From: Robert Dober <robert.dober@...>
Date: 2008-08-28T00:54:45+09:00
Subject: Re: Difficult Inheritance Problem

On Wed, Aug 27, 2008 at 2:55 PM, David A. Black <dblack@rubypal.com> wrote:
> Hi --
>
> On Wed, 27 Aug 2008, Robert Dober wrote:
>
>> On Wed, Aug 27, 2008 at 1:37 PM, David A. Black <dblack@rubypal.com>
>> wrote:
>> Wow that is great, I would call them viral class variables!
>
> I think class variables are already viral :-)
Well they are unique, applying your pattern however the following holds

class X < Page
   @difference_mapping = 42
end

Y = Class::new( X )

Y.difference_mapping  => 42
*while*
Next.difference_mapping is still the hash.
-----------------------------------------------------

I meant with viral that the *new* values are propagated *only* down
the inheritance tree that is what OP wanted and I have to admit I did
not see immediately that your solution was correct in that regard.
When I realized how it was I found it quite amazing.

I should have said that self.inherited was viral.

Cheers
Robert