who uses Python or Ruby, and for what?

[Fredrik Lundh]

Thomas Bellman wrote:
> > the iterator is the object that responds to __getitem__(lastindex+1),
> > not the loop variable itself.
>
> I think you should reread the section on the Iterator pattern in
> "Design Patterns".  To follow the iterator pattern, the iterator
> should be a *separate* object from the sequence that you are
> iterating over.

okay, I'll try again:

    the iterator is the object that responds to __getitem__(lastindex+1)
    by fetching the next element, not the loop variable itself.

(yeah, you can misinterpret that one too, but if you do that on
purpose, I'll come over and slap you with a huge big fish)

> FileInput is an iterator, yes.  As is the objects returned by
> xrange() (which iterates over the integral numbers) and the
> .xreadlines() method of file objects

and PIL's ImageSequence.Iterator, the DirectoryWalker sample I've
posted a couple of times, etc.  iterators are everywhere.

> The normal iteration API of old Python (old as in version 2.1 or
> older, of course :-), i.e putting a __getitem__() method on the
> collection type/class, *isn't* the Iterator pattern.

not by itself, no.  but you can use __getitem__ to implement
iterators, as we both know.  no disagreement here.

> "I don't think [that word] means what you
>  think it means."   -- The Princess Bride

if [that word] is "iterator", I don't think that quote is relevant
to this subthread ;-)

Cheers /F