[Python-3000] Iterators for dict keys, values, and items == annoying :)

[Barry Warsaw]

On Fri, 2006-03-24 at 07:26 -0800, Guido van Rossum wrote:
> On 3/24/06, Barry Warsaw <barry at python.org> wrote:
> > On Thu, 2006-03-23 at 17:06 -0800, Guido van Rossum wrote:
> >
> > > The pattern with the 'empty' flag is only needed when due to API
> > > constraints you have only got an iterator.
> >
> > Which can happen quite often actually.  Perhaps making the original
> > object available as an attribute of the iterator can help in those
> > situations though.
> 
> It can't work, at least not in general. How do you do this if the
> iterator is a generator? Or an infinite sequence? Or a filter? It
> can't be made part of the iterator protocol. You can design your own
> extension of the iterator protocol, but then it wouldn't accept
> arbitrary iterators any more.

Yes, absolutely true.  I wasn't really proposing a change to the generic
iterator protocol, just suggestion something "one" could do if "one"
needed that functionality (although an agreed upon convention would make
it somewhat more general).

-Barry

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