Boost C++ Libraries

boost/fusion/support/detail/access.hpp

/*=============================================================================
    Copyright (c) 2001-2006 Joel de Guzman

    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)
==============================================================================*/
#if !defined(FUSION_ACCESS_04182005_0737)
#define FUSION_ACCESS_04182005_0737

#include <boost/mpl/eval_if.hpp>
#include <boost/mpl/identity.hpp>
#include <boost/type_traits/add_const.hpp>
#include <boost/type_traits/add_reference.hpp>
#include <boost/type_traits/is_reference.hpp>
#include <boost/type_traits/remove_cv.hpp>

namespace boost { namespace fusion { namespace detail
{
    template <typename T>
    struct ref_result
    {
        typedef typename add_reference<typename T::type>::type type;
    };

    template <typename T>
    struct cref_result
    {
        typedef typename 
            add_reference<
                typename add_const<typename T::type>::type
            >::type 
        type;
    };

    template <typename T>
    struct non_ref_parameter
    {
        typedef typename boost::remove_cv<T>::type const& type;
    };

    template <typename T>
    struct call_param
    {
        typedef typename 
            mpl::eval_if<
                is_reference<T>
              , mpl::identity<T>
              , non_ref_parameter<T>
            >::type
        type;
    };
}}}

#endif