Re: [boost] [reference_wrapper] add operator()(Args...) to reference_wrapper

Subject: Re: [boost] [reference_wrapper] add operator()(Args...) to reference_wrapper
From: Jeffrey Lee Hellrung, Jr. (jeffrey.hellrung_at_[hidden])
Date: 2012-05-10 14:21:27

On Thu, May 10, 2012 at 2:32 AM, Philipp Moeller <
philipp.moeller_at_[hidden]> wrote:

> "Jeffrey Lee Hellrung, Jr." <jeffrey.hellrung_at_[hidden]> writes:
>
> > On Wed, May 9, 2012 at 3:04 AM, Philipp Moeller <
> > philipp.moeller_at_[hidden]> wrote:
> >
> >> "Jeffrey Lee Hellrung, Jr." <jeffrey.hellrung_at_[hidden]> writes:
> >>
> >> > On Fri, Apr 20, 2012 at 5:03 AM, Philipp Moeller <
> >> > philipp.moeller_at_[hidden]> wrote:
> >> >
> >> >> Given that Boost now has perfect forwarding emulation through
> Boost.Move
> >> >> and a better result_of, would it be possible to enable
> reference_wrapper
> >> >> to forward the function call operator?
> >> >>
> >> >> The current behavior is somewhat surprising and makes a few of the
> most
> >> >> promising applications of reference_wrapper (reference wrap
> polymorphic
> >> >> boost::function objects) impossible with code that is no prepared to
> >> >> work with reference_wrapper. It would also be more consistent with
> >> >> reference_wrapper of the stdlib.
> >> >>
> >> >> I can file a corresponding bug report and add a patch, if there is
> >> >> interest.
> >> >>
> >> >
> >> > I think this would make a nice addition to the
> boost::reference_wrapper
> >> > interface.
> >> >
> >> > Isn't there a CRTP base class in Boost that aids in programming
> >> > nearly-perfect forwarding in C++03?
> >> >
> >>
> >> I couldn't find it and did it with PP.
> >>
> >> I've added this as ticket #6876 [1] for boost::bind. I'm unsure if this
> >> belongs there or to some other component and the maintainer of bind
> >> seems inactive. So I would be glad if someone else could have a look at
> >> that patch, it might need some tweaking (especially the macro names).
> >>
> >> Footnotes:
> >> [1]  https://svn.boost.org/trac/boost/ticket/6876
> >>
> >
> > I think this is what I was thinking of:
> >
> >
> http://www.boost.org/doc/libs/1_49_0/libs/functional/forward/doc/html/index.html
> >
>
> As far as I see this does not use or enable move semantics and has a
> higher compilation time. But I would surely prefer it over the current
> solution if those features could be added. Maybe it should also include
> a fully functional version if the necessary compiler features are
> available.
>

Actually, looking at this a second time, this isn't the CRTP base class I
was thinking of :/ This is mildly annoying that I can't find it...

In any case, yes, if the appropriate compiler features are present
(variadic templates and/or rvalue references), any solution should make use
of those.

- Jeff