[Python-ideas] [Python-Dev] Inclusive Range
python at mrabarnett.plus.com
Tue Oct 5 21:41:46 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?
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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