Caleb Hattingh a écrit : > Peter > > To my mind, this kind of setup (interface class, or abstact class
are two different things. >) is > more usually used in static languages True. >to benefit polymorphism This is a good reason to use an interface in Java. C++ has no notion of 'interface', so you have to use abstract classes to achieve the same result. > - but > python is dynamically typed, so in which situations would this setup be > useful in a python program? Abstract classes ? When you want to factor out common implementation in a base class and force derived class to implement specific parts. One common use case is the template method (aka "hollywood", aka "don't call us, we'll call you") pattern. > You see, I expected your post to say that > it wouldn't even be necessary, but you didn't :) Implementation inheritance is never "necessary". Nor are OO, modularity, structured programming, and human-readable programming languages !-) It's a fact that inheritence being "only" (err... should I say "mostly" ?) an implementation mechanism in dynamic languages, class hierarchies tends to be much more flat. But this doesn't mean that abstract base classes are useless. > I have spent a little effort training myself not to bother setting up > class hierarchies like this in python I had this pattern too. -- http://mail.python.org/mailman/listinfo/python-list
