Re: lua_getupvalue question

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

On Monday, December 2, 2013, Philipp Janda  wrote:
> Am 03.12.2013 02:00 schröbte 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;
> > > > }
> > > >
> > > > ```
> > >
> > >    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.
>
> That may be true, but given your description you probably wanted `lua_replace(L, lua_upvalueindex(1))` anyway as Sean suggested (sort of) ...
>
> > -Andrew
>
> Philipp

I get the upvalue. It's on the stack. It's value is 0. I want it so that the next time I enter the c function and retrieve the value at the same lua_upvalueindex address, it returns unto me the previous value, added to one. 

Please to illustrate?

-Andrew