#ifndef BOOST_MPL_AUX_NA_HPP_INCLUDED #define BOOST_MPL_AUX_NA_HPP_INCLUDED // Copyright Aleksey Gurtovoy 2001-2004 // // 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) // // See http://www.boost.org/libs/mpl for documentation. // $Id$ // $Date$ // $Revision$ #include <boost/mpl/bool.hpp> #include <boost/mpl/aux_/na_fwd.hpp> #include <boost/mpl/aux_/config/msvc.hpp> #include <boost/mpl/aux_/config/ctps.hpp> namespace boost { namespace mpl { template< typename T > struct is_na : false_ { #if BOOST_WORKAROUND(BOOST_MSVC, < 1300) using false_::value; #endif }; template<> struct is_na<na> : true_ { #if BOOST_WORKAROUND(BOOST_MSVC, < 1300) using true_::value; #endif }; template< typename T > struct is_not_na : true_ { #if BOOST_WORKAROUND(BOOST_MSVC, < 1300) using true_::value; #endif }; template<> struct is_not_na<na> : false_ { #if BOOST_WORKAROUND(BOOST_MSVC, < 1300) using false_::value; #endif }; #if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) template< typename T, typename U > struct if_na { typedef T type; }; template< typename U > struct if_na<na,U> { typedef U type; }; #else template< typename T > struct if_na_impl { template< typename U > struct apply { typedef T type; }; }; template<> struct if_na_impl<na> { template< typename U > struct apply { typedef U type; }; }; template< typename T, typename U > struct if_na : if_na_impl<T>::template apply<U> { }; #endif }} #endif // BOOST_MPL_AUX_NA_HPP_INCLUDED