Setting userdata as namespace in Lua

[Agustín Cordes <agustin@...>]

Hi all,

I have researched this subject and tried various approaches but I can't implement the behavior I have in mind (I'm not even sure it's possible). Basically, I have several userdata objects created in C that can be accessed by their metatable, like this:

Main.lua
--------

config.display_width = 1280

What I'd like to do is to "force" the config namespace to a specific script. You've guessed it, I need to protect a configuration file so that users are restricted to deal only with the config metatable. Like this:

Config.lua
----------

display_width = 1280

And I know I have to do something like this in C:

// Register the config metatable and its methods
luaL_loadfile(L, "my_config.cfg");
lua_getglobal(L, "config"); // Is this necessary?
lua_setfenv(L, -2); // I know this has to be used, but how?
lua_pcall(L, 0, 0, 0);

Thank you in advance, this one is driving me crazy!

Agustín

PS: For the record, I really need to keep the config userdata as it is because it's binded to a C structure. In consequence, I'm not concerned about "losing" the Lua state or declared variables between different environments.