kj <no.em...@please.post> wrote: > >Suppose that I want to write a subclass C of base classes A and B. >What considerations should go into choosing the ordering of A and >B in C's base class list? >... >...it is difficult for me to see a strong compelling reason for picking >an ordering over another. But may be just ignorance on my part. > >How should one go about deciding the ordering of base classes?
In general, it is uncommon to have a class that derives from multiple classes that all provide major functionality. That quickly gets confusing, which is one reason Java doesn't allow multiple inheritance. Now, it is very common for a class to derive from one class primarily, with other classes providing a few additional features. That's the "mix-in" concept. In that case, you'd list the "major" ancestor first, with the mix-ins after, so the mix-ins can modify the behavior. class BlueSpanishListBox( ListBox, ColorBlueMixIn, SpanishMixIn ): ... Reading it, a BlueSpanishListBox is-a ListBox that happens to have a few additional features. -- Tim Roberts, t...@probo.com Providenza & Boekelheide, Inc. -- http://mail.python.org/mailman/listinfo/python-list