From: Jim Driscoll <j@...>
Date: 2004-01-25T20:44:06+09:00
Subject: Re: Constant inheritance


On 25 Jan 2004, at 11:31, David Heinemeier Hansson wrote:

>> You could just use a class variable (e.g. @@x) instead, the downside 
>> being that it *would* be variable rather than constant.
>
> Right. The problem is that this really is a constant. The previous 
> example was a bit abstract. This should be more telling of my 
> intentions:
>

> ...but perhaps you're right. A class variable would probably suffice.
>

Okay, try this then (referring explicitly to the current namespace):

irb(main):001:0> class A
irb(main):002:1> X=2
irb(main):003:1> def X
irb(main):004:2> self.class.const_get :X
irb(main):005:2> end
irb(main):006:1> end
=> nil
irb(main):007:0> class B < A
irb(main):008:1> end
=> nil
irb(main):009:0> class C < A
irb(main):010:1> X=3
irb(main):011:1> end
=> 3
irb(main):012:0> A.new.X
=> 2
irb(main):013:0> C.new.X
=> 3
irb(main):014:0> B.new.X
=> 2
irb(main):015:0>


Jim