From Jason Turner

[optional.observe]

C++17 → C++20 2.5 KB 30 lines
Current Draft | LaTeX Source
Archived: C++17 | C++20
Markdown: C++17 | C++20
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  1. tmp/tmp1sc6a728/{from.md → to.md} +13 -13
tmp/tmp1sc6a728/{from.md → to.md} RENAMED
@@ -3,55 +3,55 @@
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  ``` cpp
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  constexpr const T* operator->() const;
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  constexpr T* operator->();
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  ```
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- *Requires:* `*this` contains a value.
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  *Returns:* `val`.
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  *Throws:* Nothing.
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- *Remarks:* These functions shall be constexpr functions.
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  ``` cpp
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  constexpr const T& operator*() const&;
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  constexpr T& operator*() &;
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  ```
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- *Requires:* `*this` contains a value.
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  *Returns:* `*val`.
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  *Throws:* Nothing.
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- *Remarks:* These functions shall be constexpr functions.
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  ``` cpp
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  constexpr T&& operator*() &&;
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  constexpr const T&& operator*() const&&;
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  ```
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- *Requires:* `*this` contains a value.
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  *Effects:* Equivalent to: `return std::move(*val);`
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  ``` cpp
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  constexpr explicit operator bool() const noexcept;
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  ```
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  *Returns:* `true` if and only if `*this` contains a value.
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- *Remarks:* This function shall be a constexpr function.
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  ``` cpp
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  constexpr bool has_value() const noexcept;
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  ```
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  *Returns:* `true` if and only if `*this` contains a value.
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- *Remarks:* This function shall be a constexpr function.
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  ``` cpp
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  constexpr const T& value() const&;
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  constexpr T& value() &;
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  ```
@@ -75,27 +75,27 @@ return bool(*this) ? std::move(*val) : throw bad_optional_access();
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  ``` cpp
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  template<class U> constexpr T value_or(U&& v) const&;
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  ```
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  *Effects:* Equivalent to:
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  ``` cpp
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  return bool(*this) ? **this : static_cast<T>(std::forward<U>(v));
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  ```
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- *Remarks:* If `is_copy_constructible_v<T> && is_convertible_v<U&&, T>`
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- is `false`, the program is ill-formed.
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-
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  ``` cpp
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  template<class U> constexpr T value_or(U&& v) &&;
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  ```
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  *Effects:* Equivalent to:
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  ``` cpp
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  return bool(*this) ? std::move(**this) : static_cast<T>(std::forward<U>(v));
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  ```
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- *Remarks:* If `is_move_constructible_v<T> && is_convertible_v<U&&, T>`
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- is `false`, the program is ill-formed.
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-
 
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  ``` cpp
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  constexpr const T* operator->() const;
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  constexpr T* operator->();
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  ```
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+ *Preconditions:* `*this` contains a value.
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  *Returns:* `val`.
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  *Throws:* Nothing.
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+ *Remarks:* These functions are constexpr functions.
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  ``` cpp
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  constexpr const T& operator*() const&;
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  constexpr T& operator*() &;
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  ```
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+ *Preconditions:* `*this` contains a value.
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  *Returns:* `*val`.
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  *Throws:* Nothing.
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+ *Remarks:* These functions are constexpr functions.
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  ``` cpp
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  constexpr T&& operator*() &&;
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  constexpr const T&& operator*() const&&;
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  ```
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+ *Preconditions:* `*this` contains a value.
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  *Effects:* Equivalent to: `return std::move(*val);`
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  ``` cpp
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  constexpr explicit operator bool() const noexcept;
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  ```
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  *Returns:* `true` if and only if `*this` contains a value.
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+ *Remarks:* This function is a constexpr function.
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  ``` cpp
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  constexpr bool has_value() const noexcept;
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  ```
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  *Returns:* `true` if and only if `*this` contains a value.
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+ *Remarks:* This function is a constexpr function.
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  ``` cpp
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  constexpr const T& value() const&;
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  constexpr T& value() &;
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  ```
 
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  ``` cpp
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  template<class U> constexpr T value_or(U&& v) const&;
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  ```
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+ *Mandates:* `is_copy_constructible_v<T> && is_convertible_v<U&&, T>` is
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+ `true`.
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+
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  *Effects:* Equivalent to:
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  ``` cpp
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  return bool(*this) ? **this : static_cast<T>(std::forward<U>(v));
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  ```
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  ``` cpp
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  template<class U> constexpr T value_or(U&& v) &&;
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  ```
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+ *Mandates:* `is_move_constructible_v<T> && is_convertible_v<U&&, T>` is
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+ `true`.
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+
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  *Effects:* Equivalent to:
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  ``` cpp
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  return bool(*this) ? std::move(**this) : static_cast<T>(std::forward<U>(v));
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  ```
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