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/* Copyright (C) 2019 Povilas Kanapickas <povilas@radix.lt>
This file is part of cppreference-doc
This work is licensed under the Creative Commons Attribution-ShareAlike 3.0
Unported License. To view a copy of this license, visit
http://creativecommons.org/licenses/by-sa/3.0/ or send a letter to Creative
Commons, 444 Castro Street, Suite 900, Mountain View, California, 94041, USA.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3 or
any later version published by the Free Software Foundation; with no
Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
*/
#ifndef CPPREFERENCE_OPTIONAL_H
#define CPPREFERENCE_OPTIONAL_H
#if CPPREFERENCE_STDVER >= 2017
#include <functional> // hash
#include <utility> // in_place_t, ...
#include <type_traits> // decay_t
#include <exception> // exception
namespace std {
struct nullopt_t {};
inline constexpr nullopt_t nullopt;
class bad_optional_access : public exception {
public:
~bad_optional_access() override;
const char * what() const override;
};
template<class T>
class optional {
public:
using value_type = T;
constexpr optional();
constexpr optional(std::nullopt_t);
constexpr optional(const optional& other);
constexpr optional(optional&& other);
template <class U>
optional(const optional<U>& other);
template<class U>
optional(optional<U>&& other);
template<class... Args>
constexpr explicit optional(in_place_t, Args&&... args);
template<class U, class... Args>
constexpr explicit optional(in_place_t,
initializer_list<U> ilist,
Args&&... args);
template<class U = value_type>
constexpr optional(U&& value);
~optional();
optional& operator=(std::nullopt_t);
constexpr optional& operator=(const optional& other);
constexpr optional& operator=(optional&& other);
template<class U = T>
optional& operator=(U&& value);
template<class U>
optional& operator=(const optional<U>& other);
template<class U>
optional& operator=(optional<U>&& other);
constexpr const T* operator->() const;
constexpr T* operator->();
constexpr const T& operator*() const&;
constexpr T& operator*() &;
constexpr const T&& operator*() const&&;
constexpr T&& operator*() &&;
constexpr explicit operator bool() const;
constexpr bool has_value() const;
constexpr T& value() &;
constexpr const T & value() const &;
constexpr T&& value() &&;
constexpr const T&& value() const &&;
template< class U >
constexpr T value_or(U&& default_value) const&;
template< class U >
constexpr T value_or(U&& default_value) &&;
void swap(optional& other);
void reset();
template<class... Args>
T& emplace(Args&&... args);
template<class U, class... Args>
T& emplace(initializer_list<U> ilist, Args&&... args);
};
template<class T, class U>
constexpr bool operator==(const optional<T>& lhs, const optional<U>& rhs);
template<class T, class U>
constexpr bool operator!=(const optional<T>& lhs, const optional<U>& rhs);
template<class T, class U>
constexpr bool operator<(const optional<T>& lhs, const optional<U>& rhs);
template<class T, class U>
constexpr bool operator<=(const optional<T>& lhs, const optional<U>& rhs);
template<class T, class U>
constexpr bool operator>(const optional<T>& lhs, const optional<U>& rhs);
template<class T, class U>
constexpr bool operator>=(const optional<T>& lhs, const optional<U>& rhs);
template<class T>
constexpr bool operator==(const optional<T>& opt, nullopt_t);
template<class T>
constexpr bool operator==(nullopt_t, const optional<T>& opt);
template<class T>
constexpr bool operator!=(const optional<T>& opt, nullopt_t);
template<class T>
constexpr bool operator!=(nullopt_t, const optional<T>& opt);
template<class T>
constexpr bool operator<(const optional<T>& opt, nullopt_t);
template<class T>
constexpr bool operator<(nullopt_t, const optional<T>& opt);
template<class T>
constexpr bool operator<=(const optional<T>& opt, nullopt_t);
template<class T>
constexpr bool operator<=(nullopt_t, const optional<T>& opt);
template<class T>
constexpr bool operator>(const optional<T>& opt, nullopt_t);
template<class T>
constexpr bool operator>(nullopt_t, const optional<T>& opt);
template<class T>
constexpr bool operator>=(const optional<T>& opt, nullopt_t);
template<class T>
constexpr bool operator>=(nullopt_t, const optional<T>& opt);
template<class T, class U>
constexpr bool operator==(const optional<T>& opt, const U& value);
template<class T, class U>
constexpr bool operator==(const T& value, const optional<U>& opt);
template<class T, class U>
constexpr bool operator!=(const optional<T>& opt, const U& value);
template<class T, class U>
constexpr bool operator!=(const T& value, const optional<U>& opt);
template<class T, class U>
constexpr bool operator<(const optional<T>& opt, const U& value);
template<class T, class U>
constexpr bool operator<(const T& value, const optional<U>& opt);
template<class T, class U>
constexpr bool operator<=(const optional<T>& opt, const U& value);
template<class T, class U>
constexpr bool operator<=(const T& value, const optional<U>& opt);
template<class T, class U>
constexpr bool operator>(const optional<T>& opt, const U& value);
template<class T, class U>
constexpr bool operator>(const T& value, const optional<U>& opt);
template<class T, class U>
constexpr bool operator>=(const optional<T>& opt, const U& value);
template<class T, class U>
constexpr bool operator>=(const T& value, const optional<U>& opt);
template<class T>
constexpr optional<decay_t<T>> make_optional(T&& value);
template<class T, class... Args>
constexpr optional<T> make_optional(Args&&... args);
template<class T, class U, class... Args>
constexpr optional<T> make_optional(initializer_list<U> il, Args&&... args);
template<class T>
void swap(optional<T>& lhs, optional<T>& rhs);
template<class T>
struct hash<std::optional<T>> {};
} // namespace std
#endif // CPPREFERENCE_STDVER >= 2017
#endif // CPPREFERENCE_OPTIONAL_H