ts wrote:
...
> C> The more general question is if the "class localness" 
> C> should be extended to singleton class sub-classing (in 
> your example 
> C> the meta class of A and B respectively)
>                     ^^^^^^^^^^
> 
>  I don't know what is this :-))

metaA = class << A; self end

To give you another example of what I am trying to say lets say

class A
   def initialize
	@_test = "test"
   end
   def test
     @_var
   end
end

a =  A.new

p a.test # "test"

class << a
    def test
       @_var
   end
end

p a.test #  nil or "test" 

> 
> C> or if should be restricted to "regular" sub-classing.
> 
>  and a more general question is : instance variable must be 
> implemented for  class or only restricted for instance.


Now, I am not quite sure what you mean :-)

/Christoph