Boost C++ Libraries

boost/fusion/adapted/struct/extension.hpp

/*=============================================================================
    Copyright (c) 2001-2007 Joel de Guzman
    Copyright (c) 2005-2006 Dan Marsden

    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_STRUCT_EXTENSION_APRIL_2_2007_1008AM)
#define FUSION_STRUCT_EXTENSION_APRIL_2_2007_1008AM

#include <boost/type_traits/add_const.hpp>

namespace boost { namespace fusion
{
    struct fusion_sequence_tag;

    namespace extension
    {
        template <typename Struct, int N>
        struct struct_member;

        template <typename Struct>
        struct struct_size;

        template <typename Struct, int N>
        struct struct_member<Struct const, N>
        {
            typedef typename
                add_const<typename struct_member<Struct, N>::type>::type
            type;

            static type&
            call(Struct const& struct_)
            {
                return struct_member<Struct, N>::call(
                    const_cast<Struct&>(struct_));
            }
        };

        template <typename Struct>
        struct struct_size<Struct const>
            : struct_size<Struct>
        {};

        struct no_such_member;

        template<typename Struct, typename Key>
        struct struct_assoc_member
        {
            typedef no_such_member type;
        };

        template<typename Struct, typename Key>
        struct struct_assoc_member<Struct const, Key>
        {
            typedef typename
                add_const<typename struct_assoc_member<Struct, Key>::type>::type
            type;

            static type&
            call(Struct const& struct_)
            {
                return struct_assoc_member<Struct, Key>::call(
                    const_cast<Struct&>(struct_));
            }
        };

    }
}}

#endif