Re: [boost] Boost.Range questions

From: David Abrahams (dave_at_[hidden])
Date: 2005-06-17 12:45:09

Oliver Kullmann <O.Kullmann_at_[hidden]> writes:

> On Fri, Jun 17, 2005 at 10:27:53AM -0400, David Abrahams wrote:
>> "Thorsten Ottosen" <nesotto_at_[hidden]> writes:
>> 
>> Not really; especially if you show the "as-if" implementation of
>> boost::begin.  But more importantly, as far as I can tell from the
>> code, that *is* the actual requirement!  Otherwise, standard
>> containers don't satisfy the concept.  It doesn't matter how strange
>> it seems if the alternative is inaccurate.
>> 
>> 
>
> I don't think that the requirement should be
>
>                     boost::begin(v);
>
> since functions cannot be partially specialised, and only the
> overload mechanism together with ADL is available to use a
> user-defined begin-function. In cases like this I regard
> the requirement
>
>                     using boost::begin;
>                     begin(v);
>
> as the correct one:
>
>  - now standard containers fulfil the requirement;
>  - and used-defined versions of begin are taken into
>    account.

boost::begin is defined to look up a user-defined function via ADL.
This was extensively discussed on the mailing list.  I'm not saying
one is a better approach than another, just that you're coming in late
on an issue that's been considered.

My post is not about what the requirement ought to be; it's about how
to document the requirement that is already there in the code.

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