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Date: Sun, 25 Dec 2011 23:32:41 +1100
Subject: Re: Adding an interface to existing classes
From: Chris Angelico <rosuav@gmail.com>
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Xref: x330-a1.tempe.blueboxinc.net comp.lang.python:17883

On Sun, Dec 25, 2011 at 11:10 PM, Steven D'Aprano
<steve+comp.lang.python@pearwood.info> wrote:
> class Point: =A0# An abstract class.
> =A0 =A0def intersect(self, other):
> =A0 =A0 =A0 =A0blah; blah; blah
> =A0 =A0 =A0 =A0return Point(x, y) =A0# No, wrong, bad!!! Don't do this.
>
> Instead:
>
> =A0 =A0 =A0 =A0return self.__class__(x, y) =A0# 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