Re: [Boost-users] [multi index] combination with boos t::tuple

From: Joaquín Mª López Muñoz (joaquin_at_[hidden])
Date: 2007-01-23 10:53:37

Markus Werle ha escrito:

> Joaquín Mª López Muñoz <joaquin <at> tid.es> writes:
>
> > http://lists.boost.org/boost-users/2005/12/16087.php
>
> Thanks for the insight.
> If only boost::tuples::element<N,Tuple>::type was a documented feature ...

It's documented, although it's a little hard to find: go to "Advanced
features"
from Boost.Tuple docs main page.

> The inheritance problem you describe is another proof that inheritance
> should not be used to extend interfaces in generic code and that
> containment is the superior approach (religious flamewars or very
> good arguments against this appreciated).
>
> > And the other solution is to write a user-defined extractor as
> > explained in the aforementioned thread.
>
> Your post to comp.std.c++ had no response (thread "Pointer to member
> contravariance and template non-type arguments")
> Do you have any new insight on DR or not DR?

No, unfortunately nobody answered. My feeling is that this is a defect,
but I don't feel competent enough to file a DR withouht some prior
discussion with an expert in the standard.

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo