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// Boost.TypeErasure library
//
// Copyright 2012 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)
//
// $Id$
#ifndef BOOST_TYPE_ERASURE_FREE_HPP_INCLUDED
#define BOOST_TYPE_ERASURE_FREE_HPP_INCLUDED
#include <boost/preprocessor/repetition/enum.hpp>
#include <boost/preprocessor/repetition/enum_trailing.hpp>
#include <boost/preprocessor/repetition/enum_params.hpp>
#include <boost/preprocessor/repetition/enum_shifted_params.hpp>
#include <boost/preprocessor/repetition/enum_params_with_a_default.hpp>
#include <boost/preprocessor/repetition/enum_binary_params.hpp>
#include <boost/preprocessor/cat.hpp>
#include <boost/type_traits/remove_reference.hpp>
#include <boost/type_traits/remove_cv.hpp>
#include <boost/mpl/eval_if.hpp>
#include <boost/mpl/identity.hpp>
#include <boost/mpl/int.hpp>
#include <boost/mpl/next.hpp>
#include <boost/type_erasure/detail/macro.hpp>
#include <boost/type_erasure/detail/const.hpp>
#include <boost/type_erasure/config.hpp>
#include <boost/type_erasure/derived.hpp>
#include <boost/type_erasure/rebind_any.hpp>
#include <boost/type_erasure/param.hpp>
#include <boost/type_erasure/is_placeholder.hpp>
#include <boost/type_erasure/call.hpp>
#include <boost/type_erasure/concept_interface.hpp>
#if defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES) || defined(BOOST_NO_CXX11_RVALUE_REFERENCES) || defined(BOOST_TYPE_ERASURE_DOXYGEN)
namespace boost {
namespace type_erasure {
namespace detail {
template<BOOST_PP_ENUM_PARAMS_WITH_A_DEFAULT(BOOST_TYPE_ERASURE_MAX_ARITY, class T, void)>
struct first_placeholder {
typedef typename ::boost::mpl::eval_if<is_placeholder<T0>,
::boost::mpl::identity<T0>,
first_placeholder<BOOST_PP_ENUM_SHIFTED_PARAMS(BOOST_TYPE_ERASURE_MAX_ARITY, T)>
>::type type;
};
template<>
struct first_placeholder<> {};
template<BOOST_PP_ENUM_PARAMS_WITH_A_DEFAULT(BOOST_TYPE_ERASURE_MAX_ARITY, class T, void)>
struct first_placeholder_index :
::boost::mpl::eval_if<is_placeholder<T0>,
::boost::mpl::int_<0>,
::boost::mpl::next<first_placeholder_index<BOOST_PP_ENUM_SHIFTED_PARAMS(BOOST_TYPE_ERASURE_MAX_ARITY, T)> >
>::type
{};
}
}
}
/** INTERNAL ONLY */
#define BOOST_TYPE_ERASURE_FREE_QUALIFIED_ID(seq, N) \
BOOST_TYPE_ERASURE_QUALIFIED_NAME(seq)<R(BOOST_PP_ENUM_PARAMS(N, T))>
/** INTERNAL ONLY */
#define BOOST_TYPE_ERASURE_FREE_UNQUALIFIED_PARAM_TYPE(z, n, data) \
typename ::boost::remove_cv<typename ::boost::remove_reference<BOOST_PP_CAT(T, n)>::type>::type
/** INTERNAL ONLY */
#define BOOST_TYPE_ERASURE_FREE_PARAM_TYPE(z, n, data) \
typename ::boost::mpl::eval_if_c<(_boost_type_erasure_free_p_idx::value == n), \
::boost::type_erasure::detail::maybe_const_this_param<BOOST_PP_CAT(T, n), Base>, \
::boost::type_erasure::as_param<Base, BOOST_PP_CAT(T, n)> \
>::type BOOST_PP_CAT(t, n)
#ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
/** INTERNAL ONLY */
#define BOOST_TYPE_ERASURE_FREE_FORWARD_I(z, n, data) ::std::forward<BOOST_PP_CAT(T, n)>(BOOST_PP_CAT(t, n))
/** INTERNAL ONLY */
#define BOOST_TYPE_ERASURE_FREE_FORWARD(n) BOOST_PP_ENUM(n, BOOST_TYPE_ERASURE_FREE_FORWARD_I, ~)
/** INTERNAL ONLY */
#define BOOST_TYPE_ERASURE_FREE_FORWARD_PARAM_I(z, n, data) \
::std::forward<typename ::boost::mpl::eval_if_c<(_boost_type_erasure_free_p_idx::value == n), \
::boost::type_erasure::detail::maybe_const_this_param<BOOST_PP_CAT(T, n), Base>, \
::boost::type_erasure::as_param<Base, BOOST_PP_CAT(T, n)> \
>::type>(BOOST_PP_CAT(t, n))
#else
#define BOOST_TYPE_ERASURE_FREE_FORWARD(n) BOOST_PP_ENUM_PARAMS(n, t)
#define BOOST_TYPE_ERASURE_FREE_FORWARD_PARAM_I(z, n, data) BOOST_PP_CAT(t, n)
#endif
/** INTERNAL ONLY */
#define BOOST_TYPE_ERASURE_FREE_II(qual_name, concept_name, function_name, N) \
BOOST_TYPE_ERASURE_OPEN_NAMESPACE(qual_name) \
\
template<class Sig> \
struct concept_name; \
\
template<class R BOOST_PP_ENUM_TRAILING_PARAMS(N, class T)> \
struct concept_name<R(BOOST_PP_ENUM_PARAMS(N, T))> { \
static R apply(BOOST_PP_ENUM_BINARY_PARAMS(N, T, t)) \
{ return function_name(BOOST_TYPE_ERASURE_FREE_FORWARD(N)); } \
}; \
\
template<BOOST_PP_ENUM_PARAMS(N, class T)> \
struct concept_name<void(BOOST_PP_ENUM_PARAMS(N, T))> { \
static void apply(BOOST_PP_ENUM_BINARY_PARAMS(N, T, t)) \
{ function_name(BOOST_TYPE_ERASURE_FREE_FORWARD(N)); } \
}; \
\
BOOST_TYPE_ERASURE_CLOSE_NAMESPACE(qual_name) \
\
namespace boost { \
namespace type_erasure { \
\
template<class R BOOST_PP_ENUM_TRAILING_PARAMS(N, class T), class Base> \
struct concept_interface< \
BOOST_TYPE_ERASURE_FREE_QUALIFIED_ID(qual_name, N), \
Base, \
typename ::boost::type_erasure::detail::first_placeholder< \
BOOST_PP_ENUM(N, BOOST_TYPE_ERASURE_FREE_UNQUALIFIED_PARAM_TYPE, ~)>::type \
> : Base { \
typedef typename ::boost::type_erasure::detail::first_placeholder_index< \
BOOST_PP_ENUM(N, BOOST_TYPE_ERASURE_FREE_UNQUALIFIED_PARAM_TYPE, ~)>::type \
_boost_type_erasure_free_p_idx; \
friend typename ::boost::type_erasure::rebind_any<Base, R>::type function_name( \
BOOST_PP_ENUM(N, BOOST_TYPE_ERASURE_FREE_PARAM_TYPE, ~)) \
{ \
return ::boost::type_erasure::call( \
BOOST_TYPE_ERASURE_FREE_QUALIFIED_ID(qual_name, N)() \
BOOST_PP_ENUM_TRAILING(N, BOOST_TYPE_ERASURE_FREE_FORWARD_PARAM_I, ~)); \
} \
}; \
\
} \
}
#else
namespace boost {
namespace type_erasure {
template<int... N>
struct index_list {};
namespace detail {
template<class... T>
struct first_placeholder;
template<class T0, class... T>
struct first_placeholder<T0, T...> {
typedef typename ::boost::mpl::eval_if<is_placeholder<T0>,
::boost::mpl::identity<T0>,
first_placeholder<T...>
>::type type;
};
template<>
struct first_placeholder<> {};
template<class... T>
struct first_placeholder_index;
template<class T0, class... T>
struct first_placeholder_index<T0, T...> :
::boost::mpl::eval_if<is_placeholder<T0>,
::boost::mpl::int_<0>,
::boost::mpl::next<first_placeholder_index<T...> >
>::type
{};
template<class Sig>
struct transform_free_signature;
template<class T, int N>
struct push_back_index;
template<int... N, int X>
struct push_back_index<index_list<N...>, X>
{
typedef index_list<N..., X> type;
};
template<int N>
struct make_index_list {
typedef typename push_back_index<
typename make_index_list<N-1>::type,
N-1
>::type type;
};
template<>
struct make_index_list<0> {
typedef index_list<> type;
};
}
}
}
/** INTERNAL ONLY */
#define BOOST_TYPE_ERASURE_FREE_II(qual_name, concept_name, function_name, N) \
BOOST_TYPE_ERASURE_OPEN_NAMESPACE(qual_name) \
\
template<class Sig> \
struct concept_name; \
\
template<class R, class... T> \
struct concept_name<R(T...)> { \
static R apply(T... t) \
{ return function_name(std::forward<T>(t)...); } \
}; \
\
template<class... T> \
struct concept_name<void(T...)> { \
static void apply(T... t) \
{ function_name(std::forward<T>(t)...); } \
}; \
\
BOOST_TYPE_ERASURE_CLOSE_NAMESPACE(qual_name) \
\
namespace boost { \
namespace type_erasure { \
\
template<class Sig, class Base, class Idx> \
struct inject ## concept_name; \
template<class R, class... T, class Base, int... I> \
struct inject ## concept_name<R(T...), Base, index_list<I...> > : Base {\
typedef typename ::boost::type_erasure::detail::first_placeholder_index< \
typename ::boost::remove_cv< \
typename ::boost::remove_reference<T>::type \
>::type... \
>::type _boost_type_erasure_free_p_idx; \
friend typename ::boost::type_erasure::rebind_any<Base, R>::type\
function_name( \
typename ::boost::mpl::eval_if_c<(_boost_type_erasure_free_p_idx::value == I), \
::boost::type_erasure::detail::maybe_const_this_param<T, Base>, \
::boost::type_erasure::as_param<Base, T> \
>::type... t) \
{ \
return ::boost::type_erasure::call( \
BOOST_TYPE_ERASURE_QUALIFIED_NAME(qual_name)<R(T...)>(),\
std::forward<typename ::boost::mpl::eval_if_c<(_boost_type_erasure_free_p_idx::value == I), \
::boost::type_erasure::detail::maybe_const_this_param<T, Base>, \
::boost::type_erasure::as_param<Base, T> \
>::type>(t)...); \
} \
}; \
\
template<class R, class... T, class Base> \
struct concept_interface< \
BOOST_TYPE_ERASURE_QUALIFIED_NAME(qual_name)<R(T...)>, \
Base, \
typename ::boost::type_erasure::detail::first_placeholder< \
typename ::boost::remove_cv<typename ::boost::remove_reference<T>::type>::type...>::type \
> : inject ## concept_name<R(T...), Base, typename ::boost::type_erasure::detail::make_index_list<sizeof...(T)>::type>\
{}; \
\
} \
}
#endif
/** INTERNAL ONLY */
#define BOOST_TYPE_ERASURE_FREE_I(namespace_name, concept_name, function_name, N)\
BOOST_TYPE_ERASURE_FREE_II(namespace_name, concept_name, function_name, N)
/**
* \brief Defines a primitive concept for a free function.
*
* \param qualified_name should be a preprocessor sequence
* of the form (namespace1)(namespace2)...(concept_name).
* \param function_name is the name of the function.
* \param N is the number of arguments of the function.
*
* The declaration of the concept is
* \code
* template<class Sig>
* struct ::namespace1::namespace2::...::concept_name;
* \endcode
* where Sig is a function type giving the
* signature of the function.
*
* This macro can only be used in the global namespace.
*
* Example:
*
* \code
* BOOST_TYPE_ERASURE_FREE((boost)(has_to_string), to_string, 1)
* \endcode
*/
#define BOOST_TYPE_ERASURE_FREE(qualified_name, function_name, N) \
BOOST_TYPE_ERASURE_FREE_I( \
qualified_name, \
BOOST_PP_SEQ_ELEM(BOOST_PP_DEC(BOOST_PP_SEQ_SIZE(qualified_name)), qualified_name), \
function_name, \
N)
#endif
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