Re: [boost] zip iterator over containers of unequal sizes

From: David Abrahams (dave_at_[hidden])
Date: 2005-07-26 10:37:13

Leo Goodstadt <leo.goodstadt_at_[hidden]> writes:

> The zip iterator documentation says:
> "The zip iterator provides the ability to parallel-iterate over several
> controlled sequences simultaneously. ... 
> Moving the zip iterator moves all the iterators in parallel."
>
> What is not specified is what happens when the several different
> sequences are of unequal size. 
> At the moment, everything just blows up.
>
> python zip, if I remember correctly, just stops at the end of the
> shortest sequence in the tuple. (python map works differently).
> This seems a sensible thing to do.

Doesn't seem like such a great idea to me.  It forces you to pay at
each iteration of a loop when you could pay once to ensure that your
ending zip iterator is formed from the correct position in each
sequence.  In my opinion the zip_iterator documentation should be
improved (quite a lot) to make the requirements more explicit.

-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com