Re: lua_getupvalue question

[Andrew Starks <andrew.starks@...>]

On Monday, December 2, 2013, Sean Conner  wrote:
> It was thus said that the Great Andrew Starks once stated:
>
> > Given the following:
> >
> > ```
> > int iter(lua_State *L){
> >   ///what to do here?
> >     lua_pushinteger(L, (lua_Integer) luaL_checkint(L,
> > lua_upvalueindex(1)) + 1); //I can get the upvalue...
> >     // how do I set it?
> >     //lua_getupvalue (lua_State *L, int funcindex, int n); //doesn't
> > seem like the correct function because iter is not on the stack, at
> > this point.
> > }
> >
> > int factory(lua_State *L){
> >   lua_pushnumber(L, 0);
> >   lua_pushcclosure(L, iter, 1);
> >   return 1;
> > }
> >
> > ```
> >
> > My question is, how do you change the value of an upvalue when you are
> > in the C closure that has the upvalue? You can get it, but how does
> > one set it? I didn't see a pseudo index for it.
> >
> > I'm sure I'm missing something really basic.
>
>   You want to call ua_upvalueindex().  That will return an index you can
> pass to other Lua functions that take an index.  It's described in section
> 3.4 of Lua 5.1 and section 4.4 of Lua 5.2.
>
>   -spc

I messed up. It's setupvalue not get. 

-Andrew