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

[Ka-Ping Yee]

On Tue, 16 Jul 2002, Guido van Rossum wrote:
> Yup.  I regret this too.  We should have had a built-in next(x) which
> calls x.__next__().

Ah!  I think one of the hang-ups i (we? the BOF?) got stuck on was
that users of iterators would sometimes call next() directly, and
so it wouldn't do to call it __next__.  But it's clear to me now that
a built-in next() is exactly the right answer, by analogy to the
built-in repr() and method __repr__.

> But yes, it's too late to change now.

Sigh.  Well, in the hope that it makes the change a little easier
to swallow, i'll say now that if the protocol is fixed in some
future version of Python, i'll volunteer to update the standard
library to the new protocol.  I guess when Python 3 comes around,
there's going to me some sort of migration helper tool, and that
tool can check for classes that have __iter__ and next, and
suggest changing the name to __next__.


-- ?!ng