Chris@16: ///////////////////////////////////////////////////////////////////////////////
Chris@16: // cons.hpp
Chris@16: //
Chris@16: //  Copyright 2008 Eric Niebler. Distributed under the Boost
Chris@16: //  Software License, Version 1.0. (See accompanying file
Chris@16: //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: #ifndef BOOST_XPRESSIVE_DETAIL_UTILITY_CONS_HPP_EAN_11_19_2005
Chris@16: #define BOOST_XPRESSIVE_DETAIL_UTILITY_CONS_HPP_EAN_11_19_2005
Chris@16: 
Chris@16: #include <boost/version.hpp>
Chris@16: 
Chris@16: #if BOOST_VERSION >= 103300
Chris@16: 
Chris@16: // In Boost 1.33+, we have a cons list in Fusion, so just include it.
Chris@16: 
Chris@16: # if BOOST_VERSION >= 103500
Chris@16: #  include <boost/fusion/include/cons.hpp> // Boost 1.35+ has Fusion2
Chris@16: # else
Chris@16: #  include <boost/spirit/fusion/sequence/cons.hpp> // Fusion1
Chris@16: # endif
Chris@16: 
Chris@16: #else
Chris@16: 
Chris@16: // For earlier versions of Boost, put the definition of cons here
Chris@16: # include <boost/call_traits.hpp>
Chris@16: # include <boost/mpl/if.hpp>
Chris@16: # include <boost/mpl/eval_if.hpp>
Chris@16: # include <boost/mpl/identity.hpp>
Chris@16: # include <boost/type_traits/is_const.hpp>
Chris@16: # include <boost/type_traits/add_const.hpp>
Chris@16: # include <boost/type_traits/add_reference.hpp>
Chris@16: # include <boost/spirit/fusion/detail/config.hpp>
Chris@16: # include <boost/spirit/fusion/detail/access.hpp>
Chris@16: # include <boost/spirit/fusion/iterator/next.hpp>
Chris@16: # include <boost/spirit/fusion/iterator/equal_to.hpp>
Chris@16: # include <boost/spirit/fusion/iterator/as_fusion_iterator.hpp>
Chris@16: # include <boost/spirit/fusion/iterator/detail/iterator_base.hpp>
Chris@16: # include <boost/spirit/fusion/sequence/begin.hpp>
Chris@16: # include <boost/spirit/fusion/sequence/end.hpp>
Chris@16: # include <boost/spirit/fusion/sequence/as_fusion_sequence.hpp>
Chris@16: # include <boost/spirit/fusion/sequence/detail/sequence_base.hpp>
Chris@16: 
Chris@16: namespace boost { namespace fusion
Chris@16: {
Chris@16:     struct nil;
Chris@16: 
Chris@16:     struct cons_tag;
Chris@16: 
Chris@16:     template <typename Car, typename Cdr>
Chris@16:     struct cons;
Chris@16: 
Chris@16:     struct cons_iterator_tag;
Chris@16: 
Chris@16:     template <typename Cons>
Chris@16:     struct cons_iterator;
Chris@16: 
Chris@16:     namespace cons_detail
Chris@16:     {
Chris@16:         template <typename Iterator>
Chris@16:         struct deref_traits_impl
Chris@16:         {
Chris@16:             typedef typename Iterator::cons_type cons_type;
Chris@16:             typedef typename cons_type::car_type value_type;
Chris@16: 
Chris@16:             typedef typename mpl::eval_if<
Chris@16:                 is_const<cons_type>
Chris@16:               , add_reference<typename add_const<value_type>::type>
Chris@16:               , add_reference<value_type> >::type
Chris@16:             type;
Chris@16: 
Chris@16:             static type
Chris@16:             call(Iterator const& i)
Chris@16:             {
Chris@16:                 return detail::ref(i.cons.car);
Chris@16:             }
Chris@16:         };
Chris@16: 
Chris@16:         template <typename Iterator>
Chris@16:         struct next_traits_impl
Chris@16:         {
Chris@16:             typedef typename Iterator::cons_type cons_type;
Chris@16:             typedef typename cons_type::cdr_type cdr_type;
Chris@16: 
Chris@16:             typedef cons_iterator<
Chris@16:                 typename mpl::eval_if<
Chris@16:                     is_const<cons_type>
Chris@16:                   , add_const<cdr_type>
Chris@16:                   , mpl::identity<cdr_type>
Chris@16:                 >::type>
Chris@16:             type;
Chris@16: 
Chris@16:             static type
Chris@16:             call(Iterator const& i)
Chris@16:             {
Chris@16:                 return type(detail::ref(i.cons.cdr));
Chris@16:             }
Chris@16:         };
Chris@16: 
Chris@16:         template <typename Iterator>
Chris@16:         struct value_traits_impl
Chris@16:         {
Chris@16:             typedef typename Iterator::cons_type cons_type;
Chris@16:             typedef typename cons_type::car_type type;
Chris@16:         };
Chris@16: 
Chris@16:         template <typename Cons>
Chris@16:         struct begin_traits_impl
Chris@16:         {
Chris@16:             typedef cons_iterator<Cons> type;
Chris@16: 
Chris@16:             static type
Chris@16:             call(Cons& t)
Chris@16:             {
Chris@16:                 return type(t);
Chris@16:             }
Chris@16:         };
Chris@16: 
Chris@16:         template <typename Cons>
Chris@16:         struct end_traits_impl
Chris@16:         {
Chris@16:             typedef cons_iterator<
Chris@16:                 typename mpl::if_<is_const<Cons>, nil const, nil>::type>
Chris@16:             type;
Chris@16: 
Chris@16:             static type
Chris@16:             call(Cons& t)
Chris@16:             {
Chris@16:                 FUSION_RETURN_DEFAULT_CONSTRUCTED;
Chris@16:             }
Chris@16:         };
Chris@16:     } // namespace cons_detail
Chris@16: 
Chris@16:     namespace meta
Chris@16:     {
Chris@16:         template <typename Tag>
Chris@16:         struct deref_impl;
Chris@16: 
Chris@16:         template <>
Chris@16:         struct deref_impl<cons_iterator_tag>
Chris@16:         {
Chris@16:             template <typename Iterator>
Chris@16:             struct apply : cons_detail::deref_traits_impl<Iterator> {};
Chris@16:         };
Chris@16: 
Chris@16:         template <typename Tag>
Chris@16:         struct next_impl;
Chris@16: 
Chris@16:         template <>
Chris@16:         struct next_impl<cons_iterator_tag>
Chris@16:         {
Chris@16:             template <typename Iterator>
Chris@16:             struct apply : cons_detail::next_traits_impl<Iterator> {};
Chris@16:         };
Chris@16: 
Chris@16:         template <typename Tag>
Chris@16:         struct value_impl;
Chris@16: 
Chris@16:         template <>
Chris@16:         struct value_impl<cons_iterator_tag>
Chris@16:         {
Chris@16:             template <typename Iterator>
Chris@16:             struct apply : cons_detail::value_traits_impl<Iterator> {};
Chris@16:         };
Chris@16: 
Chris@16:         template <typename Tag>
Chris@16:         struct begin_impl;
Chris@16: 
Chris@16:         template <>
Chris@16:         struct begin_impl<cons_tag>
Chris@16:         {
Chris@16:             template <typename Sequence>
Chris@16:             struct apply : cons_detail::begin_traits_impl<Sequence>
Chris@16:             {};
Chris@16:         };
Chris@16: 
Chris@16:         template <typename Tag>
Chris@16:         struct end_impl;
Chris@16: 
Chris@16:         template <>
Chris@16:         struct end_impl<cons_tag>
Chris@16:         {
Chris@16:             template <typename Sequence>
Chris@16:             struct apply : cons_detail::end_traits_impl<Sequence>
Chris@16:             {};
Chris@16:         };
Chris@16:     } // namespace meta
Chris@16: 
Chris@16:     template <typename Cons = nil>
Chris@16:     struct cons_iterator : iterator_base<cons_iterator<Cons> >
Chris@16:     {
Chris@16:         typedef cons_iterator_tag tag;
Chris@16:         typedef Cons cons_type;
Chris@16: 
Chris@16:         explicit cons_iterator(cons_type& cons_)
Chris@16:             : cons(cons_) {}
Chris@16: 
Chris@16:         cons_type& cons;
Chris@16:     };
Chris@16: 
Chris@16:     template <>
Chris@16:     struct cons_iterator<nil> : iterator_base<cons_iterator<nil> >
Chris@16:     {
Chris@16:         typedef cons_iterator_tag tag;
Chris@16:         typedef nil cons_type;
Chris@16:         cons_iterator() {}
Chris@16:         explicit cons_iterator(nil const&) {}
Chris@16:     };
Chris@16: 
Chris@16:     template <>
Chris@16:     struct cons_iterator<nil const> : iterator_base<cons_iterator<nil const> >
Chris@16:     {
Chris@16:         typedef cons_iterator_tag tag;
Chris@16:         typedef nil const cons_type;
Chris@16:         cons_iterator() {}
Chris@16:         explicit cons_iterator(nil const&) {}
Chris@16:     };
Chris@16: 
Chris@16:     struct nil : sequence_base<nil>
Chris@16:     {
Chris@16:         typedef cons_tag tag;
Chris@16:         typedef void_t car_type;
Chris@16:         typedef void_t cdr_type;
Chris@16:     };
Chris@16: 
Chris@16:     template <typename Car, typename Cdr = nil>
Chris@16:     struct cons : sequence_base<cons<Car,Cdr> >
Chris@16:     {
Chris@16:         typedef cons_tag tag;
Chris@16:         typedef typename call_traits<Car>::value_type car_type;
Chris@16:         typedef Cdr cdr_type;
Chris@16: 
Chris@16:         cons()
Chris@16:           : car(), cdr() {}
Chris@16: 
Chris@16:         explicit cons(
Chris@16:             typename call_traits<Car>::param_type car_
Chris@16:           , typename call_traits<Cdr>::param_type cdr_ = Cdr())
Chris@16:           : car(car_), cdr(cdr_) {}
Chris@16: 
Chris@16:         car_type car;
Chris@16:         cdr_type cdr;
Chris@16:     };
Chris@16: 
Chris@16:     template <typename Car>
Chris@16:     inline cons<Car>
Chris@16:     make_cons(Car const& car)
Chris@16:     {
Chris@16:         return cons<Car>(car);
Chris@16:     }
Chris@16: 
Chris@16:     template <typename Car, typename Cdr>
Chris@16:     inline cons<Car, Cdr>
Chris@16:     make_cons(Car const& car, Cdr const& cdr)
Chris@16:     {
Chris@16:         return cons<Car, Cdr>(car, cdr);
Chris@16:     }
Chris@16: }} // namespace boost::fusion
Chris@16: 
Chris@16: namespace boost { namespace mpl
Chris@16: {
Chris@16:     template <typename Tag>
Chris@16:     struct begin_impl;
Chris@16: 
Chris@16:     template <typename Tag>
Chris@16:     struct end_impl;
Chris@16: 
Chris@16:     template <>
Chris@16:     struct begin_impl<fusion::cons_tag>
Chris@16:       : fusion::meta::begin_impl<fusion::cons_tag>
Chris@16:     {
Chris@16:     };
Chris@16: 
Chris@16:     template <>
Chris@16:     struct end_impl<fusion::cons_tag>
Chris@16:       : fusion::meta::end_impl<fusion::cons_tag>
Chris@16:     {
Chris@16:     };
Chris@16: 
Chris@16: }} // namespace boost::mpl
Chris@16: 
Chris@16: #endif
Chris@16: 
Chris@16: // Before Boost v1.33.1, Fusion cons lists were not valid MPL sequences.
Chris@16: #if BOOST_VERSION < 103301
Chris@16: namespace boost { namespace mpl
Chris@16: {
Chris@16:     template<typename Iterator>
Chris@16:     struct next;
Chris@16: 
Chris@16:     template<typename Cons>
Chris@16:     struct next<fusion::cons_iterator<Cons> >
Chris@16:       : fusion::cons_detail::next_traits_impl<fusion::cons_iterator<Cons> >
Chris@16:     {
Chris@16:     };
Chris@16: 
Chris@16:     template<typename Iterator>
Chris@16:     struct deref;
Chris@16: 
Chris@16:     template<typename Cons>
Chris@16:     struct deref<fusion::cons_iterator<Cons> >
Chris@16:       : fusion::cons_detail::value_traits_impl<fusion::cons_iterator<Cons> >
Chris@16:     {
Chris@16:     };
Chris@16: 
Chris@16: }} // namespace boost::mpl
Chris@16: #endif
Chris@16: 
Chris@16: #endif