1 2 template<typename _Callable> 3 struct _RangeAdaptor 4 { _RangeAdaptor_RangeAdaptor5 constexpr _RangeAdaptor(const _Callable &) { } 6 }; 7 8 template<typename _Callable> 9 _RangeAdaptor(_Callable) -> _RangeAdaptor<_Callable>; 10 11 template<unsigned _Nm> 12 inline constexpr _RangeAdaptor elements = [] (auto&& __r) {}; 13 14