Chris@16: 
Chris@16: #ifndef BOOST_MPL_IS_PLACEHOLDER_HPP_INCLUDED
Chris@16: #define BOOST_MPL_IS_PLACEHOLDER_HPP_INCLUDED
Chris@16: 
Chris@16: // Copyright Aleksey Gurtovoy 2001-2004
Chris@16: //
Chris@16: // Distributed under the Boost Software License, Version 1.0. 
Chris@16: // (See accompanying file LICENSE_1_0.txt or copy at 
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: //
Chris@16: // See http://www.boost.org/libs/mpl for documentation.
Chris@16: 
Chris@101: // $Id$
Chris@101: // $Date$
Chris@101: // $Revision$
Chris@16: 
Chris@16: #include <boost/mpl/arg_fwd.hpp>
Chris@16: #include <boost/mpl/bool.hpp>
Chris@16: #include <boost/mpl/aux_/yes_no.hpp>
Chris@16: #include <boost/mpl/aux_/type_wrapper.hpp>
Chris@16: #include <boost/mpl/aux_/nttp_decl.hpp>
Chris@16: #include <boost/mpl/aux_/config/ctps.hpp>
Chris@16: #include <boost/mpl/aux_/config/static_constant.hpp>
Chris@16: 
Chris@16: namespace boost { namespace mpl {
Chris@16: 
Chris@16: #if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
Chris@16: 
Chris@16: template< typename T >
Chris@16: struct is_placeholder
Chris@16:     : bool_<false>
Chris@16: {
Chris@16: };
Chris@16: 
Chris@16: template< BOOST_MPL_AUX_NTTP_DECL(int, N) >
Chris@16: struct is_placeholder< arg<N> >
Chris@16:     : bool_<true>
Chris@16: {
Chris@16: };
Chris@16: 
Chris@16: #else
Chris@16: 
Chris@16: namespace aux {
Chris@16: 
Chris@16: aux::no_tag is_placeholder_helper(...);
Chris@16: 
Chris@16: template< BOOST_MPL_AUX_NTTP_DECL(int, N) >
Chris@16: aux::yes_tag is_placeholder_helper(aux::type_wrapper< arg<N> >*);
Chris@16: 
Chris@16: } // namespace aux
Chris@16: 
Chris@16: template< typename T >
Chris@16: struct is_placeholder
Chris@16: {
Chris@16:     static aux::type_wrapper<T>* get();
Chris@16:     BOOST_STATIC_CONSTANT(bool, value = 
Chris@16:           sizeof(aux::is_placeholder_helper(get())) == sizeof(aux::yes_tag)
Chris@16:         );
Chris@16:     
Chris@16:     typedef bool_<value> type;
Chris@16: };
Chris@16: 
Chris@16: #endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
Chris@16: 
Chris@16: }}
Chris@16: 
Chris@16: #endif // BOOST_MPL_IS_PLACEHOLDER_HPP_INCLUDED