[Python-ideas] [Python-Dev] Inclusive Range
python at mrabarnett.plus.com
Tue Oct 5 21:43:29 CEST 2010
On 05/10/2010 20:23, spir wrote:
> On Tue, 05 Oct 2010 13:45:56 +0200
> Boris Borcic<bborcic at gmail.com> wrote:
>> Nick Coghlan wrote:
>>> [...] Being able to say things like
>>> "10:00"<= x< '12:00", 10.0<= x< 12.0, "a"<= x< "n" are much
>>> clearer than trying to specify their closed range equivalents.
>> makes one wonder about syntax like :
>> for 10<= x< 20 :
>> Mh, I suppose with rich comparisons special methods, it's possible to turn
>> chained comparisons into range factories without introducing new syntax.
>> Something more like
>> for x in (10<= step(1)< 20) :
> About notation, even if loved right-hand-half-open intervals, I would wonder about [a,b] noting it. I guess 99.9% of programmers and novices (even purely amateur) have learnt about intervals at school in math courses. Both notations I know of use [a,b] for closed intervals, while half-open ones are noted either [a,b[ or [a,b). Thus, for me, the present C/python/etc notation is at best misleading.
> So, what about a hypothetical language using directly math *unambiguous* notation, thus also letting programmers chose their preferred semantics (without fooling others)? End of war?
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Dijkstra came to his conclusion after seeing the results of students
using the programming language Mesa, which does support all 4 forms of
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