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> constexpr T optional<T>::value_or(U&& v) const&; 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 22 struct Y 23 { 24 int i_; 25 26 constexpr Y(int i) : i_(i) {} 27 }; 28 29 struct X 30 { 31 int i_; 32 33 constexpr X(int i) : i_(i) {} 34 constexpr X(const Y& y) : i_(y.i_) {} 35 constexpr X(Y&& y) : i_(y.i_+1) {} 36 friend constexpr bool operator==(const X& x, const X& y) 37 {return x.i_ == y.i_;} 38 }; 39 40 #endif // _LIBCPP_STD_VER > 11 41 42 int main() 43 { 44 #if _LIBCPP_STD_VER > 11 45 { 46 constexpr optional<X> opt(2); 47 constexpr Y y(3); 48 static_assert(opt.value_or(y) == 2, ""); 49 } 50 { 51 constexpr optional<X> opt(2); 52 static_assert(opt.value_or(Y(3)) == 2, ""); 53 } 54 { 55 constexpr optional<X> opt; 56 constexpr Y y(3); 57 static_assert(opt.value_or(y) == 3, ""); 58 } 59 { 60 constexpr optional<X> opt; 61 static_assert(opt.value_or(Y(3)) == 4, ""); 62 } 63 { 64 const optional<X> opt(2); 65 const Y y(3); 66 assert(opt.value_or(y) == 2); 67 } 68 { 69 const optional<X> opt(2); 70 assert(opt.value_or(Y(3)) == 2); 71 } 72 { 73 const optional<X> opt; 74 const Y y(3); 75 assert(opt.value_or(y) == 3); 76 } 77 { 78 const optional<X> opt; 79 assert(opt.value_or(Y(3)) == 4); 80 } 81 #endif // _LIBCPP_STD_VER > 11 82 } 83
