From: Ross Bamford <rosco@...>
Date: 2005-11-27T09:32:27+09:00
Subject: Re: Nubish questions about syntax and gems

On Sat, 26 Nov 2005 21:44:00 -0000, David A. Black <dblack@wobblini.net>  
wrote:

> What you've got basically is:
>
>    class A
>      @@foo = "A's class variable foo"
>    end
>    @@foo = "Object's class variable foo"
>    class B
>      @@foo = "B's class variable foo"
>    end
>
> Since B is a subclass of Object, setting B's @@foo also sets Object's
> @@foo.  The reason A's @@foo (when you see it via the instance eval)
> does not change is that if you create a subclass's class variable
> *first*, and then the superclass's (in this case, A and Object,
> respectively), they are separate:
>
> irb(main):002:0> class A; end; class B < A; @@foo = 1; end; class A;
> @@foo = 2; puts @@foo; end
> 2
> => nil
> irb(main):003:0> class B; puts @@foo; end
> 1
>David

That's pretty subtle. Definitely one for the notebook.

Cheers,

-- 
Ross Bamford - rosco@roscopeco.remove.co.uk