From: Rick DeNatale <rick.denatale@...>
Date: 2007-03-01T23:24:11+09:00
Subject: Re: How to get modules included by a class/module (not those from the superclasses)

On 2/28/07, Pit Capitain <pit@capitain.de> wrote:

> Including a module in a class that already has been included by one of
> its superclasses doesn't change the inheritance hierarchy:
>
>    module M
>    end
>
>    class P
>      include M
>    end
>
>    class C < P
>    end
>
>    p C.ancestors  # => [C, P, M, Object, Kernel]
>
>    class C
>      include M
>    end
>
>    p C.ancestors  # => [C, P, M, Object, Kernel]

This has changed in 1.9 (or at least as of a few months ago which was
the last time I built 1.9)

rick@frodo:~$ cat modtest.rb
module M
end

class P
  include M
end

class C < P
end

p C.ancestors

class C
  include M
end

p C.ancestors

rick@frodo:~$ ruby1.8 modtest.rb
[C, P, M, Object, Kernel]
[C, P, M, Object, Kernel]
rick@frodo:~$ ruby1.9 modtest.rb
[C, P, M, Object, Kernel, BasicObject]
[C, M, P, M, Object, Kernel, BasicObject]

I wrote about this back in October
http://talklikeaduck.denhaven2.com/articles/2006/10/09/a-subtle-change-to-mixin-semantics-in-ruby-1-9

-- 
Rick DeNatale

My blog on Ruby
http://talklikeaduck.denhaven2.com/