Created
March 20, 2017 23:39
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| #include <iostream> | |
| #include <string> | |
| #include <reflexpr> | |
| #include <type_traits> | |
| namespace product_type { | |
| namespace meta = std::meta; | |
| template <typename PT> | |
| struct size : meta::get_size<meta::get_data_members_m<reflexpr(PT)>> {}; | |
| template <auto N, typename PT> | |
| constexpr auto get(PT&& pt) { | |
| using Element = meta::get_element_m<meta::get_data_members_m<reflexpr(PT)>, N>; | |
| return pt.*(meta::get_pointer<Element>::value); | |
| } | |
| template <std::size_t N, class PT> | |
| struct element { | |
| using Element = meta::get_element_m<meta::get_data_members_m<reflexpr(PT)>, N>; | |
| // error: __unrefltype operator not applicable to a | |
| // metaobject reflecting a data member | |
| // TODO: why??? | |
| // using type = meta::get_reflected_type_t<Element>; | |
| using type = decltype(std::declval<PT>().*(meta::get_pointer<Element>::value)); | |
| }; | |
| } | |
| struct foo { | |
| int a; | |
| std::string b; | |
| }; | |
| int main() { | |
| foo f{1, "hello"}; | |
| std::cout << "Size of foo: " << product_type::size<foo>::value << "\n"; | |
| std::cout << "2nd member of foo: " << product_type::get<1>(std::move(f)) << "\n"; | |
| using FooBType = product_type::element<1, foo>::type; | |
| std::cout << "Type of second member of foo: " | |
| << std::meta::get_base_name_v<std::meta::get_aliased_m<reflexpr(FooBType)>> << "\n"; | |
| } |
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