algorithm/transformation/push_front.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_PUSH_FRONT_07162005_0749)
0008 #define FUSION_PUSH_FRONT_07162005_0749
0009
0010 #include <boost/fusion/support/config.hpp>
0011 #include <boost/fusion/support/detail/as_fusion_element.hpp>
0012 #include <boost/fusion/view/joint_view/joint_view.hpp>
0013 #include <boost/fusion/view/single_view/single_view.hpp>
0014 #include <boost/fusion/support/is_sequence.hpp>
0015 #include <boost/utility/enable_if.hpp>
0016
0017 namespace boost { namespace fusion
0018 {
0019     namespace result_of
0020     {
0021         template <typename Sequence, typename T>
0022         struct push_front
0023         {
0024             typedef fusion::single_view<typename detail::as_fusion_element<T>::type> single_view;
0025             typedef joint_view<single_view const, Sequence> type;
0026         };
0027     }
0028
0029     template <typename Sequence, typename T>
0030     BOOST_CXX14_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0031     inline typename
0032         lazy_enable_if<
0033             traits::is_sequence<Sequence>
0034           , result_of::push_front<Sequence const, T>
0035         >::type
0036     push_front(Sequence const& seq, T const& x)
0037     {
0038         typedef typename result_of::push_front<Sequence const, T> push_front;
0039         typedef typename push_front::single_view single_view;
0040         typedef typename push_front::type result;
0041         single_view x_(x);
0042         return result(x_, seq);
0043     }
0044 }}
0045
0046 #endif
0047