/* Copyright 2006-2009 Joaquin M Lopez Munoz. | |
* 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/flyweight for library home page. | |
*/ | |
#ifndef BOOST_FLYWEIGHT_DETAIL_IS_PLACEHOLDER_EXPR_HPP | |
#define BOOST_FLYWEIGHT_DETAIL_IS_PLACEHOLDER_EXPR_HPP | |
#if defined(_MSC_VER)&&(_MSC_VER>=1200) | |
#pragma once | |
#endif | |
#include <boost/type_traits/is_same.hpp> | |
#include <boost/mpl/apply.hpp> | |
#include <boost/mpl/aux_/lambda_support.hpp> | |
#include <boost/mpl/not.hpp> | |
#include <boost/preprocessor/facilities/intercept.hpp> | |
#include <boost/preprocessor/repetition/enum_params.hpp> | |
namespace boost{ | |
namespace flyweights{ | |
namespace detail{ | |
/* is_placeholder_expression<T> indicates whether T is an | |
* MPL placeholder expression. | |
*/ | |
template<typename T> | |
struct is_placeholder_expression_helper | |
{ | |
template< | |
BOOST_PP_ENUM_PARAMS( | |
BOOST_MPL_LIMIT_METAFUNCTION_ARITY,typename BOOST_PP_INTERCEPT) | |
> | |
struct apply{ | |
typedef int type; | |
}; | |
BOOST_MPL_AUX_LAMBDA_SUPPORT(1,is_placeholder_expression_helper,(T)) | |
}; | |
template<typename T> | |
struct is_placeholder_expression: | |
mpl::not_<is_same< | |
typename mpl::apply< | |
is_placeholder_expression_helper<T>, | |
BOOST_PP_ENUM_PARAMS( | |
BOOST_MPL_LIMIT_METAFUNCTION_ARITY,int BOOST_PP_INTERCEPT) | |
>::type, | |
int | |
> > | |
{}; | |
} /* namespace flyweights::detail */ | |
} /* namespace flyweights */ | |
} /* namespace boost */ | |
#endif |