//----------------------------------------------------------------------------- // boost variant/detail/substitute.hpp header file // See http://www.boost.org for updates, documentation, and revision history. //----------------------------------------------------------------------------- // // Copyright (c) 2003 // Eric Friedman // // 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_VARIANT_DETAIL_SUBSTITUTE_HPP #define BOOST_VARIANT_DETAIL_SUBSTITUTE_HPP #include #include #include #include #include #include #include #include #include namespace boost { namespace detail { namespace variant { /////////////////////////////////////////////////////////////////////////////// // (detail) metafunction substitute // // Substitutes one type for another in the given type expression. // // // primary template // template < typename T, typename Dest, typename Source BOOST_MPL_AUX_LAMBDA_ARITY_PARAM( typename Arity /* = ... (see substitute_fwd.hpp) */ ) > struct substitute { typedef T type; }; // // tag substitution specializations // #define BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL_SUBSTITUTE_TAG(CV_) \ template \ struct substitute< \ CV_ Source \ , Dest \ , Source \ BOOST_MPL_AUX_LAMBDA_ARITY_PARAM(mpl::int_<-1>) \ > \ { \ typedef CV_ Dest type; \ }; \ /**/ BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL_SUBSTITUTE_TAG( BOOST_PP_EMPTY() ) BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL_SUBSTITUTE_TAG(const) BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL_SUBSTITUTE_TAG(volatile) BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL_SUBSTITUTE_TAG(const volatile) #undef BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL_SUBSTITUTE_TAG // // pointer specializations // #define BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL_HANDLE_POINTER(CV_) \ template \ struct substitute< \ T * CV_ \ , Dest \ , Source \ BOOST_MPL_AUX_LAMBDA_ARITY_PARAM(mpl::int_<-1>) \ > \ { \ typedef typename substitute< \ T, Dest, Source \ >::type * CV_ type; \ }; \ /**/ BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL_HANDLE_POINTER( BOOST_PP_EMPTY() ) BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL_HANDLE_POINTER(const) BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL_HANDLE_POINTER(volatile) BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL_HANDLE_POINTER(const volatile) #undef BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL_HANDLE_POINTER // // reference specializations // template struct substitute< T& , Dest , Source BOOST_MPL_AUX_LAMBDA_ARITY_PARAM(mpl::int_<-1>) > { typedef typename substitute< T, Dest, Source >::type & type; }; // // template expression (i.e., F<...>) specializations // template < template class F , typename... Ts , typename Dest , typename Source BOOST_MPL_AUX_LAMBDA_ARITY_PARAM(typename Arity) > struct substitute< F , Dest , Source BOOST_MPL_AUX_LAMBDA_ARITY_PARAM(Arity) > { typedef F::type...> type; }; // // function specializations // template < typename R , typename... A , typename Dest , typename Source > struct substitute< R (*)(A...) , Dest , Source BOOST_MPL_AUX_LAMBDA_ARITY_PARAM(mpl::int_<-1>) > { private: typedef typename substitute< R, Dest, Source >::type r; public: typedef r (*type)(typename substitute< A, Dest, Source >::type...); }; }} // namespace detail::variant } // namespace boost #endif // BOOST_VARIANT_DETAIL_SUBSTITUTE_HPP