Re: [boost] [Iterator] Adaptors for accessing keys/values in associative containers

From: Giovanni Piero Deretta (gpderetta_at_[hidden])
Date: 2007-08-10 08:05:49

> >BTW, I think that boost.bimap already provides them.
> I'd say that's a good reason to provide equivilent functionality for
> std::(multi)map and std::tr1::unordered_(multi)map.
>

Boost.bimap provides the first and second function objects. They will
work (when used with transform iterators) with all map-like objects.

> >Also function object wrappers for boost.tuple get<N> would really be useful.
> There's already a free function (boost::tuples::get<N>) that would
> work here (it is an actual function, not a function object, so the
> usual optimization issues are present), but it only works on tuples,
> not on std::pair - so it won't work with std::(multi)map and
> std::tr1::unordered_(multi)map.

It is very hard to use overloaded functions with boost.bind or lambda,
or as parameters to
transform iterators. This is why I explicitly said function object.
About get<N> not working
with pairs, fusion at_c works just fine for pairs, tuples and all
fusion sequences.

gpd