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Groups > comp.lang.python > #17883

Re: Adding an interface to existing classes

References <8f345777-1ef7-46dc-b3fb-a0bea5ebf2c3@r16g2000prr.googlegroups.com> <22ea371a-f282-4d81-89f6-bc3229e2e8b1@a17g2000yqj.googlegroups.com> <4ef712c0$0$29973$c3e8da3$5496439d@news.astraweb.com>
Date 2011-12-25 23:32 +1100
Subject Re: Adding an interface to existing classes
From Chris Angelico <rosuav@gmail.com>
Newsgroups comp.lang.python
Message-ID <mailman.4063.1324816364.27778.python-list@python.org> (permalink)

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On Sun, Dec 25, 2011 at 11:10 PM, Steven D'Aprano
<steve+comp.lang.python@pearwood.info> wrote:
> class Point:  # An abstract class.
>    def intersect(self, other):
>        blah; blah; blah
>        return Point(x, y)  # No, wrong, bad!!! Don't do this.
>
> Instead:
>
>        return self.__class__(x, y)  # Better.

This would work if you were dealing with the intersection of two
points, but how do you use that sort of trick for different classes?

ChrisA

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Thread

Adding an interface to existing classes Spencer Pearson <speeze.pearson@gmail.com> - 2011-12-22 00:21 -0800
  Re: Adding an interface to existing classes Terry Reedy <tjreedy@udel.edu> - 2011-12-22 18:13 -0500
    Re: Adding an interface to existing classes Spencer Pearson <speeze.pearson@gmail.com> - 2011-12-24 15:49 -0800
      Re: Adding an interface to existing classes Terry Reedy <tjreedy@udel.edu> - 2011-12-24 20:58 -0500
        Re: Adding an interface to existing classes Spencer Pearson <speeze.pearson@gmail.com> - 2012-01-04 23:55 -0800
  Re: Adding an interface to existing classes Ian Kelly <ian.g.kelly@gmail.com> - 2011-12-24 18:16 -0700
    Re: Adding an interface to existing classes Spencer Pearson <speeze.pearson@gmail.com> - 2012-01-04 23:54 -0800
  Re: Adding an interface to existing classes Rick Johnson <rantingrickjohnson@gmail.com> - 2011-12-24 17:24 -0800
    Re: Adding an interface to existing classes Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-12-25 12:10 +0000
      Re: Adding an interface to existing classes Chris Angelico <rosuav@gmail.com> - 2011-12-25 23:32 +1100
        Re: Adding an interface to existing classes Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-12-25 13:27 +0000
          Re: Adding an interface to existing classes Chris Angelico <rosuav@gmail.com> - 2011-12-26 00:37 +1100
            Re: Adding an interface to existing classes Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-12-25 13:46 +0000
              Re: Adding an interface to existing classes Chris Angelico <rosuav@gmail.com> - 2011-12-26 00:55 +1100
              Re: Adding an interface to existing classes Spencer Pearson <speeze.pearson@gmail.com> - 2012-01-04 23:56 -0800

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