set/aux_/at_impl.hpp

0001
0002 #ifndef BOOST_MPL_SET_AUX_AT_IMPL_HPP_INCLUDED
0003 #define BOOST_MPL_SET_AUX_AT_IMPL_HPP_INCLUDED
0004
0005 // Copyright Aleksey Gurtovoy 2003-2004
0006 //
0007 // Distributed under the Boost Software License, Version 1.0.
0008 // (See accompanying file LICENSE_1_0.txt or copy at
0009 // http://www.boost.org/LICENSE_1_0.txt)
0010 //
0011 // See http://www.boost.org/libs/mpl for documentation.
0012
0013 // $Id$
0014 // $Date$
0015 // $Revision$
0016
0017 #include <boost/mpl/at_fwd.hpp>
0018 #include <boost/mpl/set/aux_/has_key_impl.hpp>
0019 #include <boost/mpl/set/aux_/tag.hpp>
0020 #include <boost/mpl/if.hpp>
0021 #include <boost/mpl/void.hpp>
0022
0023 namespace boost { namespace mpl {
0024
0025 template<>
0026 struct at_impl< aux::set_tag >
0027 {
0028     template< typename Set, typename T > struct apply
0029     {
0030         typedef typename if_<
0031               has_key_impl<aux::set_tag>::apply<Set,T>
0032             , T
0033             , void_
0034             >::type type;
0035     };
0036 };
0037
0038 }}
0039
0040 #endif // BOOST_MPL_SET_AUX_AT_IMPL_HPP_INCLUDED