From: Stefano Crocco <stefano.crocco@...>
Date: 2008-02-07T00:54:41+09:00
Subject: Re: Pattern for "include"ing class methods?

Alle Wednesday 06 February 2008, Clifford Heath ha scritto:
> ara howard wrote:
> > module M
> >     module ClassMethods
> >     end
> >
> >     module InstanceMethods
> >     end
> >
> >     def M.inherited other
> >       other.send :extend, ClassMethods
> >       other.send :include InstanceMethods
> >    end
> > end
>
> Interesting idea, but it doesn't seem to work, and I don't see
> how it could (though I've mangled it into something different
> that does work).
>
> How and when should module M get used, and how does inherited
> get called?
>
> My look at the Ruby doc says the "inherited" callback only works
> on classes, not on modules...? Is this a 1.9 thing? If I change
> M to a class, then of course I can't use it as the argument to
> include or extend :-).
>
> What I *did* get to work was to add a method to class Module that
> does the include and extend. Which I guess I knew I could do anyhow...
>
> Clifford Heath.

I think you need M.included, not M.inherited:

module M

  module ClassMethods
    def m1
      puts "m1"
    end
  end

  module InstanceMethods
    def m2
      puts "m2"
    end
  end

  def self.included other
    other.send :include, InstanceMethods
    other.send :extend, ClassMethods
  end
end

class C
  include M
end

C.m1
C.new.m2

Stefano

Stefano