boost/parameter/aux_/tag.hpp
// Copyright David Abrahams 2005.
// Copyright Cromwell D. Enage 2017.
// 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)
#ifndef BOOST_PARAMETER_AUX_TAG_DWA2005610_HPP
#define BOOST_PARAMETER_AUX_TAG_DWA2005610_HPP
#include <boost/parameter/aux_/unwrap_cv_reference.hpp>
#include <boost/parameter/aux_/tagged_argument.hpp>
#include <boost/parameter/config.hpp>
#if defined(BOOST_PARAMETER_CAN_USE_MP11) && \
!BOOST_WORKAROUND(BOOST_MSVC, >= 1910)
// MSVC-14.1+ assigns rvalue references to tagged_argument instances
// instead of tagged_argument_rref instances with this code.
#include <boost/mp11/integral.hpp>
#include <boost/mp11/utility.hpp>
#include <type_traits>
namespace boost { namespace parameter { namespace aux {
template <typename Keyword, typename Arg>
struct tag_if_lvalue_reference
{
using type = ::boost::parameter::aux::tagged_argument_list_of_1<
::boost::parameter::aux::tagged_argument<
Keyword
, typename ::boost::parameter::aux
::unwrap_cv_reference<Arg>::type
>
>;
};
template <typename Keyword, typename Arg>
struct tag_if_scalar
{
using type = ::boost::parameter::aux::tagged_argument_list_of_1<
::boost::parameter::aux
::tagged_argument<Keyword,typename ::std::add_const<Arg>::type>
>;
};
template <typename Keyword, typename Arg>
using tag_if_otherwise = ::boost::mp11::mp_if<
::std::is_scalar<typename ::std::remove_const<Arg>::type>
, ::boost::parameter::aux::tag_if_scalar<Keyword,Arg>
, ::boost::mp11::mp_identity<
::boost::parameter::aux::tagged_argument_list_of_1<
::boost::parameter::aux::tagged_argument_rref<Keyword,Arg>
>
>
>;
template <typename Keyword, typename Arg>
using tag = ::boost::mp11::mp_if<
::boost::mp11::mp_if<
::std::is_lvalue_reference<Arg>
, ::boost::mp11::mp_true
, ::boost::parameter::aux::is_cv_reference_wrapper<Arg>
>
, ::boost::parameter::aux::tag_if_lvalue_reference<Keyword,Arg>
, ::boost::parameter::aux::tag_if_otherwise<Keyword,Arg>
>;
}}} // namespace boost::parameter::aux_
#elif defined(BOOST_PARAMETER_HAS_PERFECT_FORWARDING)
#include <boost/mpl/bool.hpp>
#include <boost/mpl/if.hpp>
#include <boost/mpl/eval_if.hpp>
#include <boost/mpl/identity.hpp>
#include <boost/type_traits/add_const.hpp>
#include <boost/type_traits/is_scalar.hpp>
#include <boost/type_traits/is_lvalue_reference.hpp>
#include <boost/type_traits/remove_const.hpp>
namespace boost { namespace parameter { namespace aux {
template <typename Keyword, typename ActualArg>
struct tag
{
typedef typename ::boost::parameter::aux
::unwrap_cv_reference<ActualArg>::type Arg;
typedef typename ::boost::add_const<Arg>::type ConstArg;
typedef typename ::boost::remove_const<Arg>::type MutArg;
typedef typename ::boost::mpl::eval_if<
typename ::boost::mpl::if_<
::boost::is_lvalue_reference<ActualArg>
, ::boost::mpl::true_
, ::boost::parameter::aux::is_cv_reference_wrapper<ActualArg>
>::type
, ::boost::mpl::identity<
#if defined(BOOST_PARAMETER_CAN_USE_MP11)
::boost::parameter::aux::tagged_argument_list_of_1<
#endif
::boost::parameter::aux::tagged_argument<Keyword,Arg>
#if defined(BOOST_PARAMETER_CAN_USE_MP11)
>
#endif
>
, ::boost::mpl::if_<
::boost::is_scalar<MutArg>
#if defined(BOOST_PARAMETER_CAN_USE_MP11)
, ::boost::parameter::aux::tagged_argument_list_of_1<
::boost::parameter::aux::tagged_argument<Keyword,ConstArg>
>
, ::boost::parameter::aux::tagged_argument_list_of_1<
::boost::parameter::aux::tagged_argument_rref<Keyword,Arg>
>
#else
, ::boost::parameter::aux::tagged_argument<Keyword,ConstArg>
, ::boost::parameter::aux::tagged_argument_rref<Keyword,Arg>
#endif
>
>::type type;
};
}}} // namespace boost::parameter::aux_
#else // !defined(BOOST_PARAMETER_HAS_PERFECT_FORWARDING)
namespace boost { namespace parameter { namespace aux {
template <
typename Keyword
, typename Arg
#if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x564))
, typename = typename ::boost::parameter::aux
::is_cv_reference_wrapper<Arg>::type
#endif
>
struct tag
{
typedef ::boost::parameter::aux::tagged_argument<
Keyword
, typename ::boost::parameter::aux::unwrap_cv_reference<Arg>::type
> type;
};
}}} // namespace boost::parameter::aux_
#if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x564))
#include <boost/mpl/bool.hpp>
#include <boost/type_traits/remove_reference.hpp>
namespace boost { namespace parameter { namespace aux {
template <typename Keyword, typename Arg>
struct tag<Keyword,Arg,::boost::mpl::false_>
{
typedef ::boost::parameter::aux::tagged_argument<
Keyword
, typename ::boost::remove_reference<Arg>::type
> type;
};
}}} // namespace boost::parameter::aux_
#endif // Borland workarounds needed.
#endif // MP11 or perfect forwarding support
#endif // include guard