From: ara.t.howard@...
Date: 2006-11-08T13:23:28+09:00
Subject: Re: Can't bind a singleton method to a subclass?

On Wed, 8 Nov 2006 dblack@wobblini.net wrote:

> I think it's not so much that you're unbinding it *from* B, as that you're
> grabbing it *through* B.  So, by the time you unbind it, it doesn't "know"
> that you got it that way; it's just a Method object, and it allows itself to
> be unbound.

yeah.  at first i thought that, but:

     harp:~ > cat a.rb
     class A
       def self.class_method() 42 end
     end
     class B < A; end

     p A.method(:class_method)
     p B.method(:class_method)


     harp:~ > ruby a.rb
     #<Method: A.class_method>
     #<Method: B(A).class_method>

so it seems like the method is aware that it's receiver is B.  but i take your
point.

> I'd say that's a side-effect of the fact that A's singleton
> methods can be got at via B at all.

yes.  put another way, and something i was be-moaning several years ago, is
this:

     harp:~ > cat a.rb
     class A
       SINGLETON_CLASS = class << self
         self
       end
     end
     class B < A
       SINGLETON_CLASS = class << self
         self
       end
     end

     p B::SINGLETON_CLASS.ancestors

     harp:~ > ruby a.rb
     [Class, Module, Object, Kernel]

singleton classes should respect inheritence.

regards.

-a
-- 
my religion is very simple.  my religion is kindness. -- the dalai lama