1 /*============================================================================= 2 Copyright (c) 2001-2011 Joel de Guzman 3 Copyright (c) 2011 Eric Niebler 4 5 Distributed under the Boost Software License, Version 1.0. (See accompanying 6 file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) 7 ==============================================================================*/ 8 #if !defined(BOOST_FUSION_SINGLE_VIEW_VALUE_OF_IMPL_05052005_0324) 9 #define BOOST_FUSION_SINGLE_VIEW_VALUE_OF_IMPL_05052005_0324 10 11 #include <boost/fusion/support/config.hpp> 12 #include <boost/mpl/int.hpp> 13 #include <boost/mpl/assert.hpp> 14 #include <boost/mpl/equal_to.hpp> 15 16 namespace boost { namespace fusion 17 { 18 struct single_view_iterator_tag; 19 20 namespace extension 21 { 22 template <typename Tag> 23 struct value_of_impl; 24 25 template <> 26 struct value_of_impl<single_view_iterator_tag> 27 { 28 template <typename Iterator> 29 struct apply 30 { 31 BOOST_MPL_ASSERT((mpl::equal_to<typename Iterator::position, mpl::int_<0> >)); 32 typedef typename Iterator::value_type type; 33 }; 34 }; 35 } 36 }} 37 38 #endif 39 40 41