container/list/cons_iterator.hpp

0001 /*=============================================================================
0002     Copyright (c) 2001-2011 Joel de Guzman
0003     Copyright (c) 2005 Eric Niebler
0004
0005     Distributed under the Boost Software License, Version 1.0. (See accompanying
0006     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0007 ==============================================================================*/
0008 #if !defined(FUSION_CONS_ITERATOR_07172005_0849)
0009 #define FUSION_CONS_ITERATOR_07172005_0849
0010
0011 #include <boost/fusion/support/config.hpp>
0012 #include <boost/type_traits/add_const.hpp>
0013 #include <boost/fusion/support/iterator_base.hpp>
0014 #include <boost/fusion/container/list/detail/deref_impl.hpp>
0015 #include <boost/fusion/container/list/detail/next_impl.hpp>
0016 #include <boost/fusion/container/list/detail/value_of_impl.hpp>
0017 #include <boost/fusion/container/list/detail/equal_to_impl.hpp>
0018 #include <boost/fusion/container/list/list_fwd.hpp>
0019
0020 namespace boost { namespace fusion
0021 {
0022     struct nil_;
0023     struct cons_iterator_tag;
0024     struct forward_traversal_tag;
0025
0026     template <typename Cons>
0027     struct cons_iterator_identity;
0028
0029 #ifdef _MSC_VER
0030 #  pragma warning(push)
0031 #  pragma warning(disable: 4512) // assignment operator could not be generated.
0032 #endif
0033     template <typename Cons = nil_>
0034     struct cons_iterator : iterator_base<cons_iterator<Cons> >
0035     {
0036         typedef cons_iterator_tag fusion_tag;
0037         typedef forward_traversal_tag category;
0038         typedef Cons cons_type;
0039         typedef cons_iterator_identity<
0040             typename add_const<Cons>::type>
0041         identity;
0042
0043         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0044         explicit cons_iterator(cons_type& in_cons) BOOST_NOEXCEPT
0045             : cons(in_cons) {}
0046
0047         cons_type& cons;
0048     };
0049 #ifdef _MSC_VER
0050 #  pragma warning(pop)
0051 #endif
0052
0053     struct nil_iterator : iterator_base<nil_iterator>
0054     {
0055         typedef forward_traversal_tag category;
0056         typedef cons_iterator_tag fusion_tag;
0057         typedef nil_ cons_type;
0058         typedef cons_iterator_identity<
0059             add_const<nil_>::type>
0060         identity;
0061
0062         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0063         nil_iterator() BOOST_NOEXCEPT {}
0064         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0065         explicit nil_iterator(nil_ const&) BOOST_NOEXCEPT {}
0066     };
0067
0068     template <>
0069     struct cons_iterator<nil_> : nil_iterator
0070     {
0071         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0072         cons_iterator() BOOST_NOEXCEPT {}
0073         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0074         explicit cons_iterator(nil_ const&) BOOST_NOEXCEPT {}
0075     };
0076
0077     template <>
0078     struct cons_iterator<nil_ const> : nil_iterator
0079     {
0080         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0081         cons_iterator() BOOST_NOEXCEPT {}
0082         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0083         explicit cons_iterator(nil_ const&) BOOST_NOEXCEPT {}
0084     };
0085
0086     template <>
0087     struct cons_iterator<list<> > : nil_iterator
0088     {
0089         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0090         cons_iterator() BOOST_NOEXCEPT {}
0091         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0092         explicit cons_iterator(nil_ const&) BOOST_NOEXCEPT {}
0093     };
0094
0095     template <>
0096     struct cons_iterator<list<> const> : nil_iterator
0097     {
0098         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0099         cons_iterator() BOOST_NOEXCEPT {}
0100         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0101         explicit cons_iterator(nil_ const&) BOOST_NOEXCEPT {}
0102     };
0103 }}
0104
0105 #ifdef BOOST_FUSION_WORKAROUND_FOR_LWG_2408
0106 namespace std
0107 {
0108     template <typename Cons>
0109     struct iterator_traits< ::boost::fusion::cons_iterator<Cons> >
0110     { };
0111 }
0112 #endif
0113
0114 #endif