boost/parameter/keyword.hpp
// Copyright Daniel Wallin, 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_KEYWORD_HPP #define BOOST_PARAMETER_KEYWORD_HPP #include <boost/parameter/aux_/tag.hpp> #include <boost/parameter/aux_/default.hpp> #include <boost/parameter/keyword_fwd.hpp> #include <boost/parameter/config.hpp> #if defined(BOOST_PARAMETER_HAS_PERFECT_FORWARDING) #include <boost/core/enable_if.hpp> #include <utility> #if defined(BOOST_PARAMETER_CAN_USE_MP11) #include <boost/mp11/integral.hpp> #include <boost/mp11/utility.hpp> #include <type_traits> #else #include <boost/mpl/bool.hpp> #include <boost/mpl/if.hpp> #include <boost/mpl/eval_if.hpp> #include <boost/type_traits/is_same.hpp> #include <boost/type_traits/is_scalar.hpp> #include <boost/type_traits/is_const.hpp> #endif namespace boost { namespace parameter { // Instances of unique specializations of keyword<...> serve to // associate arguments with parameter names. For example: // // struct rate_; // parameter names // struct skew_; // // namespace // { // keyword<rate_> rate; // keywords // keyword<skew_> skew; // } // // ... // // f(rate = 1, skew = 2.4); template <typename Tag> struct keyword { typedef Tag tag; inline BOOST_CONSTEXPR keyword() { } template <typename T> inline BOOST_CONSTEXPR typename ::boost::lazy_enable_if< #if defined(BOOST_PARAMETER_CAN_USE_MP11) ::boost::mp11::mp_if< ::std::is_scalar<T> , ::boost::mp11::mp_true , ::boost::mp11::mp_if< ::std::is_same< typename Tag::qualifier , ::boost::parameter::in_reference > , ::boost::mp11::mp_true , ::std::is_same< typename Tag::qualifier , ::boost::parameter::forward_reference > > > #else // !defined(BOOST_PARAMETER_CAN_USE_MP11) typename ::boost::mpl::eval_if< ::boost::is_scalar<T> , ::boost::mpl::true_ , ::boost::mpl::eval_if< ::boost::is_same< typename Tag::qualifier , ::boost::parameter::in_reference > , ::boost::mpl::true_ , ::boost::mpl::if_< ::boost::is_same< typename Tag::qualifier , ::boost::parameter::forward_reference > , ::boost::mpl::true_ , ::boost::mpl::false_ > > >::type #endif // BOOST_PARAMETER_CAN_USE_MP11 , ::boost::parameter::aux::tag<Tag,T const&> >::type operator=(T const& x) const { typedef typename ::boost::parameter::aux ::tag<Tag,T const&>::type result; return result(x); } template <typename Default> inline BOOST_CONSTEXPR typename ::boost::enable_if< #if defined(BOOST_PARAMETER_CAN_USE_MP11) ::boost::mp11::mp_if< ::std::is_scalar<Default> , ::boost::mp11::mp_true , ::boost::mp11::mp_if< ::std::is_same< typename Tag::qualifier , ::boost::parameter::in_reference > , ::boost::mp11::mp_true , ::std::is_same< typename Tag::qualifier , ::boost::parameter::forward_reference > > > #else // !defined(BOOST_PARAMETER_CAN_USE_MP11) typename ::boost::mpl::eval_if< ::boost::is_scalar<Default> , ::boost::mpl::true_ , ::boost::mpl::eval_if< ::boost::is_same< typename Tag::qualifier , ::boost::parameter::in_reference > , ::boost::mpl::true_ , ::boost::mpl::if_< ::boost::is_same< typename Tag::qualifier , ::boost::parameter::forward_reference > , ::boost::mpl::true_ , ::boost::mpl::false_ > > >::type #endif // BOOST_PARAMETER_CAN_USE_MP11 , ::boost::parameter::aux::default_<Tag,Default const> >::type operator|(Default const& d) const { return ::boost::parameter::aux::default_<Tag,Default const>(d); } template <typename T> inline BOOST_CONSTEXPR typename ::boost::lazy_enable_if< #if defined(BOOST_PARAMETER_CAN_USE_MP11) ::boost::mp11::mp_if< ::boost::mp11::mp_if< ::std::is_same< typename Tag::qualifier , ::boost::parameter::out_reference > , ::boost::mp11::mp_true , ::std::is_same< typename Tag::qualifier , ::boost::parameter::forward_reference > > , ::boost::mp11::mp_if< ::std::is_const<T> , ::boost::mp11::mp_false , ::boost::mp11::mp_true > , ::boost::mp11::mp_false > #else // !defined(BOOST_PARAMETER_CAN_USE_MP11) typename ::boost::mpl::eval_if< typename ::boost::mpl::if_< ::boost::is_same< typename Tag::qualifier , ::boost::parameter::out_reference > , ::boost::mpl::true_ , ::boost::is_same< typename Tag::qualifier , ::boost::parameter::forward_reference > >::type , ::boost::mpl::if_< ::boost::is_const<T> , ::boost::mpl::false_ , ::boost::mpl::true_ > , ::boost::mpl::false_ >::type #endif // BOOST_PARAMETER_CAN_USE_MP11 , ::boost::parameter::aux::tag<Tag,T&> >::type operator=(T& x) const { typedef typename ::boost::parameter::aux ::tag<Tag,T&>::type result; return result(x); } template <typename Default> inline BOOST_CONSTEXPR typename ::boost::enable_if< #if defined(BOOST_PARAMETER_CAN_USE_MP11) ::boost::mp11::mp_if< ::boost::mp11::mp_if< ::std::is_same< typename Tag::qualifier , ::boost::parameter::out_reference > , ::boost::mp11::mp_true , ::std::is_same< typename Tag::qualifier , ::boost::parameter::forward_reference > > , ::boost::mp11::mp_if< ::std::is_const<Default> , ::boost::mp11::mp_false , ::boost::mp11::mp_true > , ::boost::mp11::mp_false > #else // !defined(BOOST_PARAMETER_CAN_USE_MP11) typename ::boost::mpl::eval_if< typename ::boost::mpl::if_< ::boost::is_same< typename Tag::qualifier , ::boost::parameter::out_reference > , ::boost::mpl::true_ , ::boost::is_same< typename Tag::qualifier , ::boost::parameter::forward_reference > >::type , ::boost::mpl::if_< ::boost::is_const<Default> , ::boost::mpl::false_ , ::boost::mpl::true_ > , ::boost::mpl::false_ >::type #endif // BOOST_PARAMETER_CAN_USE_MP11 , ::boost::parameter::aux::default_<Tag,Default> >::type operator|(Default& d) const { return ::boost::parameter::aux::default_<Tag,Default>(d); } template <typename Default> inline BOOST_CONSTEXPR ::boost::parameter::aux::lazy_default<Tag,Default const> operator||(Default const& d) const { return ::boost::parameter::aux ::lazy_default<Tag,Default const>(d); } template <typename Default> inline BOOST_CONSTEXPR ::boost::parameter::aux::lazy_default<Tag,Default> operator||(Default& d) const { return ::boost::parameter::aux::lazy_default<Tag,Default>(d); } template <typename T> inline BOOST_CONSTEXPR typename ::boost::lazy_enable_if< #if defined(BOOST_PARAMETER_CAN_USE_MP11) ::boost::mp11::mp_if< ::std::is_scalar<T> , ::boost::mp11::mp_false , ::boost::mp11::mp_if< ::std::is_same< typename Tag::qualifier , ::boost::parameter::in_reference > , ::boost::mp11::mp_true , ::std::is_same< typename Tag::qualifier , ::boost::parameter::forward_reference > > > #else // !defined(BOOST_PARAMETER_CAN_USE_MP11) typename ::boost::mpl::eval_if< ::boost::is_scalar<T> , ::boost::mpl::false_ , ::boost::mpl::eval_if< ::boost::is_same< typename Tag::qualifier , ::boost::parameter::in_reference > , ::boost::mpl::true_ , ::boost::mpl::if_< ::boost::is_same< typename Tag::qualifier , ::boost::parameter::forward_reference > , ::boost::mpl::true_ , ::boost::mpl::false_ > > >::type #endif // BOOST_PARAMETER_CAN_USE_MP11 , ::boost::parameter::aux::tag<Tag,T const> >::type operator=(T const&& x) const { typedef typename ::boost::parameter::aux ::tag<Tag,T const>::type result; return result(::std::forward<T const>(x)); } template <typename T> inline BOOST_CONSTEXPR typename ::boost::lazy_enable_if< #if defined(BOOST_PARAMETER_CAN_USE_MP11) ::boost::mp11::mp_if< ::std::is_scalar<T> , ::boost::mp11::mp_false , ::boost::mp11::mp_if< ::std::is_same< typename Tag::qualifier , ::boost::parameter::consume_reference > , ::boost::mp11::mp_true , ::std::is_same< typename Tag::qualifier , ::boost::parameter::forward_reference > > > #else // !defined(BOOST_PARAMETER_CAN_USE_MP11) typename ::boost::mpl::eval_if< ::boost::is_scalar<T> , ::boost::mpl::false_ , ::boost::mpl::eval_if< ::boost::is_same< typename Tag::qualifier , ::boost::parameter::consume_reference > , ::boost::mpl::true_ , ::boost::mpl::if_< ::boost::is_same< typename Tag::qualifier , ::boost::parameter::forward_reference > , ::boost::mpl::true_ , ::boost::mpl::false_ > > >::type #endif // BOOST_PARAMETER_CAN_USE_MP11 , ::boost::parameter::aux::tag<Tag,T> >::type operator=(T&& x) const { typedef typename ::boost::parameter::aux::tag<Tag,T>::type result; return result(::std::forward<T>(x)); } template <typename Default> inline BOOST_CONSTEXPR typename ::boost::enable_if< #if defined(BOOST_PARAMETER_CAN_USE_MP11) ::boost::mp11::mp_if< ::std::is_scalar<Default> , ::boost::mp11::mp_false , ::boost::mp11::mp_if< ::std::is_same< typename Tag::qualifier , ::boost::parameter::in_reference > , ::boost::mp11::mp_true , ::std::is_same< typename Tag::qualifier , ::boost::parameter::forward_reference > > > #else // !defined(BOOST_PARAMETER_CAN_USE_MP11) typename ::boost::mpl::eval_if< ::boost::is_scalar<Default> , ::boost::mpl::false_ , ::boost::mpl::eval_if< ::boost::is_same< typename Tag::qualifier , ::boost::parameter::in_reference > , ::boost::mpl::true_ , ::boost::mpl::if_< ::boost::is_same< typename Tag::qualifier , ::boost::parameter::forward_reference > , ::boost::mpl::true_ , ::boost::mpl::false_ > > >::type #endif // BOOST_PARAMETER_CAN_USE_MP11 , ::boost::parameter::aux::default_r_<Tag,Default const> >::type operator|(Default const&& d) const { return ::boost::parameter::aux::default_r_<Tag,Default const>( ::std::forward<Default const>(d) ); } template <typename Default> inline BOOST_CONSTEXPR typename ::boost::enable_if< #if defined(BOOST_PARAMETER_CAN_USE_MP11) ::boost::mp11::mp_if< ::std::is_scalar<Default> , ::boost::mp11::mp_false , ::boost::mp11::mp_if< ::std::is_same< typename Tag::qualifier , ::boost::parameter::consume_reference > , ::boost::mp11::mp_true , ::std::is_same< typename Tag::qualifier , ::boost::parameter::forward_reference > > > #else // !defined(BOOST_PARAMETER_CAN_USE_MP11) typename ::boost::mpl::eval_if< ::boost::is_scalar<Default> , ::boost::mpl::false_ , ::boost::mpl::eval_if< ::boost::is_same< typename Tag::qualifier , ::boost::parameter::consume_reference > , ::boost::mpl::true_ , ::boost::mpl::if_< ::boost::is_same< typename Tag::qualifier , ::boost::parameter::forward_reference > , ::boost::mpl::true_ , ::boost::mpl::false_ > > >::type #endif // BOOST_PARAMETER_CAN_USE_MP11 , ::boost::parameter::aux::default_r_<Tag,Default> >::type operator|(Default&& d) const { return ::boost::parameter::aux ::default_r_<Tag,Default>(::std::forward<Default>(d)); } public: // Insurance against ODR violations // Users will need to define their keywords in header files. To // prevent ODR violations, it's important that the keyword used in // every instantiation of a function template is the same object. // We provide a reference to a common instance of each keyword // object and prevent construction by users. static ::boost::parameter::keyword<Tag> const instance; // This interface is deprecated. static ::boost::parameter::keyword<Tag>& get() { return const_cast< ::boost::parameter::keyword<Tag>&>(instance); } }; template <typename Tag> ::boost::parameter::keyword<Tag> const ::boost::parameter ::keyword<Tag>::instance = ::boost::parameter::keyword<Tag>(); }} // namespace boost::parameter #else // !defined(BOOST_PARAMETER_HAS_PERFECT_FORWARDING) #if !defined(BOOST_NO_SFINAE) #include <boost/mpl/bool.hpp> #include <boost/mpl/if.hpp> #include <boost/mpl/eval_if.hpp> #include <boost/core/enable_if.hpp> #include <boost/type_traits/is_same.hpp> #include <boost/type_traits/is_scalar.hpp> #include <boost/type_traits/is_const.hpp> #endif // BOOST_NO_SFINAE namespace boost { namespace parameter { // Instances of unique specializations of keyword<...> serve to // associate arguments with parameter names. For example: // // struct rate_; // parameter names // struct skew_; // // namespace // { // keyword<rate_> rate; // keywords // keyword<skew_> skew; // } // // ... // // f(rate = 1, skew = 2.4); template <typename Tag> struct keyword { typedef Tag tag; inline BOOST_CONSTEXPR keyword() { } template <typename T> #if defined(BOOST_NO_SFINAE) inline typename ::boost::parameter::aux::tag<Tag,T const&>::type #else inline BOOST_CONSTEXPR typename ::boost::lazy_enable_if< typename ::boost::mpl::eval_if< ::boost::is_scalar<T> , ::boost::mpl::true_ , ::boost::mpl::eval_if< ::boost::is_same< typename Tag::qualifier , ::boost::parameter::in_reference > , ::boost::mpl::true_ , ::boost::mpl::if_< ::boost::is_same< typename Tag::qualifier , ::boost::parameter::forward_reference > , ::boost::mpl::true_ , ::boost::mpl::false_ > > >::type , ::boost::parameter::aux::tag<Tag,T const&> >::type #endif // BOOST_NO_SFINAE operator=(T const& x) const { typedef typename ::boost::parameter::aux ::tag<Tag,T const&>::type result; return result(x); } template <typename Default> #if defined(BOOST_NO_SFINAE) inline ::boost::parameter::aux::default_<Tag,Default const> #else inline BOOST_CONSTEXPR typename ::boost::enable_if< typename ::boost::mpl::eval_if< ::boost::is_scalar<Default> , ::boost::mpl::true_ , ::boost::mpl::eval_if< ::boost::is_same< typename Tag::qualifier , ::boost::parameter::in_reference > , ::boost::mpl::true_ , ::boost::mpl::if_< ::boost::is_same< typename Tag::qualifier , ::boost::parameter::forward_reference > , ::boost::mpl::true_ , ::boost::mpl::false_ > > >::type , ::boost::parameter::aux::default_<Tag,Default const> >::type #endif // BOOST_NO_SFINAE operator|(Default const& d) const { return ::boost::parameter::aux::default_<Tag,Default const>(d); } template <typename T> #if defined(BOOST_NO_SFINAE) inline typename ::boost::parameter::aux::tag<Tag,T&>::type #else inline BOOST_CONSTEXPR typename ::boost::lazy_enable_if< typename ::boost::mpl::eval_if< typename ::boost::mpl::if_< ::boost::is_same< typename Tag::qualifier , ::boost::parameter::out_reference > , ::boost::mpl::true_ , ::boost::is_same< typename Tag::qualifier , ::boost::parameter::forward_reference > >::type , ::boost::mpl::if_< ::boost::is_const<T> , ::boost::mpl::false_ , ::boost::mpl::true_ > , ::boost::mpl::false_ >::type , ::boost::parameter::aux::tag<Tag,T&> >::type #endif // BOOST_NO_SFINAE operator=(T& x) const { typedef typename ::boost::parameter::aux ::tag<Tag,T&>::type result; return result(x); } template <typename Default> #if defined(BOOST_NO_SFINAE) inline ::boost::parameter::aux::default_<Tag,Default> #else inline BOOST_CONSTEXPR typename ::boost::enable_if< typename ::boost::mpl::eval_if< typename ::boost::mpl::if_< ::boost::is_same< typename Tag::qualifier , ::boost::parameter::out_reference > , ::boost::mpl::true_ , ::boost::is_same< typename Tag::qualifier , ::boost::parameter::forward_reference > >::type , ::boost::mpl::if_< ::boost::is_const<Default> , ::boost::mpl::false_ , ::boost::mpl::true_ > , ::boost::mpl::false_ >::type , ::boost::parameter::aux::default_<Tag,Default> >::type #endif // BOOST_NO_SFINAE operator|(Default& d) const { return ::boost::parameter::aux::default_<Tag,Default>(d); } template <typename Default> inline BOOST_CONSTEXPR ::boost::parameter::aux::lazy_default<Tag,Default const> operator||(Default const& d) const { return ::boost::parameter::aux ::lazy_default<Tag,Default const>(d); } template <typename Default> inline BOOST_CONSTEXPR ::boost::parameter::aux::lazy_default<Tag,Default> operator||(Default& d) const { return ::boost::parameter::aux::lazy_default<Tag,Default>(d); } public: // Insurance against ODR violations // Users will need to define their keywords in header files. To // prevent ODR violations, it's important that the keyword used in // every instantiation of a function template is the same object. // We provide a reference to a common instance of each keyword // object and prevent construction by users. static ::boost::parameter::keyword<Tag> const instance; // This interface is deprecated. static ::boost::parameter::keyword<Tag>& get() { return const_cast< ::boost::parameter::keyword<Tag>&>(instance); } }; template <typename Tag> ::boost::parameter::keyword<Tag> const ::boost::parameter ::keyword<Tag>::instance = ::boost::parameter::keyword<Tag>(); }} // namespace boost::parameter #endif // BOOST_PARAMETER_HAS_PERFECT_FORWARDING #include <boost/parameter/aux_/name.hpp> #include <boost/preprocessor/stringize.hpp> // Reduces boilerplate required to declare and initialize keywords without // violating ODR. Declares a keyword tag type with the given name in // namespace tag_namespace, and declares and initializes a reference in an // anonymous namespace to a singleton instance of that type. #if defined(BOOST_PARAMETER_CAN_USE_MP11) #define BOOST_PARAMETER_KEYWORD(tag_namespace, name) \ namespace tag_namespace \ { \ struct name \ { \ static BOOST_CONSTEXPR char const* keyword_name() \ { \ return BOOST_PP_STRINGIZE(name); \ } \ using _ = BOOST_PARAMETER_TAG_PLACEHOLDER_TYPE(name); \ using _1 = _; \ BOOST_PARAMETER_TAG_MP11_PLACEHOLDER_BINDING(binding_fn, name); \ BOOST_PARAMETER_TAG_MP11_PLACEHOLDER_VALUE(fn, name); \ using qualifier = ::boost::parameter::forward_reference; \ }; \ } \ namespace \ { \ ::boost::parameter::keyword<tag_namespace::name> const& name \ = ::boost::parameter::keyword<tag_namespace::name>::instance; \ } /**/ #else // !defined(BOOST_PARAMETER_CAN_USE_MP11) #define BOOST_PARAMETER_KEYWORD(tag_namespace, name) \ namespace tag_namespace \ { \ struct name \ { \ static BOOST_CONSTEXPR char const* keyword_name() \ { \ return BOOST_PP_STRINGIZE(name); \ } \ typedef BOOST_PARAMETER_TAG_PLACEHOLDER_TYPE(name) _; \ typedef BOOST_PARAMETER_TAG_PLACEHOLDER_TYPE(name) _1; \ typedef ::boost::parameter::forward_reference qualifier; \ }; \ } \ namespace \ { \ ::boost::parameter::keyword<tag_namespace::name> const& name \ = ::boost::parameter::keyword<tag_namespace::name>::instance; \ } /**/ #endif // BOOST_PARAMETER_CAN_USE_MP11 #endif // include guard