#ifndef BOOST_MPL_UNIQUE_HPP_INCLUDED

#define BOOST_MPL_UNIQUE_HPP_INCLUDED

// Copyright Aleksey Gurtovoy 2000-2004

// Copyright John R. Bandela 2000-2002

//

// 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)

//

// See http://www.boost.org/libs/mpl for documentation.

// $Source: /cvsroot/boost/boost/boost/mpl/unique.hpp,v $

// $Date: 2004/09/02 15:40:42 $

// $Revision: 1.7 $

#include <boost/mpl/fold.hpp>

#include <boost/mpl/reverse_fold.hpp>

#include <boost/mpl/eval_if.hpp>

#include <boost/mpl/and.hpp>

#include <boost/mpl/identity.hpp>

#include <boost/mpl/pair.hpp>

#include <boost/mpl/apply.hpp>

#include <boost/mpl/aux_/inserter_algorithm.hpp>

#include <boost/mpl/aux_/na.hpp>

#include <boost/mpl/aux_/na_spec.hpp>

#include <boost/mpl/aux_/lambda_spec.hpp>

namespace boost { namespace mpl {

namespace aux {

template< typename Predicate, typename Operation >

struct unique_op

{

    template< typename Pair, typename T > struct apply

    {

        typedef typename Pair::first seq_;

        typedef typename Pair::second prior_;

        typedef typename eval_if<

              and_< is_not_na<prior_>, apply2<Predicate,prior_,T> >

            , identity<seq_>

            , apply2<Operation,seq_,T>

            >::type new_seq_;

        typedef pair<new_seq_,T> type;

    };

};

template<

      typename Sequence

    , typename Predicate

    , typename Inserter

    >

struct unique_impl

    : first< typename fold<

          Sequence

        , pair< typename Inserter::state,na >

        , protect< aux::unique_op<Predicate,typename Inserter::operation> >

        >::type >

{

};

template<

      typename Sequence

    , typename Predicate

    , typename Inserter

    >

struct reverse_unique_impl

    : first< typename reverse_fold<

          Sequence

        , pair< typename Inserter::state,na >

        , protect< aux::unique_op<Predicate,typename Inserter::operation> >

        >::type >

{

};

} // namespace aux

BOOST_MPL_AUX_INSERTER_ALGORITHM_DEF(3, unique)

}}

#endif // BOOST_MPL_UNIQUE_HPP_INCLUDED