[boost] Re: typeof: lvalue preserving

From: Arkadiy Vertleyb (vertleyb_at_[hidden])
Date: 2004-07-22 08:08:45

Giovanni Bajo wrote:

>Arkadiy Vertleyb wrote:
>
> > One more addition to the typeof library is a macro, that, unlike
> > BOOST_TYPEOF(), which removes top-level consts and references,
> > attempts to be closer to the decltype, by preserving lvalue-ness of
> > its argument:
> >
> > BOOST_TYPEOF_PRESERVE_LVALUE(expr)
> >
> > I do admit that the name is quite clumzy :(
>
> BOOST_DECLTYPE?

Well, unfortunately, it's not exactly decltype :(

In particular:

int i;
const int ci = 0;

                decltype     BOOST_TYPEOF_PRESERVE_LVALUE
                --------     ----------------------------
i               int              int&
ci             const int     const int&

etc.

It is calculated by binding a T& to the expression. If it can't be bound the
type is the same as one returned by BOOST_TYPEOF. If it can, it's either
reference or const reference, depending on the constness of T.

Any suggestions how to make it closer to the real decltype?

Arkadiy