From: djd15@...
Date: 2003-08-12T22:02:00+09:00
Subject: Re: newbie mixin questions



----- Original Message -----
From: Robert Klemme <bob.news@gmx.net>
Date: Tuesday, August 12, 2003 7:23 am
Subject: Re: newbie mixin questions

> 
> "Michael Garriss" <mgarriss@earthlink.net> schrieb im Newsbeitrag
> news:3F37F45B.8080002@earthlink.net...
> > dblack@superlink.net wrote:
> >
> > >One other technique that might be relevant is Module#included, 
> which> >as I understand it is essentially a new name for 
> append_features.  (Is
> > >that accurate?)  Here's a 1.8.0 example:
> > >
> > >  module M
> > >    def self.included(c)
> > >      def c.something
> > >        puts "I'm a class method!"
> > >      end
> > >    super
> > >    end
> > >
> > >    def another
> > >      puts "I'm an instance method!"
> > >    end
> > >  end
> > >
> > >The inclusion now operates, with fairly clear separation, on 
> both the
> > >class and the instances:
> > >
> > >  class A; include M; end
> > >
> > >  A.something
> > >  A.new.another
> > >
> > >
> > >David
> > >
> > >
> > >
> >
> > That's what I needed.  Thanks!
> 
> But: you now have multiple something methods with the same definition.
> That's ugly.  I'd prefer the approach to extend a class with M as 
> shown in
> the other postings:
> 
> > [matz:]
> >
> > class Bar
> >   Bar.extend(Foo)
> > end
> 
> [Gavin]:
> Alternatively
> 
>  class Bar
>    extend Foo
>  end

Or as a third alternative, I imagine you could do:

module MyClassMethods
   def class_foo
   end
   def class_bar
   end
end

module MyModule
   def included(c)
      c.extend(MyClassMethods)
      super
   end

   def instance_foo
   end
   def instance_bar
   end
end

That way it looks like you get both instance and
class methods from one module, and you share the
class methods (if I take your objection correctly).

Unless I'm confused and that doesn't work.

- Dan