[Python-Dev] Semantics of __int__(), __index__()

Chris Angelico rosuav at gmail.com
Thu Apr 4 17:01:53 CEST 2013


On Fri, Apr 5, 2013 at 1:59 AM, Guido van Rossum <guido at python.org> wrote:
> On Thu, Apr 4, 2013 at 7:47 AM, Chris Angelico <rosuav at gmail.com> wrote:
>> Is there any argument that I can pass to Foo() to get back a Bar()?
>> Would anyone expect there to be one? Sure, I could override __new__ to
>> do stupid things, but in terms of logical expectations, I'd expect
>> that Foo(x) will return a Foo object, not a Bar object. Why should int
>> be any different? What have I missed here?
>
>
> A class can define a __new__ method that returns a different object. E.g.
> (python 3):
>

Right, I'm aware it's possible. But who would expect it of a class?

ChrisA


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