On 24/01/2015 23:43, Chris Angelico wrote: > On Sun, Jan 25, 2015 at 10:38 AM, Brian Gladman <no...@nowhere.net> wrote: >> On 24/01/2015 23:22, Chris Angelico wrote: >>> class RF(Fraction): >>> def is_integer(self): >>> return self.numerator % self.denominator == 0 >> >> Thanks for your help on this. I must admit that nowhere in a lot of >> searching did I find that delegation is achieved by doing nothing! > > Hehe :) If you want a technical look at it, what you have is the > fundamental nature of subclassing: you derive from another class, and > your class is identical to that with certain exceptions (in your case, > an additional method). Python's way of handling that is called the > Method Resolution Order or MRO, and you can find info on it on the > web, eg: > > http://python-history.blogspot.com/2010/06/method-resolution-order.html
Thanks for the further background. Is there a way of doing delegation rather than sub-classing? That is, can I create a class (say RF) that passes some of its methods to Fraction for implementation but always returns an RF? Brian -- https://mail.python.org/mailman/listinfo/python-list
