[Python-Dev] Mini-Pep: Simplifying the Integral ABC
ncoghlan at gmail.com
Thu Jun 5 15:20:40 CEST 2008
Terry Reedy wrote:
> "Raymond Hettinger" <python at rcn.com> wrote in message
> news:2745D7EB7C064B16A88E433588021756 at RaymondLaptop1...
> | From: "Guido van Rossum" <guido at python.org>
> | > Unless more folks actually say they agree I don't want to go forward
> | > with this. There was quite a bit of discussion about PEP 3141 and it
> | > was accepted; striking this much from it with virtually no discussion
> | > seems wrong to me.
> | Not sure how to generate more discussion. It seems self-evident
> | that an abc with lots of abstract methods is inherently less usable
> | and that bitwise operations go beyond the basic notion of "integeriness".
> On reading PEP3141 some months ago and again today, I thought and still do
> that all the methods that depend on a 2s-complement representation and
> implementation really belong to an implentation-defined subclass of
> Integral. But I am not sure of the purpose of the class and of including
> such concrete methods in an ABC, and so said nothing ;-).
I think it definitely makes sense to separate out the
number-as-sequence-of-bits operations from the main Integral ABC. This
would involve moving:
lshift, rshift, and, or, xor, invert (along with their reversed and
Note that this leaves the Integral ABC adding only __long__, __index__
and 3-argument __pow__ over and above the Rational ABC. If 3-argument
__pow__ goes (which appears likely), we're left with __long__ and __index__.
However, there's still a few additional public properties and methods
inherited from higher up in the numeric stack which most existing
integral types are unlikely to provide: .real, .imag, .conjugate().
Unlike the methods being relocated, however, these are absolutely
trivial for all non-complex numeric types.
Nick Coghlan | ncoghlan at gmail.com | Brisbane, Australia
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