From: Trans <transfire@...>
Date: 2007-10-17T04:43:58+09:00
Subject: Re: RubyTraits 0.1



On Oct 15, 8:38 am, Yukihiro Matsumoto <m...@ruby-lang.org> wrote:
> Hi,
>
> In message "Re: RubyTraits 0.1"
>     on Tue, 16 Oct 2007 00:23:43 +0900, Trans <transf...@gmail.com> writes:
>
> |I see. So you don't really like the fact that modules fit into the
> |inheritance chain? That's interesting.
>
> Actually they both have their own good.  I like them both.  I dislike
> to have them both in a language.  Traits injection is clear and less
> error prone (there's no possibility of conflicts), but sometimes
> method overriding is _very_ useful, where aliasing is very poor way to
> create method combination.
>
> If someone come to the idea to allow modules to have merits from both
> mixins and traits at once (without demerit), I'd love to hear.

I couldn't help but think about what a solution to that might look
like --it would have to have the layerability of modules but the
simplicity of traits. To do that, I think methods would have to be
more independent. Instead of a Method being a single function
belonging to class (or module/trait) it would be a linked-list of
them. Each of these would have a second link tying it to the trait/
module. Eg.

      .-> Class1
      |                .-> TraitX     .-> TraitY
   .--------           |              |
   | -> foo_method-> foo_method -> foo_method
   '--------

It would also be possible to do around advice very easily too, because
a method could be added to the chain that's not tied to a Triat/
Module.

      .-> Class1
      |                              .-> TraitX    .-> TraitY
   .--------                         |             |
   | -> foo_method -> foo_method -> foo_method -> foo_method
   '--------

#super would be dynamically resolved by following the link.

I think this could provide the advantages of both traits and modules
in a single system.

T.