From: SonOfLilit <sonoflilit@...>
Date: 2007-02-18T21:10:00+09:00
Subject: Re: More flexible inheritance

Wouldn't this hurt performance a lot? For each and every message
passed, one more step in lookup.

I don't know.

Aur Saraf

On 2/18/07, Trans <transfire@gmail.com> wrote:
> A notion came to me yesterday with regards to how we extend classes.
> On the one hand we can create a module and include it into a class,
> but this will not allow us to override a preexisting method -- for
> that we must reopen the class and play the alias and/ or binding game.
> Various ideas have been put forth for simplifying and improving the
> robustness of this, from #wrap_method, alias_method_chain, as well
> as :pre, :post methods and my own cuts (albeit they go a bit further
> than just method wrapping). But occurs to me that these add
> complexities onto something that is already straightforward if we are
> willing to separate out all class concerns into modules. In other
> words instead of writing:
>
>   class X
>     def a; "a";  end
>   end
>
> write:
>
>   module Xa
>     def a; "a";  end
>   end
>
>   class X
>     include Xa
>   end
>
>   X.new.a  #=> "a"
>
> Then it's easy enough to overlay new behaviors:
>
>   module Xb
>     def a; "{"+super+"}";  end
>   end
>
>   class X
>     include Xb
>   end
>
>   X.new.a  #=> "{a}"
>
> Since that works so well, it occurs to me, why not make this the
> fundamental behavior of defining a class? In other words defining a
> class:
>
>   class X
>     def a; "a"; end
>   end
>
> could be equivalent to writing:
>
>   class X
>     include( Module.new{
>         def a; "a";  end
>     } )
>   end
>
> So there would always be a module involved in the definition of a
> class. And classes become simply containers of modules.
>
> T.
>
>
>