Re: void* in Lua_State for Application?

[William Ahern <william@...>]

On Tue, Sep 10, 2013 at 11:48:45AM -0700, William Ahern wrote:
> On Tue, Sep 10, 2013 at 11:37:03PM +0900, Miles Bader wrote:
> > Tim Hill <drtimhill@gmail.com> writes:
> > > It's pretty late here, but looking at your code isn't it always trying
> > > to get not-present values? If so, I'm not sure if this can be extended
> > > to Lua behavior when it gets values that are present in the Registry?
> > 
> > Indeed, and for the "integer" case, it uses huge integers, not the
> > smallish integers you'd normally use.
> > 
> > I've modified the example program (see attachment) to use a more
> > realistic case of a small number of already-present entries , and added
> > tests for string accesses (using both lua_rawget and lua_getfield) too.
> > 
> > Here's the results I get (which granted, are likely on a different CPU
> > etc than William used):
> 
<snip>
> I dunno... this seems all so very inconsequential. Using lightuserdata seems
> very simple and clean (unlike string keys), and still perfectly performant.
> But, I guess suum cuique pulchrum est.

I take that back. The more I think about it the more using upvalues make
sense.

But when I use lightuserdata, I can keep all the logic highly localized.
Like

	lua_pushlightuserdata(L, &key);
	lua_gettable(L, LUA_REGISTRYINDEX);

	if (lua_isnil(L, -1)) {
		// initialize cache, etc
	}

	// use cache, etc

and most of my functions are defined using simple luaL_Reg arrays, so the
luaopen routine has no knowledge of what's happening. Is there a standard
pattern you use when defining your module's functions, or do you usually
single functions out one-by-one to be defined as a C closure outside the
normal loading code?