From: Mathieu Bouchard <matju@...>
Date: 2001-08-12T13:40:52+09:00
Subject: [ruby-talk:19570] Re: Perl/Python/Ruby common backend  (Parrot, can Ruby play too?)


On Wed, 8 Aug 2001, Piers Cawley wrote:
> Mathieu Bouchard <matju@sympatico.ca> writes:

> > > You can 'sort of' do mixins with perl
> > >     BEGIN {
> > >         do "Module.pm" || die "Couldn't load module";
> > >     }
> > > just make sure that 'Module.pm' doesn't have a package declaration. As
> > > you can no doubt see from its cumbersome syntax, mixins are not
> > > generally used within perl.
> > That's way too sort-of to be called "mixins" 
> Maybe I'm completely misunderstanding what ruby's mixins are. From my
> reading of the pickaxe book, mixins are simply chunks of code that get
> compiled into the class that includes them. Which is what the perl
> code above does too.

mixins are way closer to multiple inheritance than that.

> Well... one could argue that in most cases where Perl does MI, the
> 'extra' parent classes are used in the same way as ruby mixins, and

You can't do real ruby mixins in Perl, at least not the way I use them.

> Hang on, I'm confused. You seem to imply that mixins can inherit from
> other mixins. Or is it that Ruby mixins only get compiled once (if you
> try that in Perl you end up having *enormous* problems with SUPER:: at
> the moment...)

mixins inherit from other mixins statically through their inheritance list
(think @ISA), *and* dynamically, because the 'statically' part is just 
a special case in a larger scheme of making 'super' work as the
_continuation_ of the method-lookup.

matju