Lame wrapper for `hana::partial` to use `std::ref`s

PartialRef.hpp

//
// Copyright Jason Rice 2016
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//
#ifndef NBDL_DETAILS_PARTIAL_REF_HPP
#define NBDL_DETAILS_PARTIAL_REF_HPP

#include<boost/hana.hpp>
#include<functional>

namespace nbdl {
namespace details {

namespace hana = boost::hana;

struct RefWrap
{
  template<typename T>
  constexpr auto operator()(T const& t) const
  {
    return std::cref(t);
  }
};
constexpr RefWrap ref_wrap{};

struct RefUnwrap
{
  template<typename T>
  constexpr auto operator()(std::reference_wrapper<T> const& t) const
  {
    return t.get();
  }
};
constexpr RefUnwrap ref_unwrap{};

struct PartialRef
{
  template<typename F, typename... Args>
  constexpr auto operator()(F const& f, Args const& ...args) const
  {
    return hana::on(hana::partial(f ^hana::on^ ref_unwrap, std::cref(args)...), ref_wrap);
  }
};
constexpr PartialRef partial_ref{};

struct ReversePartialRef
{
  template<typename F, typename... Args>
  constexpr auto operator()(F const& f, Args const& ...args) const
  {
    return hana::on(hana::reverse_partial(f ^hana::on^ ref_unwrap, std::cref(args)...), ref_wrap);
  }
};
constexpr ReversePartialRef reverse_partial_ref{};

}//details
}//nbdl

#endif