Re: Inheriting from C++ Classes

[Ignacio Burgueño <ignaciob@...>]

Leo Razoumov wrote:
> On Fri, 23 Jan 2009, Ignacio Burgueño wrote:
> > [..snip..]
>
> What is the purpose of
>
> typedef int (T::*mfp)(lua_State* L);
>
> Type mpf refers to a C++ member function of class T and cannot be made 
> into Lua C-closure because it implicitly passes this-pointer as an extra 
> argument.

Indeed, its not made into a closure. It is used instead by this function:
static int thunk_methods(lua_State* L) {
		// stack has userdata, followed by method args
		T* obj = Base::check(L, 1);  // get 'self', or if you prefer, 'this'
		//lua_remove(L, 1);  // remove self so member function args start at 
index 1
		// get member function from upvalue
		RegType* l = static_cast<RegType*>(lua_touserdata(L, 
lua_upvalueindex(1)));
		return (obj->*(l->mfunc))(L);  // call member function
	}


l->mfunc is of type mfp, and the function thunk_methods is the c closure 
indeed.

Regards,
Ignacio