list/detail/build_cons.hpp

0001 /*=============================================================================
0002     Copyright (c) 2001-2011 Joel de Guzman
0003
0004     Distributed under the Boost Software License, Version 1.0. (See accompanying
0005     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0006 ==============================================================================*/
0007 #if !defined(FUSION_BUILD_CONS_09232005_1222)
0008 #define FUSION_BUILD_CONS_09232005_1222
0009
0010 #include <boost/fusion/support/config.hpp>
0011 #include <boost/fusion/container/list/cons.hpp>
0012 #include <boost/fusion/iterator/equal_to.hpp>
0013 #include <boost/fusion/iterator/next.hpp>
0014 #include <boost/fusion/iterator/value_of.hpp>
0015 #include <boost/fusion/iterator/deref.hpp>
0016
0017 namespace boost { namespace fusion { namespace detail
0018 {
0019     template <
0020         typename First
0021       , typename Last
0022       , bool is_empty = result_of::equal_to<First, Last>::value>
0023     struct build_cons;
0024
0025     template <typename First, typename Last>
0026     struct build_cons<First, Last, true>
0027     {
0028         typedef nil_ type;
0029
0030         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0031         static nil_
0032         call(First const&, Last const&)
0033         {
0034             return nil_();
0035         }
0036     };
0037
0038     template <typename First, typename Last>
0039     struct build_cons<First, Last, false>
0040     {
0041         typedef
0042             build_cons<typename result_of::next<First>::type, Last>
0043         next_build_cons;
0044
0045         typedef cons<
0046             typename result_of::value_of<First>::type
0047           , typename next_build_cons::type>
0048         type;
0049
0050         BOOST_CXX14_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0051         static type
0052         call(First const& f, Last const& l)
0053         {
0054             typename result_of::value_of<First>::type v = *f;
0055             return type(v, next_build_cons::call(fusion::next(f), l));
0056         }
0057     };
0058
0059 }}}
0060
0061 #endif