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- Subject: Re: Overloading Library Functions in the Registry
- From: Lavergne Thomas <thomas.lavergne@...>
- Date: Wed, 5 Sep 2007 14:13:35 +0200
Try something like this :
lua_getglobal(L, LUA_LIBNAME); -- get the table of the library
lua_getfield(L, -1, "functionname"); -- get the old function
lua_pushcclosure(L, function, 1); -- push the overloaded function
-- with upvalue to the old
lua_setfield(L, -2, "functionname); set it to the library table
So when your new function is called, you have the in an upvalue in the
closure so you can retrieve it at index lua_upvalueindex(1) in the
Hope this help you
On Wed, Sep 05, 2007 at 12:11:11PM +0200, Eva Schmidt wrote:
> I want to overload or extend an existing function (stored in the __index
> table) from a library. I want to do this from my C-program, NOT from Lua.
> Maybe I don't see the woods for the trees, but how can I access this
> metatable and manipulate a function in it?
> I want to extend a certain function at the time of initializing (after
> opening the libraries) to connect this function call in Lua with a call of
> one of my own functions...
> I think it must be something like that:
> lua_getglobal (L, LUA_LIBNAME); -- get the table of the library
> lua_pushstring (L, "functionname") -- push the name
> lua_pushcfunction (L, function) -- push the overloaded function
> lua_settable (L, -3) -- set it to the library table
> I think this should overwrite the whole function with my own code. But I
> really want to extend the old function. Probably I need to call the old
> function from my new?!
> Maybe somebody has already done something like that and has some hints or
> ideas for me?
> Thanks a lot!
Thomas Lavergne "Le vrai rêveur est celui qui rêve
de l'impossible." (Elsa Triolet)