"Paul McGuire" <[EMAIL PROTECTED]> wrote: > In Python, this would look like: > > class Parrot: > def __eq__(self, other): > return self is other or self.plumage() == other.plumage() > def __ne__(self, other): > return self is not other and self.plumage() != other.plumage() > def __lt__(self, other): > return self is not other and self.plumage() < other.plumage() > def __gt__(self, other): > return self is not other and self.plumage() > other.plumage() > def __le__(self, other): > return self is not other and self.plumage() <= other.plumage() > def __ge__(self, other): > return self is not other and self.plumage() >= other.plumage() > > and George's metaclass would have similar changes. > > On the other hand, I haven't seen this idiom in any Python code that > I've read, and I wonder if this was just a coding fad of the time.
It is a perfectly reasonable short-cut for those types where you know an object is equal to itself, but that isn't always the case. e.g. floating point NaN values are not equal to themselves, and a list of numbers might contain a NaN which would mean the list wouldn't be equal to itself. Also note that for the __le__, __ge__ cases you got the shortcut test the wrong way round. -- http://mail.python.org/mailman/listinfo/python-list
