[boost] Re: [multi_index] ANN: Post-review version available

From: Joaquin M Lopez Munoz (joaquin_at_[hidden])
Date: 2004-04-30 09:09:34

Pavel Vozenilek <pavel_vozenilek <at> hotmail.com> writes:

> 
> "Joaquín Mª López Muñoz" <joaquin <at> tid.es> wrote:
> 
> >  The complete list of changes after requests from
> > the reviewers can be consulted at:
> >
> >
> http://groups.yahoo.com/group/boost/files/multi_index_postreview_notes.html
> >
> >From the document:
> 
> ...
> Functional changes:
> No duplicate tags are allowed, either inside a tag or globally in an
> instantiation of multi_index_container. A BOOST_STATIC_CHECK is triggered if
> this condition is violated.
> ...
> Requests that have not been implemented:
> Some reviewers were in favor of supressing the multi-tag functionality.
> Others, like Jeremy Maitin-Shepard, found this feature useful. I took the
> least-work option and kept it.
> 
> ???

I guess your ???ing means that you interpret these
two statements as contradictory. They are not. The first
indicates that things like the following are banned:

multi_index_container<
  employee,
  indexed_by<
    ordered_unique<tag<hello>,...>,
    ordered_non_unique<tag<hello>,...> //hello already used!
  >
>

multi_index_container<
  employee,
  indexed_by<
    ordered_unique<tag<hello,bye,hello>,...> // intra-index duplication!
  >
>

While the second statement refers to the fact
that you can assign more than one tag to the same index,
as in

multi_index_container<
  employee,
  indexed_by<
    ordered_unique<tag<hello,bye>,...> // fine
  >
>

(which is how it was before the review)

Is this what you're puzzled about?

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo