On Fri, 26 Feb 2010 12:40:22 +1300 Greg Ewing <greg.ewing@canterbury.ac.nz> wrote:
spir wrote:
But the analog does not apply to filter-only list comps: [x in numbers if x%2==1] # SyntaxError
If you were allowed to say that, you should also be able to say
[x in numbers] but this already has a meaning as an ordinary list constructor.
Yes, that's precisely the semantics it should have (consistent with my view that <item in collection> is the core of a comprehension), since there is neither a mapping, nore a filter.
Requiring the word 'for' to appear in an LC ensures that there is never any ambiguity.
Yes, but the issue is rather with (x in numbers) beeing a test. (--> ambiguity of "in")
However, it might be possible to phrase it another way, e.g.
[x from numbers if x%2==1]
Wow, I like that. Better term than "in", in my opinion. (and solves the ambiguity of "in", but then consistency require to change "for x in numbers", which has about -1% chances to happen, I guess ;-) Denis -- ________________________________ la vita e estrany spir.wikidot.com