Re: Inheritance

[Florian Weimer <fw@...>]

* Christoph Schreiber:

> Here is the full function. I don't understand how lua knows which
> base class to call. I return only the method name. I always thougt
> the return value (1 in this case) tells lua how many values I return
> on the stack.
>
> int ChildClass::index(lua_State* L)
> {
>     // searches for the method in child's metatable
>     const char* key = luaL_checkstring(L, 2);
>     lua_getmetatable(L, 1);
>     lua_getfield(L, -1, key);
>
>     // if it doesn't find the method it calls 
>     // the method of the base class
>     if(lua_isnil(L, -1))
>     {
>         luaL_getmetatable(L, BaseClass::classId);
>         lua_getfield(L, -1, key);
>     }
>     return 1;
> }

I think it just gets the base class's metatable from the registry,
using the string BaseClass::classId.  Note that lua_getmetatable and
luaL_getmetatable are different functions.