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To: python-list@python.org
From: Terry Reedy <tjreedy@udel.edu>
Subject: Re: (test) ? a:b
Date: Sun, 26 Oct 2014 17:12:46 -0400
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Xref: csiph.com comp.lang.python:79728

On 10/26/2014 12:15 AM, Steven D'Aprano wrote:
> Ben Finney wrote:
>
>> Steven D'Aprano <steve+comp.lang.python@pearwood.info> writes:
>>
>>> I suspect that Guido and the core developers disagree with you, since=

>>> they had the opportunity to fix that in Python 3 and didn't.
>>
>> That doesn't follow; there are numerous warts in Python 2 that were no=
t
>> fixed in Python 3. As I understand it, the preservation of bool=E2=80=93=
int
>> equality has more to do with preserving backward compatibility.
>
> On reviewing PEP 285, I think it is safe to say that Guido *explicitly*=

> wants bools to be ints, not just for backwards compatibility:
>
>      4) Should we strive to eliminate non-Boolean operations on bools
>         in the future, through suitable warnings, so that for example
>         True+1 would eventually (in Python 3000) be illegal?
>
>      =3D> No.
>
>         There's a small but vocal minority that would prefer to see
>         "textbook" bools that don't support arithmetic operations at
>         all, but most reviewers agree with me that bools should always
>         allow arithmetic operations.
>
> http://legacy.python.org/dev/peps/pep-0285/

Thank you for digging this up.  I was one of the 'most reviewers'.

Even though filter now returns an iterator, so that one can write

sum(1 for _ in filter(None, iterable_of_bools))

without creating an unneeded itermediate list, I still prefer

sum(iterable_of_bools)

for efficiency not only for the machine but also for me writing and readi=
ng.

[snip of fine disquisition on the subject to which I have nothing to add]=


--=20
Terry Jan Reedy