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Subject: Re: [boost] AlRangeExandrescu?
From: David Abrahams (dave_at_[hidden])
Date: 2009-07-28 18:16:17

on Tue Jul 28 2009, Neil Groves <> wrote:

> On Tue, Jul 28, 2009 at 9:25 PM, Andrei Alexandrescu <
> andrei_at_[hidden]> wrote:
>> Neil Groves wrote:
>>> I'm unsure what the Boost::RangeEx::iterator would be, and why we need
>>> such
>>> a thing.
>> Without having perused either Boost::Range or Boost::RangeEx, I think it's
>> customary to give named access to the underlying iterator type, just like
>> containers e.g. define iterator, size_type etc.
> Oh I see, we have something that achieves a similar goal, I think. We have
> the iterator type in a typedef within the range classes currently. The
> prefered manner to write a range algorithm though uses a type generator
> class: range_iterator< Rng >::type to allow access to the underlying
> iterator type. This allows extension and support for ranges non-intrusively
> so we have been able to add range algorithm support seamlessly to even MFC
> containers, for example. Does this appear optimal to you, or can we improve
> this arrangement?

That's basic state-of-the-art for C++03 generic libraries, so I doubt
there's much room for improvement within the current language. Well,
you could use the concept check library to define the associated types
within the concept classes; that's a slightly more forward-looking

Dave Abrahams
BoostPro Computing

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