boost/proto/detail/decltype.hpp
/////////////////////////////////////////////////////////////////////////////// /// \file decltype.hpp /// Contains definition the BOOST_PROTO_DECLTYPE_() macro and assorted helpers // // Copyright 2008 Eric Niebler. 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_PROTO_DETAIL_DECLTYPE_HPP_EAN_04_04_2008 #define BOOST_PROTO_DETAIL_DECLTYPE_HPP_EAN_04_04_2008 #include <boost/config.hpp> #include <boost/detail/workaround.hpp> #include <boost/get_pointer.hpp> #include <boost/preprocessor/cat.hpp> #include <boost/preprocessor/repetition/enum_params.hpp> #include <boost/preprocessor/repetition/enum_trailing_params.hpp> #include <boost/preprocessor/repetition/enum_binary_params.hpp> #include <boost/preprocessor/repetition/repeat.hpp> #include <boost/preprocessor/repetition/repeat_from_to.hpp> #include <boost/preprocessor/iteration/local.hpp> #include <boost/mpl/if.hpp> #include <boost/mpl/eval_if.hpp> #include <boost/mpl/identity.hpp> #include <boost/type_traits/is_class.hpp> #include <boost/type_traits/remove_reference.hpp> #include <boost/type_traits/is_pointer.hpp> #include <boost/type_traits/is_function.hpp> #include <boost/type_traits/is_member_object_pointer.hpp> #include <boost/type_traits/add_const.hpp> #include <boost/type_traits/add_reference.hpp> #include <boost/typeof/typeof.hpp> #include <boost/utility/addressof.hpp> #include <boost/utility/result_of.hpp> #include <boost/utility/enable_if.hpp> #include <boost/proto/proto_fwd.hpp> #include <boost/proto/detail/any.hpp> #if defined(_MSC_VER) # pragma warning(push) # pragma warning(disable : 4714) // function 'xxx' marked as __forceinline not inlined #endif // We're STILL using Boost.Typeof on MSVC even for msvc-11.0 because of this bug: // https://connect.microsoft.com/VisualStudio/feedback/details/765392/decltype-of-a-pointer-to-member-operator-gets-ref-qualification-wrong #if !defined(BOOST_NO_CXX11_DECLTYPE) && !BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1700)) # define BOOST_PROTO_DECLTYPE_(EXPR, TYPE) typedef decltype((EXPR)) TYPE; #else # define BOOST_PROTO_DECLTYPE_NESTED_TYPEDEF_TPL_(NESTED, EXPR) \ BOOST_TYPEOF_NESTED_TYPEDEF_TPL(BOOST_PP_CAT(nested_and_hidden_, NESTED), EXPR) \ static int const BOOST_PP_CAT(sz, NESTED) = sizeof(boost::proto::detail::check_reference(EXPR));\ struct NESTED \ : boost::mpl::if_c< \ 1 == BOOST_PP_CAT(sz, NESTED) \ , typename BOOST_PP_CAT(nested_and_hidden_, NESTED)::type & \ , typename BOOST_PP_CAT(nested_and_hidden_, NESTED)::type \ > \ {}; # define BOOST_PROTO_DECLTYPE_(EXPR, TYPE) \ BOOST_PROTO_DECLTYPE_NESTED_TYPEDEF_TPL_(BOOST_PP_CAT(nested_, TYPE), (EXPR)) \ typedef typename BOOST_PP_CAT(nested_, TYPE)::type TYPE; #endif namespace boost { namespace proto { namespace detail { //////////////////////////////////////////////////////////////////////////////////////////// template<typename T> struct as_mutable { typedef T &type; }; template<typename T> struct as_mutable<T &> { typedef T &type; }; template<typename T> struct as_mutable<T const &> { typedef T &type; }; //////////////////////////////////////////////////////////////////////////////////////////// template<typename T> T make(); //////////////////////////////////////////////////////////////////////////////////////////// template<typename T> typename as_mutable<T>::type make_mutable(); //////////////////////////////////////////////////////////////////////////////////////////// template<typename T> struct subscript_wrapper : T { using T::operator[]; #if BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1500)) any operator[](any const volatile &) const volatile; #else any operator[](any const &) const volatile; #endif }; //////////////////////////////////////////////////////////////////////////////////////////// template<typename T> struct as_subscriptable { typedef typename mpl::if_c< is_class<T>::value , subscript_wrapper<T> , T >::type type; }; template<typename T> struct as_subscriptable<T const> { typedef typename mpl::if_c< is_class<T>::value , subscript_wrapper<T> const , T const >::type type; }; template<typename T> struct as_subscriptable<T &> { typedef typename mpl::if_c< is_class<T>::value , subscript_wrapper<T> & , T & >::type type; }; template<typename T> struct as_subscriptable<T const &> { typedef typename mpl::if_c< is_class<T>::value , subscript_wrapper<T> const & , T const & >::type type; }; //////////////////////////////////////////////////////////////////////////////////////////// template<typename T> typename as_subscriptable<T>::type make_subscriptable(); //////////////////////////////////////////////////////////////////////////////////////////// template<typename T> char check_reference(T &); template<typename T> char (&check_reference(T const &))[2]; namespace has_get_pointerns { using boost::get_pointer; void *(&get_pointer(...))[2]; //////////////////////////////////////////////////////////////////////////////////////////// template<typename T> struct has_get_pointer { static const bool value = sizeof(void *) == sizeof(get_pointer(make<T &>())); typedef mpl::bool_<value> type; }; } using has_get_pointerns::has_get_pointer; //////////////////////////////////////////////////////////////////////////////////////////// template<typename T> struct class_member_traits; template<typename T, typename U> struct class_member_traits<T U::*> { typedef U class_type; typedef T result_type; }; // Other specializations are generated by the preprocessor #include <boost/proto/detail/class_member_traits.hpp> //////////////////////////////////////////////////////////////////////////////////////////// template<typename T> T &lvalue(T &t) { return t; } template<typename T> T const &lvalue(T const &t) { return t; } //////////////////////////////////////////////////////////////////////////////////////////// template<typename U, typename V, typename T> U *proto_get_pointer(T &t, V *, U *) { return boost::addressof(t); } template<typename U, typename V, typename T> U const *proto_get_pointer(T &t, V *, U const *) { return boost::addressof(t); } template<typename U, typename V, typename T> V *proto_get_pointer(T &t, V *, ...) { return get_pointer(t); } //////////////////////////////////////////////////////////////////////////////////////////// #define BOOST_PROTO_USE_GET_POINTER() \ using namespace boost::proto::detail::get_pointerns \ /**/ #define BOOST_PROTO_GET_POINTER(Type, Obj) \ boost::proto::detail::proto_get_pointer<Type>( \ boost::proto::detail::lvalue(Obj) \ , (true ? 0 : get_pointer(Obj)) \ , (true ? 0 : boost::addressof(boost::proto::detail::lvalue(Obj))) \ ) \ /**/ //////////////////////////////////////////////////////////////////////////////////////////// namespace get_pointerns { using boost::get_pointer; template<typename T> typename disable_if_c<has_get_pointer<T>::value, T *>::type get_pointer(T &t) { return boost::addressof(t); } template<typename T> typename disable_if_c<has_get_pointer<T>::value, T const *>::type get_pointer(T const &t) { return boost::addressof(t); } char test_ptr_to_const(void *); char (&test_ptr_to_const(void const *))[2]; template<typename U> char test_V_is_a_U(U *); template<typename U> char test_V_is_a_U(U const *); template<typename U> char (&test_V_is_a_U(...))[2]; //////////////////////////////////////////////////////////////////////////////////////////// // result_of_ is a wrapper around boost::result_of that also handles "invocations" of // member object pointers. template<typename T, typename Void = void> struct result_of_ : BOOST_PROTO_RESULT_OF<T> {}; template<typename T, typename U, typename V> struct result_of_<T U::*(V), typename enable_if_c<is_member_object_pointer<T U::*>::value>::type> { static const bool is_V_a_smart_ptr = 2 == sizeof(test_V_is_a_U<U>(&lvalue(make<V>()))); static const bool is_ptr_to_const = 2 == sizeof(test_ptr_to_const(BOOST_PROTO_GET_POINTER(U, make<V>()))); // If V is not a U, then it is a (smart) pointer and we can always return an lvalue. // Otherwise, we can only return an lvalue if we are given one. typedef typename mpl::eval_if_c< (is_V_a_smart_ptr || is_reference<V>::value) , mpl::eval_if_c< is_ptr_to_const , add_reference<typename add_const<T>::type> , add_reference<T> > , mpl::identity<T> >::type type; }; //////////////////////////////////////////////////////////////////////////////////////////// template< typename T , typename U , bool IsMemPtr = is_member_object_pointer< typename remove_reference<U>::type >::value > struct mem_ptr_fun { BOOST_PROTO_DECLTYPE_( proto::detail::make_mutable<T>() ->* proto::detail::make<U>() , result_type ) result_type operator()( typename add_reference<typename add_const<T>::type>::type t , typename add_reference<typename add_const<U>::type>::type u ) const { return t ->* u; } }; //////////////////////////////////////////////////////////////////////////////////////////// template<typename T, typename U> struct mem_ptr_fun<T, U, true> { typedef typename class_member_traits< typename uncvref<U>::type >::class_type V; BOOST_PROTO_DECLTYPE_( BOOST_PROTO_GET_POINTER(V, proto::detail::make_mutable<T>()) ->* proto::detail::make<U>() , result_type ) result_type operator()( typename add_reference<typename add_const<T>::type>::type t , U u ) const { return BOOST_PROTO_GET_POINTER(V, t) ->* u; } }; } using get_pointerns::result_of_; using get_pointerns::mem_ptr_fun; //////////////////////////////////////////////////////////////////////////////////////////// template<typename A0, typename A1> struct comma_result { BOOST_PROTO_DECLTYPE_((proto::detail::make<A0>(), proto::detail::make<A1>()), type) }; template<typename A0> struct comma_result<A0, void> { typedef void type; }; template<typename A1> struct comma_result<void, A1> { typedef A1 type; }; template<> struct comma_result<void, void> { typedef void type; }; //////////////////////////////////////////////////////////////////////////////////////////// // normalize a function type for use with boost::result_of template<typename T, typename U = T> struct result_of_fixup : mpl::if_c<is_function<T>::value, T *, U> {}; template<typename T, typename U> struct result_of_fixup<T &, U> : result_of_fixup<T, T> {}; template<typename T, typename U> struct result_of_fixup<T const &, U> : result_of_fixup<T, T> {}; template<typename T, typename U> struct result_of_fixup<T *, U> : result_of_fixup<T, U> {}; template<typename R, typename T, typename U> struct result_of_fixup<R T::*, U> { typedef R T::*type; }; template<typename T, typename U> struct result_of_fixup<T const, U> : result_of_fixup<T, U> {}; //// Tests for result_of_fixup //struct bar {}; //BOOST_MPL_ASSERT((is_same<bar, result_of_fixup<bar>::type>)); //BOOST_MPL_ASSERT((is_same<bar const, result_of_fixup<bar const>::type>)); //BOOST_MPL_ASSERT((is_same<bar, result_of_fixup<bar &>::type>)); //BOOST_MPL_ASSERT((is_same<bar const, result_of_fixup<bar const &>::type>)); //BOOST_MPL_ASSERT((is_same<void(*)(), result_of_fixup<void(*)()>::type>)); //BOOST_MPL_ASSERT((is_same<void(*)(), result_of_fixup<void(* const)()>::type>)); //BOOST_MPL_ASSERT((is_same<void(*)(), result_of_fixup<void(* const &)()>::type>)); //BOOST_MPL_ASSERT((is_same<void(*)(), result_of_fixup<void(&)()>::type>)); template<typename T, typename PMF> struct memfun { typedef typename uncvref<PMF>::type pmf_type; typedef typename class_member_traits<pmf_type>::class_type V; typedef typename class_member_traits<pmf_type>::result_type result_type; memfun(T t, pmf_type p) : obj(t) , pmf(p) {} result_type operator()() const { BOOST_PROTO_USE_GET_POINTER(); return (BOOST_PROTO_GET_POINTER(V, obj) ->* pmf)(); } // Other overloads generated by the preprocessor #include <boost/proto/detail/memfun_funop.hpp> private: T obj; pmf_type pmf; }; } // namespace detail }} #if defined(_MSC_VER) # pragma warning(pop) #endif #endif