williamr@2: 
williamr@2: #ifndef BOOST_MPL_AUX_NA_HPP_INCLUDED
williamr@2: #define BOOST_MPL_AUX_NA_HPP_INCLUDED
williamr@2: 
williamr@2: // Copyright Aleksey Gurtovoy 2001-2004
williamr@2: //
williamr@2: // Distributed under the Boost Software License, Version 1.0. 
williamr@2: // (See accompanying file LICENSE_1_0.txt or copy at 
williamr@2: // http://www.boost.org/LICENSE_1_0.txt)
williamr@2: //
williamr@2: // See http://www.boost.org/libs/mpl for documentation.
williamr@2: 
williamr@2: // $Source: /cvsroot/boost/boost/boost/mpl/aux_/na.hpp,v $
williamr@2: // $Date: 2004/11/28 01:37:30 $
williamr@2: // $Revision: 1.6 $
williamr@2: 
williamr@2: #include <boost/mpl/bool.hpp>
williamr@2: #include <boost/mpl/aux_/na_fwd.hpp>
williamr@2: #include <boost/mpl/aux_/config/msvc.hpp>
williamr@2: #include <boost/mpl/aux_/config/ctps.hpp>
williamr@2: 
williamr@2: namespace boost { namespace mpl {
williamr@2: 
williamr@2: template< typename T >
williamr@2: struct is_na
williamr@2:     : false_
williamr@2: {
williamr@2: #if BOOST_WORKAROUND(BOOST_MSVC, < 1300)
williamr@2:     using false_::value;
williamr@2: #endif
williamr@2: };
williamr@2: 
williamr@2: template<>
williamr@2: struct is_na<na>
williamr@2:     : true_
williamr@2: {
williamr@2: #if BOOST_WORKAROUND(BOOST_MSVC, < 1300)
williamr@2:     using true_::value;
williamr@2: #endif
williamr@2: };
williamr@2: 
williamr@2: template< typename T >
williamr@2: struct is_not_na
williamr@2:     : true_
williamr@2: {
williamr@2: #if BOOST_WORKAROUND(BOOST_MSVC, < 1300)
williamr@2:     using true_::value;
williamr@2: #endif
williamr@2: };
williamr@2: 
williamr@2: template<>
williamr@2: struct is_not_na<na>
williamr@2:     : false_
williamr@2: {
williamr@2: #if BOOST_WORKAROUND(BOOST_MSVC, < 1300)
williamr@2:     using false_::value;
williamr@2: #endif
williamr@2: };
williamr@2: 
williamr@2: #if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
williamr@2: template< typename T, typename U > struct if_na
williamr@2: {
williamr@2:     typedef T type;
williamr@2: };
williamr@2: 
williamr@2: template< typename U > struct if_na<na,U>
williamr@2: {
williamr@2:     typedef U type;
williamr@2: };
williamr@2: #else
williamr@2: template< typename T > struct if_na_impl
williamr@2: {
williamr@2:     template< typename U > struct apply
williamr@2:     {
williamr@2:         typedef T type;
williamr@2:     };
williamr@2: };
williamr@2: 
williamr@2: template<> struct if_na_impl<na>
williamr@2: {
williamr@2:     template< typename U > struct apply
williamr@2:     {
williamr@2:         typedef U type;
williamr@2:     };
williamr@2: };
williamr@2: 
williamr@2: template< typename T, typename U > struct if_na
williamr@2:     : if_na_impl<T>::template apply<U>
williamr@2: {
williamr@2: };
williamr@2: #endif
williamr@2: 
williamr@2: }}
williamr@2: 
williamr@2: #endif // BOOST_MPL_AUX_NA_HPP_INCLUDED