, we push nil, otherwise:
      luabridge::Stack<luabridge::LuaRef>::push(L, data).throw_on_error();
   }
   return 1;
}

// Setup
lua_newtable(L);
lua_newtable(L);
lua_pushstring(L, "v");
lua_setfield(L, -2, "__mode");
lua_setmetatable(L, -2);
lua_setfield(L, LUA_REGISTRYINDEX, "__xml_user_data");

// Set
tinyxml2::XMLNode* node = luabridge::Stack<tinyxml2::XMLNode*>::get(L, 1).value();

lua_getfield(L, LUA_REGISTRYINDEX, "__xml_user_data");
lua_pushlightuserdata(L, node);
lua_pushvalue(L, 2); // the lua object you want to store
lua_settable(L, -3);

// Get
tinyxml2::XMLNode* node = luabridge::Stack<tinyxml2::XMLNode*>::get(L, 1).value();

lua_getfield(L, LUA_REGISTRYINDEX, "__xml_user_data");
lua_pushlightuserdata(L, node);
lua_gettable(L, -2);

// Setup
lua_newtable(L);
lua_newtable(L);
lua_pushstring(L, "k");
lua_setfield(L, -2, "__mode");
lua_setmetatable(L, -2);
lua_setfield(L, LUA_REGISTRYINDEX, "__xml_user_data");

// Set
lua_getfield(L, LUA_REGISTRYINDEX, "__xml_user_data");
lua_pushvalue(L, 1); // the tinyxml2::XMLNode* as key
lua_pushvalue(L, 2); // the lua object you want to store as value
lua_settable(L, -3);

// Get
lua_getfield(L, LUA_REGISTRYINDEX, "__xml_user_data");
lua_pushvalue(L, 1); // the tinyxml2::XMLNode* as key
lua_gettable(L, -2);