ext-boost/boost/mpl/tag.hpp
2016-03-02 00:27:27 -05:00

53 lines
1023 B
C++

#ifndef BOOST_MPL_TAG_HPP_INCLUDED
#define BOOST_MPL_TAG_HPP_INCLUDED
// Copyright Aleksey Gurtovoy 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/eval_if.hpp>
#include <boost/mpl/void.hpp>
#include <boost/mpl/aux_/has_tag.hpp>
#include <boost/mpl/aux_/config/eti.hpp>
namespace boost { namespace mpl {
namespace aux {
template< typename T > struct tag_impl
{
typedef typename T::tag type;
};
}
template< typename T, typename Default = void_ > struct tag
#if !defined(BOOST_MPL_CFG_MSVC_ETI_BUG)
: if_<
aux::has_tag<T>
, aux::tag_impl<T>
, Default
>::type
{
#else
{
typedef typename eval_if<
aux::has_tag<T>
, aux::tag_impl<T>
, Default
>::type type;
#endif
};
}}
#endif // BOOST_MPL_TAG_HPP_INCLUDED