[Python-Dev] Re: Re: accumulator display syntax

Guido van Rossum guido at python.org
Tue Oct 21 14:09:33 EDT 2003


> On Tuesday 21 October 2003 09:27 am, Greg Ewing wrote:
>    ...
> > But maybe some other keyword could be added to ease any
> > syntactic problems, such as "all" or "every":
> >
> >   sum(all x*x for x in xlist)
> >   sum(every x*x for x in xlist)
> >
> > The presence of the extra keyword would then distinguish
> > an iterator comprehension from the innards of a list
> > comprehension.
> 
> Heh, you ARE a volcano of cool syntactic ideas these days, Greg.
> 
> As between them, to me 'all' sort of connotes 'all at once' while
> 'every' connotes 'one by one' (so would a third possibility, 'each');
> so 'all' is the one I like least.
> 
> Besides accumulators &c we should also think of normal loops:
> 
> for a in all x*x for x in xlist: ...
> 
> for a in every x*x for x in xlist: ...
> 
> for a in each x*x for x in xlist: ...
> 
> Of these three, 'every' looks best to me, personally.
> 
> 
> Alex

I'd rather reserver these keywords for conditions using quantifiers,
like in ABC.

--Guido van Rossum (home page: http://www.python.org/~guido/)



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