Re: [boost] [patch] first_iterator, second_iterator?

Subject: Re: [boost] [patch] first_iterator, second_iterator?
From: Gabriel Redner (gredner_at_[hidden])
Date: 2010-01-07 21:50:09

On Thu, Jan 7, 2010 at 4:56 PM, Daniel Colascione
<daniel_at_[hidden]> wrote:
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> On 1/7/10 6:25 AM, Mathias Gaunard wrote:
>> Daniel Colascione wrote:
>>> Iterating over the first and second elements of a collection of pairs is
>>> a pretty common problem. Would it be possible to get something like the
>>> following into boost?
>>
>> Isn't that a trivial application of transform_iterator?
>>
>
> Sure, it can be implemented via transform_iterator too. And it is a
> trivial application. But it serves two purposes:
>
> 1) provides commonly-needed functionality with only a little additional code
>
> 2) provides examples for library users
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FWIW, I've implemented exactly this tool in the codebase at work,
using the transform_iterator technique.  I've also written an
analogous tool which extracts a particular element from each element
in a collection of boost::tuples.  I'd have been happy to see either
or both as part of boost, or at least as examples in the iterator
library.

-Gabe