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Re: Delegation in Python

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Date Sun, 25 Jan 2015 11:28:34 +1100
Subject Re: Delegation in Python
From Chris Angelico <rosuav@gmail.com>
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On Sun, Jan 25, 2015 at 11:18 AM, Brian Gladman <noone@nowhere.net> wrote:
> 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?

Hmm. The key here is that you want more than just delegation; you want
to transform every return value. That's not going to be easy. It would
be easiest and cleanest to skip the whole thing, and have a separate
function for what you're doing here - not a method, a stand-alone
function.

def is_integer(fr):
    return fr.numerator % fr.denominator == 0

Next best would be the monkey-patching option. Delegation with
transformation is a lot of effort for what you want.

ChrisA

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Thread

Delegation in Python Brian Gladman <noone@nowhere.net> - 2015-01-24 22:57 +0000
  Re: Delegation in Python Chris Angelico <rosuav@gmail.com> - 2015-01-25 10:22 +1100
    Re: Delegation in Python Brian Gladman <noone@nowhere.net> - 2015-01-24 23:38 +0000
      Re: Delegation in Python Chris Angelico <rosuav@gmail.com> - 2015-01-25 10:43 +1100
        Re: Delegation in Python Brian Gladman <noone@nowhere.net> - 2015-01-25 00:18 +0000
          Re: Delegation in Python Chris Angelico <rosuav@gmail.com> - 2015-01-25 11:28 +1100
            Re: Delegation in Python Brian Gladman <noone@nowhere.net> - 2015-01-25 07:49 +0000
              Re: Delegation in Python Chris Angelico <rosuav@gmail.com> - 2015-01-25 19:07 +1100
      Re: Delegation in Python Gary Herron <gherron@digipen.edu> - 2015-01-24 15:47 -0800
        Re: Delegation in Python Brian Gladman <noone@nowhere.net> - 2015-01-24 23:58 +0000
  Re: Delegation in Python Gary Herron <gherron@digipen.edu> - 2015-01-24 15:41 -0800
    Re: Delegation in Python Brian Gladman <noone@nowhere.net> - 2015-01-24 23:52 +0000
  Re: Delegation in Python Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-01-24 23:59 +0000
  Re: Delegation in Python Chris Angelico <rosuav@gmail.com> - 2015-01-25 11:07 +1100
  Re: Delegation in Python Terry Reedy <tjreedy@udel.edu> - 2015-01-24 20:31 -0500
    Re: Delegation in Python Brian Gladman <noone@nowhere.net> - 2015-01-25 07:43 +0000

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