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Subject: Re: [boost] Standard library Technical Report 2 proposals for Boost libraries
From: Dave Abrahams (dave_at_[hidden])
Date: 2011-12-17 16:59:17

on Fri Dec 16 2011, "Jeffrey Lee Hellrung, Jr." <> wrote:

> On Thu, Dec 15, 2011 at 4:28 AM, Dave Abrahams <dave_at_[hidden]> wrote:
>> > On Thu, Dec 8, 2011 at 11:44 AM, Olaf van der Spek <ml_at_[hidden]>
>> wrote:
>> >
>> >> Are there any plans to propose Boost Iterator for TR2?
>> I have no plans, and it really wouldn't be appropriate in its current
>> form. It needs a thorough going-over and probably a few design changes
>> before it would be ready for another attempt at standardization. The
>> standards proposals were determined to be not fully-baked enough when we
>> submitted them the last time.
> I wonder, Dave, when you get a chance, if you can elaborate on this.

There are a number of issues I can think of just off the top of my
head. The rest are probably evident from looking at Trac tickets:

* The concepts are wrong, in an abstract sense. They're too granular
  and not based on the needs of real algorithms. C++11 either got or was
  about-to-get-before-concepts-were-pulled new iterator concepts that
  should be used

* There's an adaptability hook that Robert Ramey has wanted for years
  and I think it should be implemented

* C++11 features should be exploited in any new design, especially if
  it's going to be proposed for TR2

* I think maybe we don't yet understand how to specify a component as
  flexible and default-heavy as iterator_facade at a level of rigor
  that's appropriate for the standard. It may be that the defaults
  should be computed much more simply than they are.


Dave Abrahams
BoostPro Computing

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