PEP 285: Adding a bool type

[Alex Martelli]

Aahz wrote:

> In article <KM_p8.41075$pT1.1129125 at news1.tin.it>,
> Alex Martelli  <aleax at aleax.it> wrote:
>>
>>0 is (2.2 is still present, not yet past) the canonical way to spell
>>untruth: it's what 'not', 'is', 'in', comparisons, and all standard
>>library iswhatever's return -- including operator.truth, of course.
> 
> Just to throw in a datapoint, I generally use None to indicate falsehood.

...and you can presumably continue to indulge in this quirk, if you so
choose, after 285 passes.  'return 0' is obviously faster (a LOAD_CONST
opcode, rather than a LOAD_GLOBAL for either 'return False' or explicit
'return None', where the latter always has to check globals() first
and then proceed to the built-ins), but just as obviously the difference
is so minute as not to matter -- a matter of 10% slowdown on my
machine for 100,000 calls to a function whose body is just return None,
versus one whose body is just return 0 (0.45 vs 0.41 secs for 100,000
calls including timing overhead, python -O, time.clock).  An _implicit_
return None (fall-off-the-end) would be just as fast as return 0, but
I would consider it seriously obfuscated (while 'return None' strikes me
as only moderately so -- just because of the difference wrt what all
of the builtin and library equivalents).


Alex