/*=============================================================================
    Copyright (c) 2001-2011 Joel de Guzman
    Copyright (c) 2007 Tobias Schwinger

    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_SEQUENCE_BASE_04182005_0737)
#define FUSION_SEQUENCE_BASE_04182005_0737

#include <boost/config.hpp>
#include <boost/fusion/support/config.hpp>
#include <boost/mpl/begin_end_fwd.hpp>

namespace boost {
namespace fusion {
namespace detail {
struct from_sequence_convertible_type
{};
}

template <typename Sequence>
struct sequence_base
{
    BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
    Sequence const&
    derived() const BOOST_NOEXCEPT
    {
        return static_cast<Sequence const&>(*this);
    }

    BOOST_CXX14_CONSTEXPR BOOST_FUSION_GPU_ENABLED
    Sequence&
    derived() BOOST_NOEXCEPT
    {
        return static_cast<Sequence&>(*this);
    }

    BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
    operator detail::from_sequence_convertible_type() const BOOST_NOEXCEPT
    {
        return detail::from_sequence_convertible_type();
    }
};

struct fusion_sequence_tag;
}
}

namespace boost {
namespace mpl {
// Deliberately break mpl::begin, so it doesn't lie that a Fusion sequence
// is not an MPL sequence by returning mpl::void_.
// In other words: Fusion Sequences are always MPL Sequences, but they can
// be incompletely defined.
template<> struct begin_impl< boost::fusion::fusion_sequence_tag >;
}
}

#endif
