From Jason Turner

[optional.relops]

C++17 → C++20 4.3 KB 52 lines
Current Draft | LaTeX Source
Archived: C++17 | C++20
Markdown: C++17 | C++20
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C++ Weekly: Ep 175

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  1. tmp/tmpyrg4501m/{from.md → to.md} +30 -19
tmp/tmpyrg4501m/{from.md → to.md} RENAMED
@@ -2,81 +2,92 @@
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  ``` cpp
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  template<class T, class U> constexpr bool operator==(const optional<T>& x, const optional<U>& y);
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  ```
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- *Requires:* The expression `*x == *y` shall be well-formed and its
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- result shall be convertible to `bool`.
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- [*Note 1*: `T` need not be `EqualityComparable`. — *end note*]
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  *Returns:* If `bool(x) != bool(y)`, `false`; otherwise if
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  `bool(x) == false`, `true`; otherwise `*x == *y`.
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  *Remarks:* Specializations of this function template for which
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- `*x == *y` is a core constant expression shall be constexpr functions.
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  ``` cpp
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  template<class T, class U> constexpr bool operator!=(const optional<T>& x, const optional<U>& y);
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  ```
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- *Requires:* The expression `*x != *y` shall be well-formed and its
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- result shall be convertible to `bool`.
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  *Returns:* If `bool(x) != bool(y)`, `true`; otherwise, if
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  `bool(x) == false`, `false`; otherwise `*x != *y`.
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  *Remarks:* Specializations of this function template for which
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- `*x != *y` is a core constant expression shall be constexpr functions.
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  ``` cpp
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  template<class T, class U> constexpr bool operator<(const optional<T>& x, const optional<U>& y);
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  ```
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- *Requires:* `*x < *y` shall be well-formed and its result shall be
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- convertible to `bool`.
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  *Returns:* If `!y`, `false`; otherwise, if `!x`, `true`; otherwise
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  `*x < *y`.
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  *Remarks:* Specializations of this function template for which `*x < *y`
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- is a core constant expression shall be constexpr functions.
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  ``` cpp
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  template<class T, class U> constexpr bool operator>(const optional<T>& x, const optional<U>& y);
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  ```
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- *Requires:* The expression `*x > *y` shall be well-formed and its result
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- shall be convertible to `bool`.
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  *Returns:* If `!x`, `false`; otherwise, if `!y`, `true`; otherwise
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  `*x > *y`.
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  *Remarks:* Specializations of this function template for which `*x > *y`
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- is a core constant expression shall be constexpr functions.
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  ``` cpp
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  template<class T, class U> constexpr bool operator<=(const optional<T>& x, const optional<U>& y);
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  ```
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- *Requires:* The expression `*x <= *y` shall be well-formed and its
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- result shall be convertible to `bool`.
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  *Returns:* If `!x`, `true`; otherwise, if `!y`, `false`; otherwise
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  `*x <= *y`.
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  *Remarks:* Specializations of this function template for which
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- `*x <= *y` is a core constant expression shall be constexpr functions.
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  ``` cpp
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  template<class T, class U> constexpr bool operator>=(const optional<T>& x, const optional<U>& y);
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  ```
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- *Requires:* The expression `*x >= *y` shall be well-formed and its
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- result shall be convertible to `bool`.
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  *Returns:* If `!y`, `true`; otherwise, if `!x`, `false`; otherwise
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  `*x >= *y`.
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  *Remarks:* Specializations of this function template for which
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- `*x >= *y` is a core constant expression shall be constexpr functions.
 
 
 
 
 
 
 
 
 
 
 
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  ``` cpp
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  template<class T, class U> constexpr bool operator==(const optional<T>& x, const optional<U>& y);
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  ```
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+ *Mandates:* The expression `*x == *y` is well-formed and its result is
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+ convertible to `bool`.
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+ [*Note 1*: `T` need not be *Cpp17EqualityComparable*. — *end note*]
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  *Returns:* If `bool(x) != bool(y)`, `false`; otherwise if
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  `bool(x) == false`, `true`; otherwise `*x == *y`.
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  *Remarks:* Specializations of this function template for which
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+ `*x == *y` is a core constant expression are constexpr functions.
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  ``` cpp
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  template<class T, class U> constexpr bool operator!=(const optional<T>& x, const optional<U>& y);
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  ```
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+ *Mandates:* The expression `*x != *y` is well-formed and its result is
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+ convertible to `bool`.
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  *Returns:* If `bool(x) != bool(y)`, `true`; otherwise, if
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  `bool(x) == false`, `false`; otherwise `*x != *y`.
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  *Remarks:* Specializations of this function template for which
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+ `*x != *y` is a core constant expression are constexpr functions.
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  ``` cpp
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  template<class T, class U> constexpr bool operator<(const optional<T>& x, const optional<U>& y);
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  ```
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+ *Mandates:* `*x < *y` is well-formed and its result is convertible to
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+ `bool`.
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  *Returns:* If `!y`, `false`; otherwise, if `!x`, `true`; otherwise
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  `*x < *y`.
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  *Remarks:* Specializations of this function template for which `*x < *y`
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+ is a core constant expression are constexpr functions.
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  ``` cpp
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  template<class T, class U> constexpr bool operator>(const optional<T>& x, const optional<U>& y);
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  ```
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+ *Mandates:* The expression `*x > *y` is well-formed and its result is
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+ convertible to `bool`.
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  *Returns:* If `!x`, `false`; otherwise, if `!y`, `true`; otherwise
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  `*x > *y`.
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  *Remarks:* Specializations of this function template for which `*x > *y`
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+ is a core constant expression are constexpr functions.
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  ``` cpp
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  template<class T, class U> constexpr bool operator<=(const optional<T>& x, const optional<U>& y);
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  ```
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+ *Mandates:* The expression `*x <= *y` is well-formed and its result is
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+ convertible to `bool`.
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  *Returns:* If `!x`, `true`; otherwise, if `!y`, `false`; otherwise
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  `*x <= *y`.
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  *Remarks:* Specializations of this function template for which
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+ `*x <= *y` is a core constant expression are constexpr functions.
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  ``` cpp
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  template<class T, class U> constexpr bool operator>=(const optional<T>& x, const optional<U>& y);
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  ```
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+ *Mandates:* The expression `*x >= *y` is well-formed and its result is
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+ convertible to `bool`.
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  *Returns:* If `!y`, `true`; otherwise, if `!x`, `false`; otherwise
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  `*x >= *y`.
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  *Remarks:* Specializations of this function template for which
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+ `*x >= *y` is a core constant expression are constexpr functions.
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+
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+ ``` cpp
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+ template<class T, three_way_comparable_with<T> U>
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+ constexpr compare_three_way_result_t<T,U>
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+ operator<=>(const optional<T>& x, const optional<U>& y);
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+ ```
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+
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+ *Returns:* If `x && y`, `*x <=> *y`; otherwise `bool(x) <=> bool(y)`.
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+
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+ *Remarks:* Specializations of this function template for which
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+ `*x <=> *y` is a core constant expression are constexpr functions.
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