Chris@16: /*=============================================================================
Chris@16:     Copyright (c) 2001-2011 Joel de Guzman
Chris@16:     Copyright (c) 2001-2011 Hartmut Kaiser
Chris@16: 
Chris@16:     Distributed under the Boost Software License, Version 1.0. (See accompanying
Chris@16:     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: ==============================================================================*/
Chris@16: #if !defined(BOOST_SPIRIT_UNUSED_APRIL_16_2006_0616PM)
Chris@16: #define BOOST_SPIRIT_UNUSED_APRIL_16_2006_0616PM
Chris@16: 
Chris@16: #if defined(_MSC_VER)
Chris@16: #pragma once
Chris@16: #endif
Chris@16: 
Chris@16: #include <boost/config.hpp>
Chris@16: #include <boost/mpl/bool.hpp>
Chris@16: 
Chris@16: #if defined(BOOST_MSVC)
Chris@16: # pragma warning(push)
Chris@16: # pragma warning(disable: 4522) // multiple assignment operators specified warning
Chris@16: #endif
Chris@16: 
Chris@16: ///////////////////////////////////////////////////////////////////////////////
Chris@16: namespace boost { namespace spirit
Chris@16: {
Chris@16:     ///////////////////////////////////////////////////////////////////////////
Chris@16:     // We do not import fusion ::unused_type anymore to avoid boost::fusion
Chris@16:     // being turned into an associate namespace for boost::spirit, as this
Chris@16:     // interferes with ADL in unexpected ways. We rather copy the full 
Chris@16:     // unused_type implementation from boost::fusion.
Chris@16:     ///////////////////////////////////////////////////////////////////////////
Chris@16:     struct unused_type
Chris@16:     {
Chris@16:         unused_type()
Chris@16:         {
Chris@16:         }
Chris@16: 
Chris@16:         template <typename T>
Chris@16:         unused_type(T const&)
Chris@16:         {
Chris@16:         }
Chris@16: 
Chris@16:         template <typename T>
Chris@16:         unused_type const&
Chris@16:         operator=(T const&) const
Chris@16:         {
Chris@16:             return *this;
Chris@16:         }
Chris@16: 
Chris@16:         template <typename T>
Chris@16:         unused_type&
Chris@16:         operator=(T const&)
Chris@16:         {
Chris@16:             return *this;
Chris@16:         }
Chris@16: 
Chris@16:         unused_type const&
Chris@16:         operator=(unused_type const&) const
Chris@16:         {
Chris@16:             return *this;
Chris@16:         }
Chris@16: 
Chris@16:         unused_type&
Chris@16:         operator=(unused_type const&)
Chris@16:         {
Chris@16:             return *this;
Chris@16:         }
Chris@16:     };
Chris@16: 
Chris@16:     unused_type const unused = unused_type();
Chris@16: 
Chris@16:     namespace detail
Chris@16:     {
Chris@16:         struct unused_only
Chris@16:         {
Chris@16:             unused_only(unused_type const&) {}
Chris@16:         };
Chris@16:     }
Chris@16: 
Chris@16:     template <typename Out>
Chris@16:     inline Out& operator<<(Out& out, detail::unused_only const&)
Chris@16:     {
Chris@16:         return out;
Chris@16:     }
Chris@16: 
Chris@16:     template <typename In>
Chris@16:     inline In& operator>>(In& in, unused_type&)
Chris@16:     {
Chris@16:         return in;
Chris@16:     }
Chris@16: 
Chris@16:     ///////////////////////////////////////////////////////////////////////////
Chris@16:     namespace traits
Chris@16:     {
Chris@16:         // We use this test to detect if the argument is not an unused_type
Chris@16:         template <typename T> struct not_is_unused : mpl::true_ {};
Chris@16:         template <> struct not_is_unused<unused_type> : mpl::false_ {};
Chris@16:     }
Chris@16: }}
Chris@16: 
Chris@16: #if defined(BOOST_MSVC)
Chris@16: # pragma warning(pop)
Chris@16: #endif
Chris@16: 
Chris@16: #endif