| |
| #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 |