Refactor to add symmetry with member object

boostorg · Jun 11, 2019 · daa802d · daa802d
1 parent 24c5a6e
commit daa802d
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Showing 2 changed files with 18 additions and 10 deletions.
diff --git a/include/boost/hana/detail/struct_macros.hpp b/include/boost/hana/detail/struct_macros.hpp
@@ -36,13 +36,17 @@ Distributed under the Boost Software License, Version 1.0.
 BOOST_HANA_NAMESPACE_BEGIN namespace struct_detail {
     template <typename Memptr, Memptr ptr>
     struct member_ptr {
-        template <typename T, typename = std::enable_if_t<!std::is_member_function_pointer_v<Memptr>>>
-        constexpr decltype(auto) operator()(T&& t) const
+        template <typename Memptr2, typename T, std::enable_if_t<std::is_member_object_pointer_v<Memptr2>, int> = 0>
+        constexpr decltype(auto) dispatch(T && t) const
         { return static_cast<T&&>(t).*ptr; }
 
-        template <typename T, typename ... Args, typename = std::enable_if_t<std::is_member_function_pointer_v<Memptr>>>
-        constexpr decltype(auto) operator()(T&& t, Args&&... args) const
-        { return (static_cast<T&&>(t).*ptr)(std::forward<Args>(args)...); }
+        template <typename Memptr2, typename T, std::enable_if_t<std::is_member_function_pointer_v<Memptr2>, int> = 0>
+        constexpr decltype(auto) dispatch(T && t) const
+        { return [&](auto ... args) { return static_cast<T&&>(t).*ptr(args); }; }
+
+        template <typename T>
+        constexpr decltype(auto) operator()(T && t) const
+        { return dispatch<Memptr>(t); }
     };
 
     constexpr std::size_t strlen(char const* s) {

diff --git a/include/boost/hana/detail/struct_macros.hpp.erb b/include/boost/hana/detail/struct_macros.hpp.erb
@@ -54,13 +54,17 @@ Distributed under the Boost Software License, Version 1.0.
 BOOST_HANA_NAMESPACE_BEGIN namespace struct_detail {
     template <typename Memptr, Memptr ptr>
     struct member_ptr {
-        template <typename T, typename = std::enable_if_t<!std::is_member_function_pointer_v<Memptr>>>
-        constexpr decltype(auto) operator()(T&& t) const
+        template <typename Memptr2, typename T, std::enable_if_t<std::is_member_object_pointer_v<Memptr2>, int> = 0>
+        constexpr decltype(auto) dispatch(T && t) const
         { return static_cast<T&&>(t).*ptr; }
 
-        template <typename T, typename ... Args, typename = std::enable_if_t<std::is_member_function_pointer_v<Memptr>>>
-        constexpr decltype(auto) operator()(T&& t, Args&&... args) const
-        { return (static_cast<T&&>(t).*ptr)(std::forward<Args>(args)...); }
+        template <typename Memptr2, typename T, std::enable_if_t<std::is_member_function_pointer_v<Memptr2>, int> = 0>
+        constexpr decltype(auto) dispatch(T && t) const
+        { return [&](auto ... args) { return static_cast<T&&>(t).*ptr(args); }; }
+
+        template <typename T>
+        constexpr decltype(auto) operator()(T && t) const
+        { return dispatch<Memptr>(t); }
     };
 
     constexpr std::size_t strlen(char const* s) {