/*=============================================================================

    Copyright (c) 2005 Joel de Guzman

    Copyright (c) 2005 Eric Niebler



    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_CONS_07172005_0843)

#define FUSION_CONS_07172005_0843



#include <boost/fusion/support/detail/access.hpp>

#include <boost/fusion/sequence/intrinsic/begin.hpp>

#include <boost/fusion/sequence/intrinsic/end.hpp>

#include <boost/fusion/iterator/next.hpp>

#include <boost/fusion/iterator/deref.hpp>

#include <boost/fusion/container/list/cons_iterator.hpp>

#include <boost/fusion/container/list/detail/begin_impl.hpp>

#include <boost/fusion/container/list/detail/end_impl.hpp>

#include <boost/fusion/container/list/detail/at_impl.hpp>

#include <boost/fusion/container/list/detail/value_at_impl.hpp>

#include <boost/fusion/container/list/detail/empty_impl.hpp>

#include <boost/type_traits/is_convertible.hpp>

#include <boost/utility/enable_if.hpp>

#include <boost/fusion/support/sequence_base.hpp>

#include <boost/mpl/int.hpp>

#include <boost/mpl/bool.hpp>

#include <boost/mpl/or.hpp>



namespace boost { namespace fusion

{

    struct void_;

    struct cons_tag;

    struct forward_traversal_tag;

    struct fusion_sequence_tag;



    struct nil : sequence_base<nil>

    {

        typedef mpl::int_<0> size;

        typedef cons_tag fusion_tag;

        typedef fusion_sequence_tag tag; // this gets picked up by MPL

        typedef mpl::false_ is_view;

        typedef forward_traversal_tag category;

        typedef void_ car_type;

        typedef void_ cdr_type;



        nil() {}



        template <typename Iterator>

        nil(Iterator const& iter, mpl::true_ /*this_is_an_iterator*/)

        {}



        template <typename Iterator>

        void assign_from_iter(Iterator const& iter)

        {

        }

    };



    template <typename Car, typename Cdr = nil>

    struct cons : sequence_base<cons<Car, Cdr> >

    {

        typedef mpl::int_<Cdr::size::value+1> size;

        typedef cons_tag fusion_tag;

        typedef fusion_sequence_tag tag; // this gets picked up by MPL

        typedef mpl::false_ is_view;

        typedef forward_traversal_tag category;

        typedef Car car_type;

        typedef Cdr cdr_type;



        cons()

            : car(), cdr() {}



        explicit cons(typename detail::call_param<Car>::type car)

            : car(car), cdr() {}



        cons(

            typename detail::call_param<Car>::type car

          , typename detail::call_param<Cdr>::type cdr)

            : car(car), cdr(cdr) {}

        

        template <typename Car2, typename Cdr2>

        cons(cons<Car2, Cdr2> const& rhs)

            : car(rhs.car), cdr(rhs.cdr) {}



        cons(cons const& rhs)

            : car(rhs.car), cdr(rhs.cdr) {}



        template <typename Sequence>

        cons(

            Sequence const& seq

          , typename disable_if<

                mpl::or_<

                    is_convertible<Sequence, cons> // use copy ctor instead

                  , is_convertible<Sequence, Car>  // use copy to car instead

                > 

            >::type* dummy = 0

        )

            : car(*fusion::begin(seq))

            , cdr(fusion::next(fusion::begin(seq)), mpl::true_()) {}



        template <typename Iterator>

        cons(Iterator const& iter, mpl::true_ /*this_is_an_iterator*/)

            : car(*iter)

            , cdr(fusion::next(iter), mpl::true_()) {}



        template <typename Car2, typename Cdr2>

        cons& operator=(cons<Car2, Cdr2> const& rhs)

        {

            car = rhs.car;

            cdr = rhs.cdr;

            return *this;

        }



        cons& operator=(cons const& rhs)

        {

            car = rhs.car;

            cdr = rhs.cdr;

            return *this;

        }



        template <typename Sequence>

        typename disable_if<is_convertible<Sequence, Car>, cons&>::type

        operator=(Sequence const& seq)

        {

            typedef typename result_of::begin<Sequence const>::type Iterator;

            Iterator iter = fusion::begin(seq);

            this->assign_from_iter(iter);

            return *this;

        }



        template <typename Iterator>

        void assign_from_iter(Iterator const& iter)

        {

            car = *iter;

            cdr.assign_from_iter(fusion::next(iter));

        }



        car_type car;

        cdr_type cdr;

    };

}}



#endif



