On 02/12/2015 06:57 PM, Steven D'Aprano wrote: > On Thu, Feb 12, 2015 at 06:14:22PM -0800, Ethan Furman wrote: >> On 02/12/2015 05:46 PM, MRAB wrote: >>> On 2015-02-13 00:55, Guido van Rossum wrote: > >>>> Actually, the problem is that the base class (e.g. int) doesn't know how >>>> to construct an instance of the subclass -- there is no reason (in >>>> general) why the signature of a subclass constructor should match the >>>> base class constructor, and it often doesn't. >>>> >>>> So this is pretty much a no-go. It's not unique to Python -- it's a >>>> basic issue with OO. >>>> >>> Really? >> >> What I was asking about, and Guido responded to, was not having to >> specifically override __add__, __mul__, __sub__, and >> all the others; if we do override them then there is no problem. > > I think you have misunderstood MRAB's comment. My interpretation is > that MRAB is suggesting that methods in the base classes should use > type(self) rather than hard-coding their own type.
That makes more sense, thanks. -- ~Ethan~
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