[Python-ideas] PEP for issue2292, "Missing *-unpacking generalizations"

[Oscar Benjamin]

On 15 July 2013 12:08, Joshua Landau <joshua.landau.ws at gmail.com> wrote:
> On 15 July 2013 11:40, Oscar Benjamin <oscar.j.benjamin at gmail.com> wrote:
>>
>> Also this may be outside the scope of this PEP but since unpacking is
>> likely to be overhauled I'd like to put forward a previous suggestion
>> by Greg Ewing that there be a way to unpack some items from an
>> iterator without consuming the whole thing e.g.:
>>
>>     a, ... = iterable
>
> That's definitely outside of this PEP's scope ;). Also, I think you
> oversimplified your last version -- you still need a try-except
> AFAICT.

Where? The point is that next() raises StopIteration which is not an
acceptable type of Error. Leaking the StopIteration makes the function
not "generator-safe" i.e. if you call it from a generator the
StopIteration could terminate an outer loop. That's why I have the
try/except.

As long as

   a, ... = iterator

gives me a ValueError I'm happy to let the error propagate upwards.


Oscar