| /*============================================================================= |
| Copyright (c) 2001-2010 Joel de Guzman |
| |
| Distributed under the Boost Software License, Version 1.0. (See accompanying |
| file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
| ==============================================================================*/ |
| #if !defined(BOOST_SPIRIT_UNUSED_APRIL_16_2006_0616PM) |
| #define BOOST_SPIRIT_UNUSED_APRIL_16_2006_0616PM |
| |
| #if defined(_MSC_VER) |
| #pragma once |
| #endif |
| |
| #include <boost/fusion/include/unused.hpp> |
| #include <boost/mpl/bool.hpp> |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // implement streaming operators for unused_type for older versions of Fusion |
| #if !defined(BOOST_FUSION_UNUSED_HAS_IO) |
| namespace boost { namespace fusion |
| { |
| namespace detail |
| { |
| struct unused_only |
| { |
| unused_only(unused_type const&) {} |
| }; |
| } |
| |
| template <typename Out> |
| inline Out& operator<<(Out& out, detail::unused_only const&) |
| { |
| return out; |
| } |
| |
| template <typename In> |
| inline In& operator>>(In& in, unused_type&) |
| { |
| return in; |
| } |
| }} |
| #endif |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| namespace boost { namespace spirit |
| { |
| /////////////////////////////////////////////////////////////////////////// |
| // since boost::fusion now supports exactly what we need, unused is simply |
| // imported from the fusion namespace |
| /////////////////////////////////////////////////////////////////////////// |
| using boost::fusion::unused_type; |
| using boost::fusion::unused; |
| |
| /////////////////////////////////////////////////////////////////////////// |
| namespace traits |
| { |
| // We use this test to detect if the argument is not an unused_type |
| template <typename T> struct not_is_unused : mpl::true_ {}; |
| template <> struct not_is_unused<unused_type> : mpl::false_ {}; |
| } |
| }} |
| |
| #endif |