1 //===----------------------------------------------------------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is dual licensed under the MIT and the University of Illinois Open 6 // Source Licenses. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 10 // <optional> 11 12 // template <class U> T optional<T>::value_or(U&& v) &&; 13 14 #include <experimental/optional> 15 #include <type_traits> 16 #include <cassert> 17 18 #if _LIBCPP_STD_VER > 11 19 20 using std::experimental::optional; 21 using std::experimental::in_place_t; 22 using std::experimental::in_place; 23 24 struct Y 25 { 26 int i_; 27 28 Y(int i) : i_(i) {} 29 }; 30 31 struct X 32 { 33 int i_; 34 35 X(int i) : i_(i) {} 36 X(X&& x) : i_(x.i_) {x.i_ = 0;} 37 X(const Y& y) : i_(y.i_) {} 38 X(Y&& y) : i_(y.i_+1) {} 39 friend constexpr bool operator==(const X& x, const X& y) 40 {return x.i_ == y.i_;} 41 }; 42 43 #endif // _LIBCPP_STD_VER > 11 44 45 int main() 46 { 47 #if _LIBCPP_STD_VER > 11 48 { 49 optional<X> opt(in_place, 2); 50 Y y(3); 51 assert(std::move(opt).value_or(y) == 2); 52 assert(*opt == 0); 53 } 54 { 55 optional<X> opt(in_place, 2); 56 assert(std::move(opt).value_or(Y(3)) == 2); 57 assert(*opt == 0); 58 } 59 { 60 optional<X> opt; 61 Y y(3); 62 assert(std::move(opt).value_or(y) == 3); 63 assert(!opt); 64 } 65 { 66 optional<X> opt; 67 assert(std::move(opt).value_or(Y(3)) == 4); 68 assert(!opt); 69 } 70 #endif // _LIBCPP_STD_VER > 11 71 } 72
