On Jun 21, 2010, at 3:35 PM, J=F6rg W Mittag wrote:

> Eric MSP Veith wrote:
>> Modules are used for mixins. Is it possible -- and does it make sense =
at all=20
>> - -- to mixin a class into another class? I guess not?
>=20
> Actually, to add a bit to Brian's answer: it *is* possible and makes
> perfect sense. It's just not allowed in Ruby, but it *is* allowed in
> other languages.

Allowing classes to mixin other classes would change the class hierarchy =
from a tree to a directed acyclic graph.  As soon as you do that you =
have to figure out how to manage the method lookup process along =
multiple paths. I don't think there is any sort of consensus on how to =
do that (i.e. different languages take different approaches) and so=20
I'm not sure 'makes perfect sense' is an accurate characterization of =
the solution space for that problem.

Gary Wright=