Re: [Boost-users] [Range & c++0x Lambdas] Can this be done?

Subject: Re: [Boost-users] [Range & c++0x Lambdas] Can this be done?
From: Jeffrey Lee Hellrung, Jr. (jeffrey.hellrung_at_[hidden])
Date: 2012-11-28 23:20:13

On Wed, Nov 28, 2012 at 7:35 PM, Nathan Crookston <
nathan.crookston_at_[hidden]> wrote:
[...]

> With or without a change to result_of, I believe there's value in allowing
> the user to explicitly specify the result_type of a callable object passed
> to transformed.  Ticket #7748[1] contains a patch which permits that.
>
> Thanks,
> Nate
>
> [1] https://svn.boost.org/trac/boost/ticket/7748
>

I would think a preferable (in the sense of separation of concerns,
modularity, what-have-you) solution would be an addition to
Boost.Functional (or whatever) that basically wraps a callable object and
forces its result_type to be some specified template parameter. E.g.,

template< class F, class R >
struct result_binder
{
  F f;
  typedef R result_type;
  template< class... T >
  result_type operator()(T&&... x) const
  { return f(std::forward<T>(x)...); }
};

template< class R, class F >
result_binder<F,R>
bind_result(F&& f)
{ return result_binder<F,R>{std::forward<F>(f)}; }

[or something like that]

- Jeff