On Fri, Aug 29, 2008 at 6:22 AM, Phillip J. Eby <pje@telecommunity.com> wrote:
You're right, let's abolish inheritance, too, because then you might have to read more than one class to see what's happening.
You are joking, but I actually took this idea quite seriously. Once (four years ago or so) I did implement an object system from scratch in Scheme, completely without inheritance, to see how far it would go. It didn't go far, of course (nor I did expect it to go very far) but at least I learned exactly what (single) inheritance was good for. OTOH, for what concerns multiple inheritance, I am still not convinced it is really worth it. I mean, the MRO is beautiful, elegant and all that on paper, but on real-life code things as different, especially from the side of the users of frameworks heavily based on inheritance.
Naturally, if you can design a system to use delegates instead of class hierarchy to represent a chain of responsibility, it might well be an improvement. But there are tradeoffs, and no matter what you are going to end up coding chains of responsibility.
Agreed, it is all about tradeoffs. We have a different opinion on what a good tradeoff is in this case, but that's fine. I guess it depends on personal experience and the kind of code one has to work with. For instance I never had to integrated different frameworks using different metaclasses in my daily work, so I don't see a very strong case for classy_class over class decorators, but I could change my mind in the future, who knows? Anyway, It would be nice to have a good simple *real life* use case of cooperative inheritance not involving metaclasses, suitable for a beginners' tutorial about super, but I haven't found one yet :-( M.S.