[Python-Dev] issue with itertools leads the crash

[Chris Angelico]

On Wed, Apr 9, 2014 at 2:40 AM, Eric Snow <ericsnowcurrently at gmail.com> wrote:
> On Apr 8, 2014 10:31 AM, "MRAB" <python at mrabarnett.plus.com> wrote:
>> If the RHS yields too few, e.g. 3, you'll get:
>>
>> ValueError: attempt to assign sequence of size 3 to extended slice of size 4
>>
>> If it yields too many, e.g. 10, you'll get:
>>
>> ValueError: attempt to assign sequence of size 10 to extended slice of size 4
> [snip]
>> The fix would be to complain of raise StopIteration doesn't occur after
>> N+1 yields, where N is the number of values needed by the LHS.
>
> Perhaps N+2 would be better:
>
>   raise RuntimeError('{} is right out'.format(n+2))

It would be nice to have a simple notation that fetches what it needs
and ignores any extras.

a, b, c, * = x.split("-")

Bomb if there aren't two hyphens in x, but if there are more, just
take the first three and ignore the rest. Would work with infinite
iterators quite happily.

ChrisA