From: "trans.  (T. Onoma)" <transami@...>
Date: 2005-01-18T15:08:50+09:00
Subject: Re: Fwd: [suby-ruby] Your all time desired fundemental Ruby mod

On Tuesday 18 January 2005 12:21 am, Martin DeMello wrote:
| "trans.  (T. Onoma)" <transami@runbox.com> wrote:
| > On Monday 17 January 2005 02:51 am, Martin DeMello wrote:
| > | I can think of at least one good us for the current @@ variables -
| > | subclassable GUI components that inherit hierarchy-shared look-and-feel
| > | properties from the parent class. What would be the elegant way to do
| > | this if @@ variables go per-class?
| >
| > You would have to do it via class instance vars. The problem with these
| > IMHO is still the intialization issue, as with modules (see
| > ruby-talk:121611, http://urltron.com/nd) Matz, do you think we can get
| > something in the way of remedying that? For me it's one of the biggest
| > sores in my code.
|
| How?
|
| class Button
|   @@background = BLUE
|
|   def repaint
|     @background = @@background
|     ...
|   end
| end
|
| class ImageButton < Button
| end
|
| Now if @@background were changed to Button.@background, how would
| repaint work in ImageButton?

BTW I personally like your style: Button.@background ;)

Try:

  class Button
    class < self
      def background
        @background ||= BLUE
      end
    end

    def repaint
      @background = self.class.background
      ...
    end
  end

  class ImageButton < Button
  end

That's the idea. Work for you?

T.