On 2007-02-14, Peter Otten <[EMAIL PROTECTED]> wrote: > Neil Cerutti wrote: > >> On 2007-02-13, Peter Otten <[EMAIL PROTECTED]> wrote: >>> Well, what problems ocurring with >>> >>> class A: pass >>> class B: pass >>> class C(A, B): pass >>> >>> could be avoided by writing >>> >>> class A: pass >>> class B(A): pass >>> class C(B): pass >>> >>> instead? >> >> With multiple inheritance, the choice of algorithm for Method >> Resolution Ordering isn't obvious or trivial. As I understand it, >> Python got it wrong for quite some time, allowing "bad" >> hierarchies to compile, i.e., classes for which the properties of >> local precedence ordering and monotonicity did not hold. >> >> URL:http://www.python.org/download/releases/2.3/mro/ > > Is it correct that as long as no classes occur twice in the > hierarchy no such ambiguities can arise?
As long as you forbid the diamond-shaped hierarchy, I think so. Of course, since all new-style classes inherit from 'object' you can't avoid it in practice, and a good algorithm for MRO had to be stolen from Dylan. ;) -- Neil Cerutti -- http://mail.python.org/mailman/listinfo/python-list
