/* Copyright 2006-2008 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_HOLDER_TAG_HPP | |
#define BOOST_FLYWEIGHT_HOLDER_TAG_HPP | |
#if defined(_MSC_VER)&&(_MSC_VER>=1200) | |
#pragma once | |
#endif | |
#include <boost/config.hpp> /* keep it first to prevent nasty warns in MSVC */ | |
#include <boost/parameter/parameters.hpp> | |
#include <boost/type_traits/is_base_and_derived.hpp> | |
namespace boost{ | |
namespace flyweights{ | |
/* Three ways to indicate that a given class T is a holder specifier: | |
* 1. Make it derived from holder_marker. | |
* 2. Specialize is_holder to evaluate to boost::mpl::true_. | |
* 3. Pass it as holder<T> when defining a flyweight type. | |
*/ | |
struct holder_marker{}; | |
template<typename T> | |
struct is_holder:is_base_and_derived<holder_marker,T> | |
{}; | |
template<typename T=parameter::void_> | |
struct holder:parameter::template_keyword<holder<>,T> | |
{}; | |
} /* namespace flyweights */ | |
} /* namespace boost */ | |
#endif |