is_sequence.hpp

来自「Boost provides free peer-reviewed portab」· HPP 代码 · 共 66 行

/*=============================================================================
    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_IS_SEQUENCE_05052005_1002)
#define FUSION_IS_SEQUENCE_05052005_1002

#include <boost/type_traits/is_base_of.hpp>
#include <boost/fusion/support/sequence_base.hpp>
#include <boost/fusion/support/tag_of.hpp>
#include <boost/mpl/is_sequence.hpp>
#include <boost/mpl/or.hpp>
#include <boost/mpl/bool.hpp>

namespace boost { namespace fusion
{
    // Special tags:
    struct non_fusion_tag;
    struct boost_tuple_tag; // boost::tuples::tuple tag
    struct array_tag; // boost::array tag
    struct mpl_sequence_tag; // mpl sequence tag
    struct std_pair_tag; // std::pair tag

    namespace extension
    {
        template <typename T>
        struct is_sequence_impl
        {
            template <typename Sequence>
            struct apply : is_base_of<sequence_root, Sequence> {};
        };

        template <>
        struct is_sequence_impl<non_fusion_tag>
        {
            template <typename T>
            struct apply : mpl::false_ {};
        };

        template <>
        struct is_sequence_impl<boost_tuple_tag>;

        template <>
        struct is_sequence_impl<array_tag>;

        template <>
        struct is_sequence_impl<mpl_sequence_tag>;

        template <>
        struct is_sequence_impl<std_pair_tag>;
    }

    namespace traits
    {
        template <typename T>
        struct is_sequence
            : extension::is_sequence_impl<typename detail::tag_of<T>::type>::
                template apply<T>
        {};
    }
}}

#endif