Re: closure upvalues

[Ignacio Castaño <castanyo@...>]

Ignacio Castaño wrote:
> Roberto Ierusalimschy wrote:
> > > Is it possible to get the closure upvalues without calling it?
> >
> > No (maybe we will add this facility to the API).
>
> It would be really usefull, specially now, that it's quite elegant to bind
a
> metatable to a class constructor to create objects of that class. I don't
> know much about lua internals, but I'll try to do it myself...

well, I've done it. I will test it now, but I'll throw it here in case
someone sees something wrong...


LUA_API void lua_getupvalue (lua_State *L, int index, int upvalue) {
  StkId o;
  lua_lock(L);
  o = luaA_indexAcceptable(L, index);
  if( o==NULL || !iscfunction(o) )
    setnilvalue(L->top);
  else {
    Closure *cl = clvalue(o);
    if( upvalue<0 || upvalue >= cl->c.nupvalues )
      setnilvalue(L->top);
 else
      setobj(L->top, &cl->c.upvalue[upvalue]);
  }
  api_incr_top(L);
  lua_unlock(L);
}



Ignacio Castaño
castanyo@yahoo.es




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