Re: [boost] Boost.Range questions

From: Oliver Kullmann (O.Kullmann_at_[hidden])
Date: 2005-06-17 10:24:08

On Fri, Jun 17, 2005 at 10:27:53AM -0400, David Abrahams wrote:
> "Thorsten Ottosen" <nesotto_at_[hidden]> writes:
> 
> > "David Abrahams" <dave_at_[hidden]> wrote in message 
> > news:ull5bnykl.fsf_at_boost-consulting.com...
> > |
> > | 1. What does it take to get support for standard containers as ranges?
> > |   According to what I can see in the documentation, the standard
> > |   containers don't satisfy the range concepts.  IOW,
> > |
> > |              begin(v)
> > |
> > |   isn't valid when v is a standard vector.
> > |
> > |   From what I can tell from browsing the implementation, the
> > |   requirement should be:
> > |
> > |               boost::begin(v)
> >
> > doesn't it seem strange that a concept requirement is bound to a certain 
> > namespace?
> 
> 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.

Oliver