less.hpp

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/*=============================================================================
    Copyright (c) 1999-2003 Jaakko Jarvi
    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_LESS_05052005_1141)
#define FUSION_LESS_05052005_1141

#include <boost/mpl/bool.hpp>
#include <boost/fusion/iterator/deref.hpp>
#include <boost/fusion/iterator/next.hpp>
#include <boost/fusion/iterator/equal_to.hpp>

namespace boost { namespace fusion { namespace detail
{
    template <typename Seq1, typename Seq2>
    struct sequence_less
    {
        typedef typename result_of::end<Seq1>::type end1_type;
        typedef typename result_of::end<Seq2>::type end2_type;

        template <typename I1, typename I2>
        static bool
        call(I1 const&, I2 const&, mpl::true_)
        {
            return false;
        }

        template <typename I1, typename I2>
        static bool
        call(I1 const& a, I2 const& b, mpl::false_)
        {
            return *a < *b
                || !(*b < *a)
                && call(fusion::next(a), fusion::next(b));
        }

        template <typename I1, typename I2>
        static bool
        call(I1 const& a, I2 const& b)
        {
            typename result_of::equal_to<I1, end1_type>::type eq;
            return call(a, b, eq);
        }
    };
}}}

#endif