boost/type_erasure/detail/extract_concept.hpp
// Boost.TypeErasure library
//
// Copyright 2011 Steven Watanabe
//
// 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)
//
// $Id$
#if !defined(BOOST_PP_IS_ITERATING)
#ifndef BOOST_TYPE_ERASURE_DETAIL_EXTRACT_CONCEPT_HPP_INCLUDED
#define BOOST_TYPE_ERASURE_DETAIL_EXTRACT_CONCEPT_HPP_INCLUDED
#include <boost/mpl/eval_if.hpp>
#include <boost/mpl/identity.hpp>
#include <boost/type_traits/remove_cv.hpp>
#include <boost/type_traits/remove_reference.hpp>
#include <boost/preprocessor/cat.hpp>
#include <boost/preprocessor/inc.hpp>
#include <boost/preprocessor/iteration/iterate.hpp>
#include <boost/preprocessor/repetition/repeat.hpp>
#include <boost/preprocessor/repetition/enum_params.hpp>
#include <boost/type_erasure/is_placeholder.hpp>
#include <boost/type_erasure/concept_of.hpp>
#include <boost/type_erasure/config.hpp>
namespace boost {
namespace type_erasure {
namespace detail {
template<class T, class U>
struct combine_concepts;
template<class T>
struct combine_concepts<T, T> { typedef T type; };
template<class T>
struct combine_concepts<T, void> { typedef T type; };
template<class T>
struct combine_concepts<void, T> { typedef T type; };
template<>
struct combine_concepts<void, void> { typedef void type; };
template<class T, class U>
struct maybe_extract_concept
{
typedef typename ::boost::mpl::eval_if<
::boost::type_erasure::is_placeholder<
typename ::boost::remove_cv<
typename ::boost::remove_reference<T>::type
>::type
>,
::boost::type_erasure::concept_of<typename ::boost::remove_reference<U>::type>,
::boost::mpl::identity<void>
>::type type;
};
#if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
template<class Args, class... U>
struct extract_concept;
template<class R, class T0, class... T, class U0, class... U>
struct extract_concept<R(T0, T...), U0, U...>
{
typedef typename ::boost::type_erasure::detail::combine_concepts<
typename ::boost::type_erasure::detail::maybe_extract_concept<
T0, U0
>::type,
typename ::boost::type_erasure::detail::extract_concept<
void(T...),
U...
>::type
>::type type;
};
template<>
struct extract_concept<void()>
{
typedef void type;
};
#else
//#endif
#define BOOST_PP_FILENAME_1 <boost/type_erasure/detail/extract_concept.hpp>
#define BOOST_PP_ITERATION_LIMITS (1, BOOST_TYPE_ERASURE_MAX_ARITY)
#include BOOST_PP_ITERATE()
#endif
}
}
}
#endif
#else
#define N BOOST_PP_ITERATION()
#define BOOST_TYPE_ERASURE_EXTRACT_CONCEPT(z, n, data) \
typedef typename ::boost::type_erasure::detail::combine_concepts< \
typename ::boost::type_erasure::detail::maybe_extract_concept< \
BOOST_PP_CAT(T, n), BOOST_PP_CAT(U, n) \
>::type, \
BOOST_PP_CAT(concept, n) \
>::type BOOST_PP_CAT(concept, BOOST_PP_INC(n));
template<
BOOST_PP_ENUM_PARAMS(N, class T),
BOOST_PP_ENUM_PARAMS(N, class U)>
struct BOOST_PP_CAT(extract_concept, N)
{
typedef void concept0;
BOOST_PP_REPEAT(N, BOOST_TYPE_ERASURE_EXTRACT_CONCEPT, ~)
typedef BOOST_PP_CAT(concept, N) type;
};
#undef BOOST_TYPE_ERASURE_EXTRACT_CONCEPT
#undef N
#endif