// Copyright Alexander Nasonov 2004
//
// Use, modification and distribution are subject to 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)
//
// See http://www.boost.org/libs/mpl for documentation.

#ifndef BOOST_MPL_EMPTY_SEQUENCE_HPP_INCLUDED
#define BOOST_MPL_EMPTY_SEQUENCE_HPP_INCLUDED

#include <boost/mpl/clear_fwd.hpp>
#include <boost/mpl/iterator_tag.hpp>

namespace boost { namespace mpl {

namespace aux {

struct empty_sequence_tag {};

struct empty_sequence_iter
{
    typedef forward_iterator_tag category;
};

}

struct empty_sequence
{
    typedef aux::empty_sequence_iter begin;
    typedef aux::empty_sequence_iter end;
    typedef aux::empty_sequence_tag  tag;
};

template<>
struct clear_traits<aux::empty_sequence_tag>
{
    template<typename EmptySequence>
    struct algorithm
    {
        typedef empty_sequence type;
    };
};

}}

#endif // #ifndef BOOST_MPL_EMPTY_SEQUENCE_HPP_INCLUDED