From: Daniel Waite <rabbitblue@...>
Date: 2008-05-02T12:35:42+09:00
Subject: Re: DSL - class-level methods that affect instances

David A. Black wrote:
> I'd say: don't think of it as any more of a barrier than exists
> between any other two objects.

That helps, actually. Viscerally, for now, but I'm sure the fullness of 
the stance will sink in with time.

> (I know that sounds kind of doctrinaire, but I like to lay it on thick
> since it usually takes some doing to chip away at the presumptive
> class/instance special relationship :-)

I love saturated opinions. (David West all the way!) I'm re-reading your 
book right now starting from chapter 5, and yes, I can already tell I've 
lost a forgotten a lot of my understanding of how Ruby works. (I suppose 
you could argue I never understood it if I forgot...?)

> module Translator
>    attr_reader :translations
> 
>    def translate(target, actions)
>      @translations ||= []
>      @translations.push("Translating #{target} to #{actions[:to]}")
>    end
> end
> 
> class C
>    extend Translator
> 
>    def translations
>      self.class.translations
>    end
> 
>    translate "this", :to => "that"
> end
> 
> p C.new.translations   # ["Translating this to that"]

Works beautifully. Amazing. I thought I was going to end up with some 
monolithic structure like ActiveRecord. ;)

@Ken:

Your solution works equally well! I like that yours is class-based so I 
don't have to call extend in the body of each inheriting class (of which 
there will be quite a few).

I'm not worried about tertiary inheritance; I don't plan on needing it. 
(Famous last words, right?)

Thank you both, Ken and David, very much!
-- 
Posted via http://www.ruby-forum.com/.