Chris@16: /* Copyright 2006-2009 Joaquin M Lopez Munoz.
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/flyweight for library home page.
Chris@16:  */
Chris@16: 
Chris@16: #ifndef BOOST_FLYWEIGHT_DETAIL_IS_PLACEHOLDER_EXPR_HPP
Chris@16: #define BOOST_FLYWEIGHT_DETAIL_IS_PLACEHOLDER_EXPR_HPP
Chris@16: 
Chris@101: #if defined(_MSC_VER)
Chris@16: #pragma once
Chris@16: #endif
Chris@16: 
Chris@16: #include <boost/type_traits/is_same.hpp>
Chris@16: #include <boost/mpl/apply.hpp>
Chris@16: #include <boost/mpl/aux_/lambda_support.hpp>
Chris@16: #include <boost/mpl/not.hpp>
Chris@16: #include <boost/preprocessor/facilities/intercept.hpp>
Chris@16: #include <boost/preprocessor/repetition/enum_params.hpp>
Chris@16: 
Chris@16: namespace boost{
Chris@16: 
Chris@16: namespace flyweights{
Chris@16: 
Chris@16: namespace detail{
Chris@16: 
Chris@16: /* is_placeholder_expression<T> indicates whether T is an
Chris@16:  * MPL placeholder expression.
Chris@16:  */
Chris@16: 
Chris@16: template<typename T>
Chris@16: struct is_placeholder_expression_helper
Chris@16: {
Chris@16:   template<
Chris@16:     BOOST_PP_ENUM_PARAMS(
Chris@16:       BOOST_MPL_LIMIT_METAFUNCTION_ARITY,typename BOOST_PP_INTERCEPT)
Chris@16:   >
Chris@16:   struct apply{
Chris@16:     typedef int type;
Chris@16:   };
Chris@16: 
Chris@16:   BOOST_MPL_AUX_LAMBDA_SUPPORT(1,is_placeholder_expression_helper,(T))
Chris@16: };
Chris@16: 
Chris@16: template<typename T>
Chris@16: struct is_placeholder_expression:
Chris@16:   mpl::not_<is_same<
Chris@16:     typename mpl::apply<
Chris@16:       is_placeholder_expression_helper<T>,
Chris@16:       BOOST_PP_ENUM_PARAMS(
Chris@16:         BOOST_MPL_LIMIT_METAFUNCTION_ARITY,int BOOST_PP_INTERCEPT)
Chris@16:     >::type,
Chris@16:     int
Chris@16:   > >
Chris@16: {};
Chris@16: 
Chris@16: } /* namespace flyweights::detail */
Chris@16: 
Chris@16: } /* namespace flyweights */
Chris@16: 
Chris@16: } /* namespace boost */
Chris@16: 
Chris@16: #endif