[Python-Dev] Single- vs. Multi-pass iterability

[Barry A. Warsaw]

>>>>> "AK" == Andrew Koenig <ark@research.att.com> writes:

    Barry> Would it be useful to add to the interator "interface" a
    Barry> method which would retrieve the original iterable object?

    AK> What if there isn't one?

    Barry> The method would return None.

    AK> But then you can't rely on it.  That is, if you want to write
    AK> code that depends on the ability to retrieve the original
    AK> iterable, you have to give up the ability for that code to
    AK> work on generators, for example.

    AK> I'm not saying it's not a useful thing to have; I'm just
    AK> saying it might not be as useful as it appears at first.

I'm not sure it's even useful at all, e.g. I've never had a use for
it.  But if you have code that depends on the ability to retrieve the
original iterable, and you have iterators for which there /is no/
original iterable, it doesn't matter how you spell it, you're going to
have to special case around that fact.

-Barry