Re: [boost] [V1.46] [Iterator] Ask for release notes modification

Subject: Re: [boost] [V1.46] [Iterator] Ask for release notes modification
From: Mathias Gaunard (mathias.gaunard_at_[hidden])
Date: 2011-01-26 18:56:15

On 26/01/2011 18:51, Michel MORIN wrote:
> Dave Abrahams wrote:
>>> I see two alternatives:
>>> - either the fact that transform_iterator uses boost::result_of is
>>> removed from the release branch
>>> - or the release branch is fixed so that the feature is not buggy.
>>
>> Either one of those is OK with me.
>
> After digging into the transform_iterator's result_of problem further,
> I'm beginning to doubt the correctness of the documentation.
>
> I think that boost::result_of<UnaryFunction(Iterator::reference)>  (which is
> described in the documentation) is incorrect, and the correct one is
> boost::result_of<const UnaryFunction(Iterator::reference)>.
>
> This is because
> 1. The dereference operator of transform_iterator is a const member function.
> 2. So, in the dereference operator, UnaryFunction is treated as a const object.

After actually looking at the issue, I can confirm that is correct.
Good thing you spotted that (especially important for the decltype-based 
implementation of result_of).

> Hmm, what should we do?

I think the right thing to do is probably to make it use 
boost::result_of<const UnaryFunction(typename 
std::iterator_traits<Iterator>::reference)> on the trunk, fix the doc, 
check the tests still pass on all expected targets, then merge it to 
release unless the release manager disagrees.

I for one have been waiting for this feature for a long time, so I'd be 
glad to have it (and have it working!) in a release as soon as possible.