Martin v. Löwis schrieb:
> Ron Adam schrieb:
>> I think it's gets a bit awkward in some situations.
>>
>>
>> if bar->'__%s__' % attr < -42: print 'Hello World'
>>
>> if bar.['__%s__' % attr] > -42: print 'Hello World'
>>
>>
>> To me it's easier to parse the second one visually.
>
>
> Ah, precedence.
>
> It definitly should be a bracketed form, or else people
> always wonder what the precedence is, and add parenthesis
> anyway just to be on the safe side.
Indeed.
> BTW, which of these would be correct
>
> (a).[b]
Yes. (you can write (a).b today)
> (a.)[b]
No. (you can't write (a.)b today)
> a.[(b)]
Yes. (you can write a[(b)] today)
> a.([b])
No. (you can't write a([b]) today)
> a . [ b ]
Yes. (you can write a . b today)
In short, I'd just add a new form to Grammar's trailer:
trailer: '(' [arglist] ')' | '[' subscriptlist ']' | '.' attrtrailer
attrtrailer: '[' test ']' | NAME
This should be consistent and unsurprising.
> and what is the semantics of
>
> a.[42]
A TypeError, just as getattr(a, 42) would be.
I think I like the .[] form better, that being a +0 now.
Georg
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