Lua OOP initiative (Re: RES: RES: idea of vision of blueprint of ROADMAP of Lua core)

[Asko Kauppi <asko.kauppi@...>]

Could we start an 'inner circle' discussion & workgroup on this?

I don't know the 'answer' but I do know the need, and I'd be able to 
test out approaches in LuaX environment.  Personally, I wouldn't start 
by demanding language (core) changes, rather just coming up with a 
working add-on, and if _then_ we find there's a crucial 
syntax/performance bottleneck, let's bring it up.

My requirements for this thing would be, that it's totally generic and 
loadable. Like:

	local obj= require "obj_support"	-- building blocks for other modules
	...
	local myclass_new= function(...)
		local o= obj.new( ... )
		...

The end user wouldn't (need to) see 'obj_support' but any OO modules 
would get smaller, by letting it do the administrative/oo specific work 
for them.

Am I in?

-ak



16.1.2005 kello 08:04, André de Leiradella kirjoitti:

 lua-bounces@bazar2.conectiva.com.br wrote:
> > André de Leiradella wrote:
> > > + Classes and objects
> > >
> > > It's #1 to me. This seems to be a common wish, every now and then we
> > > see threads on this topic and many people have developed workarounds
> > > so that it looks like Lua is a real OOP language, and (or as) the
> > > game programing community uses C++ a lot. It's not necessary to add
> > > predefined classes to the core (like Java's VM that rely on String
> > > and StringBuffer at least), just the ability to define classes,
> > > instantiate objects and calling [inherited] methods.
> >
> > This is very possible... there are various ways to do it, but that's
> > what metaprogramming is about.  Regardless of how you get there you
> > end up with something about as elegant as you could ask for
> > (obj:method(), obj.attribute), but you have to 'do it yourself'
> > (though a simple implementation is already very simple).  So I can't
> > see a 'blessed' way of doing this making it to the core, but I assume
> > it's already well-covered by projects such as LuaCheia (and
> > definitely amply covered by the Wiki code).
> >
> > --Adam
>
> I've done it myself, and I'm not happy. I've seen how others did it
> themselves, and I'm still not happy. Unless I'm missing something, I
> don't see a way to get rid of the self local that must prefix every
> property of the "class", making me write self.this and self.that. I
> don't see an elegant way to call inherited methods like
> super.something(...) or inherited something(...), but only hacks like
> self.super.something(self, ...) or SuperClassName.something(self, ...).
> I don't like that users of my applications get stuck because they don't
> remember where they should use 'obj.' or 'obj:'.
>
> The "blessed" way of doing it would come up from the community just 
> like
> the packaging system. OOP in Lua would add very little to the core and
> make the language a great choice for many applications that require it.
> I'd like to stress this: there is no small scripting language with OOP,
> I've been looking to many options and they're all bloated with modules.
>
> Please let's not start discussing what OOP is, I'd be more than happy
> with classes (that would be first class values, of course) and
> instances, getting rid of the self prefix for all properties, a 
> standard
> way to call inherited methods; static (or class) methods and properties
> and access previledges would be an welcome bonus.
>
> I *think* that the keyword "new" was reserved in Lua 4, wasn't it? It
> made me think that maybe OOP was in its way for Lua 5 :(
>
> Regards,
>
> Andre de Leiradella