Chris@16: 
Chris@16: #ifndef BOOST_MPL_AUX_NA_HPP_INCLUDED
Chris@16: #define BOOST_MPL_AUX_NA_HPP_INCLUDED
Chris@16: 
Chris@16: // Copyright Aleksey Gurtovoy 2001-2004
Chris@16: //
Chris@16: // Distributed under the Boost Software License, Version 1.0. 
Chris@16: // (See accompanying file LICENSE_1_0.txt or copy at 
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: //
Chris@16: // See http://www.boost.org/libs/mpl for documentation.
Chris@16: 
Chris@101: // $Id$
Chris@101: // $Date$
Chris@101: // $Revision$
Chris@16: 
Chris@16: #include <boost/mpl/bool.hpp>
Chris@16: #include <boost/mpl/aux_/na_fwd.hpp>
Chris@16: #include <boost/mpl/aux_/config/msvc.hpp>
Chris@16: #include <boost/mpl/aux_/config/ctps.hpp>
Chris@16: 
Chris@16: namespace boost { namespace mpl {
Chris@16: 
Chris@16: template< typename T >
Chris@16: struct is_na
Chris@16:     : false_
Chris@16: {
Chris@16: #if BOOST_WORKAROUND(BOOST_MSVC, < 1300)
Chris@16:     using false_::value;
Chris@16: #endif
Chris@16: };
Chris@16: 
Chris@16: template<>
Chris@16: struct is_na<na>
Chris@16:     : true_
Chris@16: {
Chris@16: #if BOOST_WORKAROUND(BOOST_MSVC, < 1300)
Chris@16:     using true_::value;
Chris@16: #endif
Chris@16: };
Chris@16: 
Chris@16: template< typename T >
Chris@16: struct is_not_na
Chris@16:     : true_
Chris@16: {
Chris@16: #if BOOST_WORKAROUND(BOOST_MSVC, < 1300)
Chris@16:     using true_::value;
Chris@16: #endif
Chris@16: };
Chris@16: 
Chris@16: template<>
Chris@16: struct is_not_na<na>
Chris@16:     : false_
Chris@16: {
Chris@16: #if BOOST_WORKAROUND(BOOST_MSVC, < 1300)
Chris@16:     using false_::value;
Chris@16: #endif
Chris@16: };
Chris@16: 
Chris@16: #if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
Chris@16: template< typename T, typename U > struct if_na
Chris@16: {
Chris@16:     typedef T type;
Chris@16: };
Chris@16: 
Chris@16: template< typename U > struct if_na<na,U>
Chris@16: {
Chris@16:     typedef U type;
Chris@16: };
Chris@16: #else
Chris@16: template< typename T > struct if_na_impl
Chris@16: {
Chris@16:     template< typename U > struct apply
Chris@16:     {
Chris@16:         typedef T type;
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: template<> struct if_na_impl<na>
Chris@16: {
Chris@16:     template< typename U > struct apply
Chris@16:     {
Chris@16:         typedef U type;
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: template< typename T, typename U > struct if_na
Chris@16:     : if_na_impl<T>::template apply<U>
Chris@16: {
Chris@16: };
Chris@16: #endif
Chris@16: 
Chris@16: }}
Chris@16: 
Chris@16: #endif // BOOST_MPL_AUX_NA_HPP_INCLUDED