From: dblack@...
Date: 2006-06-17T06:28:51+09:00
Subject: Re: Why the lack of mixing-in support for Class methods?

Hi--

On Fri, 16 Jun 2006, Yukihiro Matsumoto wrote:

> Hi,
>
> In message "Re: Why the lack of mixing-in support for Class methods?"
>    on Fri, 16 Jun 2006 18:56:23 +0900, dblack@wobblini.net writes:
>
> |>  class C
> |>    include M
> |>  end
> |>  M.a = 42
> |>  p M.a # => 42
> |
> |Will this happen if the module is included in another module?  If so,
> |I'm wondering whether a more generic name, without "class" in it,
> |could be used instead of "class_extension".
>
> That's where I am wondering.  Using the Daniel's code:
>
>  module M
>    class_extension do
>      def foo
>      end
>    end
>  end
>  module M2
>    include M
>  end
>  class C
>    include M2
>  end
>
>  M.foo   # => NoMethodError
>  M2.foo  # => Error? (should it affect modules?)

Yes, I think so.

>  C.foo   # => Error? (should class_extension be propagated?)

I think not.  The call to class_extension in M registers a policy on
the part of M.  The policy affects M2, but it should not be shared by
M2.

> If 'class_extension' affects modules as well, do you think of any
> more generic name, in place of "class" extension?

Sean O'H. mentioned "extension", which I think is as good as it will
get.  (I'm still not a fan of this whole thing.)


David

-- 
David A. Black (dblack@wobblini.net)
Ruby Power and Light, LLC (http://www.rubypowerandlight.com)

See what the readers are saying about "Ruby for Rails"!
http://www.rubypowerandlight.com/quotes