At 11:16 AM 11/22/2006 -0200, Gustavo Niemeyer wrote: >I've lost you here. As I understand interfaces, their most important >feature is indeed being a "comment in the form of code", and I hope >they continue to be that way.
What does it add to have to declare a class as being "Iterable", if it already implements __iter__? What does the notion of "Iterable" add to the execution *or* understanding of the code? If you say that it is because having "Iterable" is needed to distinguish different possible interpretations of the same method name(s), then why not just have method namespaces to begin with? "defop" is one way to do that, of course, but there could easily be others, like a "namespace" statement inside of classes that would contain the method definitions. I'd like to try to meet the needs, without assuming that "interfaces" are the right answer. Indeed, if interfaces are considered the answer, I want to know what the question is. :) Many years ago, I helped to create Zope's interface adaptation system, and I built PyProtocols as well, using interfaces quite extensively in PEAK. So, I am familiar with the presumed benefits of interfaces as well as their drawbacks -- especially their drawbacks. And chief amongst those drawbacks are complexity and duplication. In essence, interfaces turn libraries into "frameworks", but generic functions turn frameworks into libraries. I didn't really discover this until January of last year, though, when I did some experiments in replacing various PEAK interfaces with generic functions: http://dirtsimple.org/2005/01/like-acid-for-frameworks.html The experience of refactoring was what made me realize that generic functions weren't just for obscure fancy use cases like security rules and binary math operators. They *gutted* my interface-based code down to nothing -- hence my description of them as being "like acid for frameworks". _______________________________________________ Python-3000 mailing list Python-3000@python.org http://mail.python.org/mailman/listinfo/python-3000 Unsubscribe: http://mail.python.org/mailman/options/python-3000/archive%40mail-archive.com
