diff options
Diffstat (limited to 'lib/function_traits.h')
| -rw-r--r-- | lib/function_traits.h | 36 |
1 files changed, 18 insertions, 18 deletions
diff --git a/lib/function_traits.h b/lib/function_traits.h index 83b8e425..143ed162 100644 --- a/lib/function_traits.h +++ b/lib/function_traits.h @@ -8,7 +8,7 @@ namespace Quotient { namespace _impl { - template <typename AlwaysVoid, typename> + template <typename> struct fn_traits {}; } @@ -21,73 +21,73 @@ namespace _impl { */ template <typename T> struct function_traits - : public _impl::fn_traits<void, std::remove_reference_t<T>> {}; + : public _impl::fn_traits<std::remove_reference_t<T>> {}; // Specialisation for a function template <typename ReturnT, typename... ArgTs> struct function_traits<ReturnT(ArgTs...)> { using return_type = ReturnT; using arg_types = std::tuple<ArgTs...>; - // See also the comment for wrap_in_function() in qt_connection_util.h - using function_type = std::function<ReturnT(ArgTs...)>; }; namespace _impl { - template <typename AlwaysVoid, typename> + template <typename> struct fn_object_traits; // Specialisation for a lambda function template <typename ReturnT, typename ClassT, typename... ArgTs> - struct fn_object_traits<void, ReturnT (ClassT::*)(ArgTs...)> + struct fn_object_traits<ReturnT (ClassT::*)(ArgTs...)> : function_traits<ReturnT(ArgTs...)> {}; // Specialisation for a const lambda function template <typename ReturnT, typename ClassT, typename... ArgTs> - struct fn_object_traits<void, ReturnT (ClassT::*)(ArgTs...) const> + struct fn_object_traits<ReturnT (ClassT::*)(ArgTs...) const> : function_traits<ReturnT(ArgTs...)> {}; // Specialisation for function objects with (non-overloaded) operator() // (this includes non-generic lambdas) template <typename T> - struct fn_traits<decltype(void(&T::operator())), T> - : public fn_object_traits<void, decltype(&T::operator())> {}; + requires requires { &T::operator(); } + struct fn_traits<T> + : public fn_object_traits<decltype(&T::operator())> {}; // Specialisation for a member function in a non-functor class template <typename ReturnT, typename ClassT, typename... ArgTs> - struct fn_traits<void, ReturnT (ClassT::*)(ArgTs...)> + struct fn_traits<ReturnT (ClassT::*)(ArgTs...)> : function_traits<ReturnT(ClassT, ArgTs...)> {}; // Specialisation for a const member function template <typename ReturnT, typename ClassT, typename... ArgTs> - struct fn_traits<void, ReturnT (ClassT::*)(ArgTs...) const> + struct fn_traits<ReturnT (ClassT::*)(ArgTs...) const> : function_traits<ReturnT(const ClassT&, ArgTs...)> {}; // Specialisation for a constref member function template <typename ReturnT, typename ClassT, typename... ArgTs> - struct fn_traits<void, ReturnT (ClassT::*)(ArgTs...) const&> + struct fn_traits<ReturnT (ClassT::*)(ArgTs...) const&> : function_traits<ReturnT(const ClassT&, ArgTs...)> {}; // Specialisation for a prvalue member function template <typename ReturnT, typename ClassT, typename... ArgTs> - struct fn_traits<void, ReturnT (ClassT::*)(ArgTs...) &&> + struct fn_traits<ReturnT (ClassT::*)(ArgTs...) &&> : function_traits<ReturnT(ClassT&&, ArgTs...)> {}; // Specialisation for a pointer-to-member template <typename ReturnT, typename ClassT> - struct fn_traits<void, ReturnT ClassT::*> + struct fn_traits<ReturnT ClassT::*> : function_traits<ReturnT&(ClassT)> {}; // Specialisation for a const pointer-to-member template <typename ReturnT, typename ClassT> - struct fn_traits<void, const ReturnT ClassT::*> + struct fn_traits<const ReturnT ClassT::*> : function_traits<const ReturnT&(ClassT)> {}; } // namespace _impl -template <typename FnT> -using fn_return_t = typename function_traits<FnT>::return_type; - template <typename FnT, int ArgN = 0> using fn_arg_t = std::tuple_element_t<ArgN, typename function_traits<FnT>::arg_types>; +template <typename FnT> +constexpr auto fn_arg_count_v = + std::tuple_size_v<typename function_traits<FnT>::arg_types>; + } // namespace Quotient |