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Initial support for references

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This commit is contained in:
Simon Brand
2017-12-13 16:03:01 +00:00
parent e589ae4321
commit bdaa41ce8c
1 changed files with 2253 additions and 1430 deletions
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883
tl/optional.hpp
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@ -176,8 +176,8 @@
using disable_if_ret_void = enable_if_t<!returns_void<T &&, U...>::value>;
template <class T, class U>
using enable_forward_value = detail::enable_if_t<
std::is_constructible<T, U &&>::value &&
using enable_forward_value =
detail::enable_if_t<std::is_constructible<T, U &&>::value &&
!std::is_same<detail::decay_t<U>, in_place_t>::value &&
!std::is_same<optional<T>, detail::decay_t<U>>::value>;
@ -221,8 +221,7 @@
// TODO make a version which works with MSVC
template <class T, class U = T> struct is_swappable : std::true_type {};
template <class T, class U = T>
struct is_nothrow_swappable : std::true_type {};
template <class T, class U = T> struct is_nothrow_swappable : std::true_type {};
#else
// https://stackoverflow.com/questions/26744589/what-is-a-proper-way-to-implement-is-swappable-to-test-for-the-swappable-concept
namespace swap_adl_tests {
@ -250,8 +249,7 @@
struct is_std_swap_noexcept
: std::integral_constant<bool,
std::is_nothrow_move_constructible<T>::value &&
std::is_nothrow_move_assignable<T>::value> {
};
std::is_nothrow_move_assignable<T>::value> {};
template <class T, std::size_t N>
struct is_std_swap_noexcept<T[N]> : is_std_swap_noexcept<T> {};
@ -284,11 +282,12 @@
: std::integral_constant<
bool,
is_swappable<T, U>::value &&
((decltype(detail::swap_adl_tests::uses_std<T, U>(0))::value &&
detail::swap_adl_tests::is_std_swap_noexcept<T>::value) ||
(!decltype(detail::swap_adl_tests::uses_std<T, U>(0))::value
&&detail::swap_adl_tests::is_adl_swap_noexcept<
T, U>::value))> {};
((decltype(detail::swap_adl_tests::uses_std<T, U>(0))::value
&&detail::swap_adl_tests::is_std_swap_noexcept<T>::value) ||
(!decltype(detail::swap_adl_tests::uses_std<T, U>(0))::value &&
detail::swap_adl_tests::is_adl_swap_noexcept<T,
U>::value))> {
};
#endif
// The storage base manages the actual storage, and correctly propagates
@ -341,8 +340,7 @@
// This base class provides some handy member functions which can be used in
// further derived classes
template <class T>
struct optional_operations_base : optional_storage_base<T> {
template <class T> struct optional_operations_base : optional_storage_base<T> {
using optional_storage_base<T>::optional_storage_base;
void hard_reset() noexcept {
@ -419,8 +417,7 @@
#else
template <class T, bool = false> struct optional_move_base;
#endif
template <class T>
struct optional_move_base<T, false> : optional_copy_base<T> {
template <class T> struct optional_move_base<T, false> : optional_copy_base<T> {
using optional_copy_base<T>::optional_copy_base;
optional_move_base() = default;
@ -631,9 +628,6 @@
private detail::optional_delete_assign_base<T> {
using base = detail::optional_move_assign_base<T>;
static_assert(
!std::is_reference<T>::value,
"instantiation of optional with a reference type is ill-formed");
static_assert(!std::is_same<T, in_place_t>::value,
"instantiation of optional with in_place_t is ill-formed");
static_assert(!std::is_same<detail::decay_t<T>, nullopt_t>::value,
@ -723,8 +717,7 @@
/// \group and_then
/// \synopsis template <class F>\nconstexpr auto and_then(F &&f) &&;
template <class F>
TL_OPTIONAL_11_CONSTEXPR detail::invoke_result_t<F, T &&>
and_then(F &&f) && {
TL_OPTIONAL_11_CONSTEXPR detail::invoke_result_t<F, T &&> and_then(F &&f) && {
using result = detail::invoke_result_t<F, T &&>;
static_assert(detail::is_optional<result>::value,
"F must return an optional");
@ -1100,8 +1093,7 @@
/// optional(in_place_t, Args&&... args);
template <class... Args>
constexpr explicit optional(
detail::enable_if_t<std::is_constructible<T, Args...>::value,
in_place_t>,
detail::enable_if_t<std::is_constructible<T, Args...>::value, in_place_t>,
Args &&... args)
: base(in_place, std::forward<Args>(args)...) {}
@ -1134,9 +1126,9 @@
/// Converting copy constructor.
/// \synopsis template <class U> optional(const optional<U> &rhs);
template <class U, detail::enable_from_other<T, U, const U &> * = nullptr,
detail::enable_if_t<std::is_convertible<const U &, T>::value> * =
nullptr>
template <
class U, detail::enable_from_other<T, U, const U &> * = nullptr,
detail::enable_if_t<std::is_convertible<const U &, T>::value> * = nullptr>
optional(const optional<U> &rhs) {
this->construct(*rhs);
}
@ -1329,9 +1321,7 @@
#ifndef TL_OPTIONAL_NO_CONSTRR
/// \exclude
constexpr const T &&operator*() const && {
return std::move(this->m_value);
}
constexpr const T &&operator*() const && { return std::move(this->m_value); }
#endif
/// \returns whether or not the optional has a value
@ -1576,8 +1566,7 @@
/// \synopsis template <class T>\nvoid swap(optional<T> &lhs, optional<T>
/// &rhs);
template <class T,
detail::enable_if_t<std::is_move_constructible<T>::value> * =
nullptr,
detail::enable_if_t<std::is_move_constructible<T>::value> * = nullptr,
detail::enable_if_t<detail::is_swappable<T>::value> * = nullptr>
void swap(optional<T> &lhs,
optional<T> &rhs) noexcept(noexcept(lhs.swap(rhs))) {
@ -1602,6 +1591,840 @@
template <class T> optional(T)->optional<T>;
#endif
/// An optional object is an object that contains the storage for another
/// object and manages the lifetime of this contained object, if any. The
/// contained object may be initialized after the optional object has been
/// initialized, and may be destroyed before the optional object has been
/// destroyed. The initialization state of the contained object is tracked by
/// the optional object.
template <class T> class optional<T &> {
public:
// The different versions for C++14 and 11 are needed because deduced return
// types are not SFINAE-safe. This provides better support for things like
// generic lambdas. C.f.
// http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2017/p0826r0.html
#if defined(TL_OPTIONAL_CXX14) && !defined(TL_OPTIONAL_GCC49) && \
!defined(TL_OPTIONAL_GCC54)
/// \group and_then
/// Carries out some operation which returns an optional on the stored
/// object if there is one. \requires `std::invoke(std::forward<F>(f),
/// value())` returns a `std::optional<U>` for some `U`. \returns Let `U` be
/// the result of `std::invoke(std::forward<F>(f), value())`. Returns a
/// `std::optional<U>`. The return value is empty if `*this` is empty,
/// otherwise the return value of `std::invoke(std::forward<F>(f), value())`
/// is returned.
/// \group and_then
/// \synopsis template <class F>\nconstexpr auto and_then(F &&f) &;
template <class F> TL_OPTIONAL_11_CONSTEXPR auto and_then(F &&f) & {
using result = detail::invoke_result_t<F, T &>;
static_assert(detail::is_optional<result>::value,
"F must return an optional");
return has_value() ? detail::invoke(std::forward<F>(f), **this)
: result(nullopt);
}
/// \group and_then
/// \synopsis template <class F>\nconstexpr auto and_then(F &&f) &&;
template <class F> TL_OPTIONAL_11_CONSTEXPR auto and_then(F &&f) && {
using result = detail::invoke_result_t<F, T &&>;
static_assert(detail::is_optional<result>::value,
"F must return an optional");
return has_value() ? detail::invoke(std::forward<F>(f), std::move(**this))
: result(nullopt);
}
/// \group and_then
/// \synopsis template <class F>\nconstexpr auto and_then(F &&f) const &;
template <class F> constexpr auto and_then(F &&f) const & {
using result = detail::invoke_result_t<F, const T &>;
static_assert(detail::is_optional<result>::value,
"F must return an optional");
return has_value() ? detail::invoke(std::forward<F>(f), **this)
: result(nullopt);
}
#ifndef TL_OPTIONAL_NO_CONSTRR
/// \group and_then
/// \synopsis template <class F>\nconstexpr auto and_then(F &&f) const &&;
template <class F> constexpr auto and_then(F &&f) const && {
using result = detail::invoke_result_t<F, const T &&>;
static_assert(detail::is_optional<result>::value,
"F must return an optional");
return has_value() ? detail::invoke(std::forward<F>(f), std::move(**this))
: result(nullopt);
}
#endif
#else
/// \group and_then
/// Carries out some operation which returns an optional on the stored
/// object if there is one. \requires `std::invoke(std::forward<F>(f),
/// value())` returns a `std::optional<U>` for some `U`. \returns Let `U` be
/// the result of `std::invoke(std::forward<F>(f), value())`. Returns a
/// `std::optional<U>`. The return value is empty if `*this` is empty,
/// otherwise the return value of `std::invoke(std::forward<F>(f), value())`
/// is returned.
/// \group and_then
/// \synopsis template <class F>\nconstexpr auto and_then(F &&f) &;
template <class F>
TL_OPTIONAL_11_CONSTEXPR detail::invoke_result_t<F, T &> and_then(F &&f) & {
using result = detail::invoke_result_t<F, T &>;
static_assert(detail::is_optional<result>::value,
"F must return an optional");
return has_value() ? detail::invoke(std::forward<F>(f), **this)
: result(nullopt);
}
/// \group and_then
/// \synopsis template <class F>\nconstexpr auto and_then(F &&f) &&;
template <class F>
TL_OPTIONAL_11_CONSTEXPR detail::invoke_result_t<F, T &&> and_then(F &&f) && {
using result = detail::invoke_result_t<F, T &&>;
static_assert(detail::is_optional<result>::value,
"F must return an optional");
return has_value() ? detail::invoke(std::forward<F>(f), std::move(**this))
: result(nullopt);
}
/// \group and_then
/// \synopsis template <class F>\nconstexpr auto and_then(F &&f) const &;
template <class F>
constexpr detail::invoke_result_t<F, const T &> and_then(F &&f) const & {
using result = detail::invoke_result_t<F, const T &>;
static_assert(detail::is_optional<result>::value,
"F must return an optional");
return has_value() ? detail::invoke(std::forward<F>(f), **this)
: result(nullopt);
}
#ifndef TL_OPTIONAL_NO_CONSTRR
/// \group and_then
/// \synopsis template <class F>\nconstexpr auto and_then(F &&f) const &&;
template <class F>
constexpr detail::invoke_result_t<F, const T &&> and_then(F &&f) const && {
using result = detail::invoke_result_t<F, const T &&>;
static_assert(detail::is_optional<result>::value,
"F must return an optional");
return has_value() ? detail::invoke(std::forward<F>(f), std::move(**this))
: result(nullopt);
}
#endif
#endif
#if defined(TL_OPTIONAL_CXX14) && !defined(TL_OPTIONAL_GCC49) && \
!defined(TL_OPTIONAL_GCC54)
/// \brief Carries out some operation on the stored object if there is one.
/// \returns Let `U` be the result of `std::invoke(std::forward<F>(f),
/// value())`. Returns a `std::optional<U>`. The return value is empty if
/// `*this` is empty, otherwise an `optional<U>` is constructed from the
/// return value of `std::invoke(std::forward<F>(f), value())` and is
/// returned.
///
/// \group map
/// \synopsis template <class F> constexpr auto map(F &&f) &;
template <class F> TL_OPTIONAL_11_CONSTEXPR auto map(F &&f) & {
return map_impl(*this, std::forward<F>(f));
}
/// \group map
/// \synopsis template <class F> constexpr auto map(F &&f) &&;
template <class F> TL_OPTIONAL_11_CONSTEXPR auto map(F &&f) && {
return map_impl(std::move(*this), std::forward<F>(f));
}
/// \group map
/// \synopsis template <class F> constexpr auto map(F &&f) const&;
template <class F> constexpr auto map(F &&f) const & {
return map_impl(*this, std::forward<F>(f));
}
/// \group map
/// \synopsis template <class F> constexpr auto map(F &&f) const&&;
template <class F> constexpr auto map(F &&f) const && {
return map_impl(std::move(*this), std::forward<F>(f));
}
#else
/// \brief Carries out some operation on the stored object if there is one.
/// \returns Let `U` be the result of `std::invoke(std::forward<F>(f),
/// value())`. Returns a `std::optional<U>`. The return value is empty if
/// `*this` is empty, otherwise an `optional<U>` is constructed from the
/// return value of `std::invoke(std::forward<F>(f), value())` and is
/// returned.
///
/// \group map
/// \synopsis template <class F> auto map(F &&f) &;
template <class F>
TL_OPTIONAL_11_CONSTEXPR decltype(map_impl(std::declval<optional &>(),
std::declval<F &&>()))
map(F &&f) & {
return map_impl(*this, std::forward<F>(f));
}
/// \group map
/// \synopsis template <class F> auto map(F &&f) &&;
template <class F>
TL_OPTIONAL_11_CONSTEXPR decltype(map_impl(std::declval<optional &&>(),
std::declval<F &&>()))
map(F &&f) && {
return map_impl(std::move(*this), std::forward<F>(f));
}
/// \group map
/// \synopsis template <class F> auto map(F &&f) const&;
template <class F>
constexpr decltype(map_impl(std::declval<const optional &>(),
std::declval<F &&>()))
map(F &&f) const & {
return map_impl(*this, std::forward<F>(f));
}
#ifndef TL_OPTIONAL_NO_CONSTRR
/// \group map
/// \synopsis template <class F> auto map(F &&f) const&&;
template <class F>
constexpr decltype(map_impl(std::declval<const optional &&>(),
std::declval<F &&>()))
map(F &&f) const && {
return map_impl(std::move(*this), std::forward<F>(f));
}
#endif
#endif
/// \brief Calls `f` if the optional is empty
/// \requires `std::invoke_result_t<F>` must be void or convertible to
/// `optional<T>`. \effects If `*this` has a value, returns `*this`.
/// Otherwise, if `f` returns `void`, calls `std::forward<F>(f)` and returns
/// `std::nullopt`. Otherwise, returns `std::forward<F>(f)()`.
///
/// \group or_else
/// \synopsis template <class F> optional<T> or_else (F &&f) &;
template <class F, detail::enable_if_ret_void<F> * = nullptr>
optional<T> TL_OPTIONAL_11_CONSTEXPR or_else(F &&f) & {
if (has_value())
return *this;
std::forward<F>(f)();
return nullopt;
}
/// \exclude
template <class F, detail::disable_if_ret_void<F> * = nullptr>
optional<T> TL_OPTIONAL_11_CONSTEXPR or_else(F &&f) & {
return has_value() ? *this : std::forward<F>(f)();
}
/// \group or_else
/// \synopsis template <class F> optional<T> or_else (F &&f) &&;
template <class F, detail::enable_if_ret_void<F> * = nullptr>
optional<T> or_else(F &&f) && {
if (has_value())
return std::move(*this);
std::forward<F>(f)();
return nullopt;
}
/// \exclude
template <class F, detail::disable_if_ret_void<F> * = nullptr>
optional<T> TL_OPTIONAL_11_CONSTEXPR or_else(F &&f) && {
return has_value() ? std::move(*this) : std::forward<F>(f)();
}
/// \group or_else
/// \synopsis template <class F> optional<T> or_else (F &&f) const &;
template <class F, detail::enable_if_ret_void<F> * = nullptr>
optional<T> or_else(F &&f) const & {
if (has_value())
return *this;
std::forward<F>(f)();
return nullopt;
}
/// \exclude
template <class F, detail::disable_if_ret_void<F> * = nullptr>
optional<T> TL_OPTIONAL_11_CONSTEXPR or_else(F &&f) const & {
return has_value() ? *this : std::forward<F>(f)();
}
#ifndef TL_OPTIONAL_NO_CONSTRR
/// \exclude
template <class F, detail::enable_if_ret_void<F> * = nullptr>
optional<T> or_else(F &&f) const && {
if (has_value())
return std::move(*this);
std::forward<F>(f)();
return nullopt;
}
/// \exclude
template <class F, detail::disable_if_ret_void<F> * = nullptr>
optional<T> or_else(F &&f) const && {
return has_value() ? std::move(*this) : std::forward<F>(f)();
}
#endif
/// \brief Maps the stored value with `f` if there is one, otherwise returns
/// `u`.
///
/// \details If there is a value stored, then `f` is called with `**this`
/// and the value is returned. Otherwise `u` is returned.
///
/// \group map_or
template <class F, class U> U map_or(F &&f, U &&u) & {
return has_value() ? detail::invoke(std::forward<F>(f), **this)
: std::forward<U>(u);
}
/// \group map_or
template <class F, class U> U map_or(F &&f, U &&u) && {
return has_value() ? detail::invoke(std::forward<F>(f), std::move(**this))
: std::forward<U>(u);
}
/// \group map_or
template <class F, class U> U map_or(F &&f, U &&u) const & {
return has_value() ? detail::invoke(std::forward<F>(f), **this)
: std::forward<U>(u);
}
#ifndef TL_OPTIONAL_NO_CONSTRR
/// \group map_or
template <class F, class U> U map_or(F &&f, U &&u) const && {
return has_value() ? detail::invoke(std::forward<F>(f), std::move(**this))
: std::forward<U>(u);
}
#endif
/// \brief Maps the stored value with `f` if there is one, otherwise calls
/// `u` and returns the result.
///
/// \details If there is a value stored, then `f` is
/// called with `**this` and the value is returned. Otherwise
/// `std::forward<U>(u)()` is returned.
///
/// \group map_or_else
/// \synopsis template <class F, class U>\nauto map_or_else(F &&f, U &&u) &;
template <class F, class U>
detail::invoke_result_t<U> map_or_else(F &&f, U &&u) & {
return has_value() ? detail::invoke(std::forward<F>(f), **this)
: std::forward<U>(u)();
}
/// \group map_or_else
/// \synopsis template <class F, class U>\nauto map_or_else(F &&f, U &&u)
/// &&;
template <class F, class U>
detail::invoke_result_t<U> map_or_else(F &&f, U &&u) && {
return has_value() ? detail::invoke(std::forward<F>(f), std::move(**this))
: std::forward<U>(u)();
}
/// \group map_or_else
/// \synopsis template <class F, class U>\nauto map_or_else(F &&f, U &&u)
/// const &;
template <class F, class U>
detail::invoke_result_t<U> map_or_else(F &&f, U &&u) const & {
return has_value() ? detail::invoke(std::forward<F>(f), **this)
: std::forward<U>(u)();
}
#ifndef TL_OPTIONAL_NO_CONSTRR
/// \group map_or_else
/// \synopsis template <class F, class U>\nauto map_or_else(F &&f, U &&u)
/// const &&;
template <class F, class U>
detail::invoke_result_t<U> map_or_else(F &&f, U &&u) const && {
return has_value() ? detail::invoke(std::forward<F>(f), std::move(**this))
: std::forward<U>(u)();
}
#endif
/// \returns `u` if `*this` has a value, otherwise an empty optional.
template <class U>
constexpr optional<typename std::decay<U>::type> conjunction(U &&u) const {
using result = optional<detail::decay_t<U>>;
return has_value() ? result{u} : result{nullopt};
}
/// \returns `rhs` if `*this` is empty, otherwise the current value.
/// \group disjunction
TL_OPTIONAL_11_CONSTEXPR optional disjunction(const optional &rhs) & {
return has_value() ? *this : rhs;
}
/// \group disjunction
constexpr optional disjunction(const optional &rhs) const & {
return has_value() ? *this : rhs;
}
/// \group disjunction
TL_OPTIONAL_11_CONSTEXPR optional disjunction(const optional &rhs) && {
return has_value() ? std::move(*this) : rhs;
}
#ifndef TL_OPTIONAL_NO_CONSTRR
/// \group disjunction
constexpr optional disjunction(const optional &rhs) const && {
return has_value() ? std::move(*this) : rhs;
}
#endif
/// \group disjunction
TL_OPTIONAL_11_CONSTEXPR optional disjunction(optional &&rhs) & {
return has_value() ? *this : std::move(rhs);
}
/// \group disjunction
constexpr optional disjunction(optional &&rhs) const & {
return has_value() ? *this : std::move(rhs);
}
/// \group disjunction
TL_OPTIONAL_11_CONSTEXPR optional disjunction(optional &&rhs) && {
return has_value() ? std::move(*this) : std::move(rhs);
}
#ifndef TL_OPTIONAL_NO_CONSTRR
/// \group disjunction
constexpr optional disjunction(optional &&rhs) const && {
return has_value() ? std::move(*this) : std::move(rhs);
}
#endif
/// Takes the value out of the optional, leaving it empty
/// \group take
optional take() & {
optional ret = *this;
reset();
return ret;
}
/// \group take
optional take() const & {
optional ret = *this;
reset();
return ret;
}
/// \group take
optional take() && {
optional ret = std::move(*this);
reset();
return ret;
}
#ifndef TL_OPTIONAL_NO_CONSTRR
/// \group take
optional take() const && {
optional ret = std::move(*this);
reset();
return ret;
}
#endif
using value_type = T &;
/// Constructs an optional that does not contain a value.
/// \group ctor_empty
constexpr optional() noexcept : m_value(nullptr) {}
/// \group ctor_empty
constexpr optional(nullopt_t) noexcept : m_value(nullptr) {}
/// Copy constructor
///
/// If `rhs` contains a value, the stored value is direct-initialized with
/// it. Otherwise, the constructed optional is empty.
TL_OPTIONAL_11_CONSTEXPR optional(const optional &rhs) noexcept = default;
/// Move constructor
///
/// If `rhs` contains a value, the stored value is direct-initialized with
/// it. Otherwise, the constructed optional is empty.
TL_OPTIONAL_11_CONSTEXPR optional(optional &&rhs) = default;
/// Constructs the stored value with `u`.
/// \synopsis template <class U=T> constexpr optional(U &&u);
template <
class U = T,
detail::enable_if_t<std::is_convertible<U &&, T &>::value> * = nullptr,
detail::enable_if_t<!detail::is_optional<detail::decay_t<U>>> * = nullptr>
constexpr optional(U &&u) : m_value(std::addressof(u)) {}
/// \exclude
template <class U = T, detail::enable_if_t<
!std::is_convertible<U &, T &>::value> * = nullptr>
constexpr optional(U &&u) : base(in_place, std::forward<U>(u)) {}
/// \exclude
template <class U, detail::enable_if_t<
!std::is_convertible<const U &, T>::value> * = nullptr>
constexpr explicit optional(const optional<U> &rhs) : optional(*rhs) {}
/// No-op
~optional() = default;
/// Assignment to empty.
///
/// Destroys the current value if there is one.
optional &operator=(nullopt_t) noexcept {
m_value = nullptr;
return *this;
}
/// Copy assignment.
///
/// Copies the value from `rhs` if there is one. Otherwise resets the stored
/// value in `*this`.
optional &operator=(const optional &rhs) = default;
/// Assigns the stored value from `u`, destroying the old value if there was
/// one.
/// \synopsis optional &operator=(U &&u);
template <class U = T,
detail::enable_if<!detail::is_optional<detail::decay_t<U>>::value>
* = nullptr>
optional &operator=(U &&u) {
m_value = std::addressof(u);
return *this;
}
/// Converting copy assignment operator.
///
/// Copies the value from `rhs` if there is one. Otherwise resets the stored
/// value in `*this`.
/// \synopsis optional &operator=(const optional<U> & rhs);
template <class U,
detail::enable_if<std::is_convertible<U &, T &>::value> * = nullptr>
optional &operator=(const optional<U> &rhs) {
m_value = std::addressof(rhs.value());
return *this;
}
/// Constructs the value in-place, destroying the current one if there is
/// one. \group emplace
template <class... Args> T &emplace(Args &&... args) noexcept {
static_assert(std::is_constructible<T, Args &&...>::value,
"T must be constructible with Args");
*this = nullopt;
this->construct(std::forward<Args>(args)...);
}
/// Swaps this optional with the other.
///
/// If neither optionals have a value, nothing happens.
/// If both have a value, the values are swapped.
/// If one has a value, it is moved to the other and the movee is left
/// valueless.
void
swap(optional &rhs) noexcept {
std::swap(m_value, rhs.m_value);
}
/// \returns a pointer to the stored value
/// \requires a value is stored
/// \group pointer
/// \synopsis constexpr const T *operator->() const;
constexpr const T *operator->() const {
return m_value;
}
/// \group pointer
/// \synopsis constexpr T *operator->();
TL_OPTIONAL_11_CONSTEXPR T *operator->() {
return m_value;
}
/// \returns the stored value
/// \requires a value is stored
/// \group deref
/// \synopsis constexpr T &operator*();
TL_OPTIONAL_11_CONSTEXPR T &operator*() & { return *m_value; }
/// \group deref
/// \synopsis constexpr const T &operator*() const;
constexpr const T &operator*() const & { return *m_value; }
/// \exclude
TL_OPTIONAL_11_CONSTEXPR T &&operator*() && {
return std::move(*m_value);
}
#ifndef TL_OPTIONAL_NO_CONSTRR
/// \exclude
constexpr const T &&operator*() const && { return std::move(*m_value); }
#endif
/// \returns whether or not the optional has a value
/// \group has_value
constexpr bool has_value() const noexcept { return m_value != nullptr; }
/// \group has_value
constexpr explicit operator bool() const noexcept {
return m_value != nullptr;
}
/// \returns the contained value if there is one, otherwise throws
/// [bad_optional_access]
/// \group value
/// synopsis constexpr T &value();
TL_OPTIONAL_11_CONSTEXPR T &value() & {
if (has_value())
return *m_value;
throw bad_optional_access();
}
/// \group value
/// \synopsis constexpr const T &value() const;
TL_OPTIONAL_11_CONSTEXPR const T &value() const & {
if (has_value())
return *m_value;
throw bad_optional_access();
}
/// \exclude
TL_OPTIONAL_11_CONSTEXPR T &&value() && {
if (has_value())
return std::move(*m_value);
throw bad_optional_access();
}
#ifndef TL_OPTIONAL_NO_CONSTRR
/// \exclude
constexpr const T &&value() const && {
if (has_value())
return std::move(*m_value);
throw bad_optional_access();
}
#endif
/// \returns the stored value if there is one, otherwise returns `u`
/// \group value_or
template <class U> constexpr T value_or(U &&u) const & {
static_assert(std::is_copy_constructible<T>::value &&
std::is_convertible<U &&, T>::value,
"T must be copy constructible and convertible from U");
return has_value() ? **this : static_cast<T>(std::forward<U>(u));
}
/// \group value_or
template <class U> constexpr T value_or(U &&u) && {
static_assert(std::is_move_constructible<T>::value &&
std::is_convertible<U &&, T>::value,
"T must be move constructible and convertible from U");
return has_value() ? **this : static_cast<T>(std::forward<U>(u));
}
/// Destroys the stored value if one exists, making the optional empty
void reset() noexcept {
m_value = nullptr;
}
}; // namespace tl
/// \group relop
/// \brief Compares two optional objects
/// \details If both optionals contain a value, they are compared with `T`s
/// relational operators. Otherwise `lhs` and `rhs` are equal only if they are
/// both empty, and `lhs` is less than `rhs` only if `rhs` is empty and `lhs`
/// is not.
template <class T, class U>
inline constexpr bool operator==(const optional<T> &lhs,
const optional<U> &rhs) {
return lhs.has_value() == rhs.has_value() &&
(!lhs.has_value() || *lhs == *rhs);
}
/// \group relop
template <class T, class U>
inline constexpr bool operator!=(const optional<T> &lhs,
const optional<U> &rhs) {
return lhs.has_value() != rhs.has_value() ||
(lhs.has_value() && *lhs != *rhs);
}
/// \group relop
template <class T, class U>
inline constexpr bool operator<(const optional<T> &lhs,
const optional<U> &rhs) {
return rhs.has_value() && (!lhs.has_value() || *lhs < *rhs);
}
/// \group relop
template <class T, class U>
inline constexpr bool operator>(const optional<T> &lhs,
const optional<U> &rhs) {
return lhs.has_value() && (!rhs.has_value() || *lhs > *rhs);
}
/// \group relop
template <class T, class U>
inline constexpr bool operator<=(const optional<T> &lhs,
const optional<U> &rhs) {
return !lhs.has_value() || (rhs.has_value() && *lhs <= *rhs);
}
/// \group relop
template <class T, class U>
inline constexpr bool operator>=(const optional<T> &lhs,
const optional<U> &rhs) {
return !rhs.has_value() || (lhs.has_value() && *lhs >= *rhs);
}
/// \group relop_nullopt
/// \brief Compares an optional to a `nullopt`
/// \details Equivalent to comparing the optional to an empty optional
template <class T>
inline constexpr bool operator==(const optional<T> &lhs, nullopt_t) noexcept {
return !lhs.has_value();
}
/// \group relop_nullopt
template <class T>
inline constexpr bool operator==(nullopt_t, const optional<T> &rhs) noexcept {
return !rhs.has_value();
}
/// \group relop_nullopt
template <class T>
inline constexpr bool operator!=(const optional<T> &lhs, nullopt_t) noexcept {
return lhs.has_value();
}
/// \group relop_nullopt
template <class T>
inline constexpr bool operator!=(nullopt_t, const optional<T> &rhs) noexcept {
return rhs.has_value();
}
/// \group relop_nullopt
template <class T>
inline constexpr bool operator<(const optional<T> &, nullopt_t) noexcept {
return false;
}
/// \group relop_nullopt
template <class T>
inline constexpr bool operator<(nullopt_t, const optional<T> &rhs) noexcept {
return rhs.has_value();
}
/// \group relop_nullopt
template <class T>
inline constexpr bool operator<=(const optional<T> &lhs, nullopt_t) noexcept {
return !lhs.has_value();
}
/// \group relop_nullopt
template <class T>
inline constexpr bool operator<=(nullopt_t, const optional<T> &) noexcept {
return true;
}
/// \group relop_nullopt
template <class T>
inline constexpr bool operator>(const optional<T> &lhs, nullopt_t) noexcept {
return lhs.has_value();
}
/// \group relop_nullopt
template <class T>
inline constexpr bool operator>(nullopt_t, const optional<T> &) noexcept {
return false;
}
/// \group relop_nullopt
template <class T>
inline constexpr bool operator>=(const optional<T> &, nullopt_t) noexcept {
return true;
}
/// \group relop_nullopt
template <class T>
inline constexpr bool operator>=(nullopt_t, const optional<T> &rhs) noexcept {
return !rhs.has_value();
}
/// \group relop_t
/// \brief Compares the optional with a value.
/// \details If the optional has a value, it is compared with the other value
/// using `T`s relational operators. Otherwise, the optional is considered
/// less than the value.
template <class T, class U>
inline constexpr bool operator==(const optional<T> &lhs, const U &rhs) {
return lhs.has_value() ? *lhs == rhs : false;
}
/// \group relop_t
template <class T, class U>
inline constexpr bool operator==(const U &lhs, const optional<T> &rhs) {
return rhs.has_value() ? lhs == *rhs : false;
}
/// \group relop_t
template <class T, class U>
inline constexpr bool operator!=(const optional<T> &lhs, const U &rhs) {
return lhs.has_value() ? *lhs != rhs : true;
}
/// \group relop_t
template <class T, class U>
inline constexpr bool operator!=(const U &lhs, const optional<T> &rhs) {
return rhs.has_value() ? lhs != *rhs : true;
}
/// \group relop_t
template <class T, class U>
inline constexpr bool operator<(const optional<T> &lhs, const U &rhs) {
return lhs.has_value() ? *lhs < rhs : true;
}
/// \group relop_t
template <class T, class U>
inline constexpr bool operator<(const U &lhs, const optional<T> &rhs) {
return rhs.has_value() ? lhs < *rhs : false;
}
/// \group relop_t
template <class T, class U>
inline constexpr bool operator<=(const optional<T> &lhs, const U &rhs) {
return lhs.has_value() ? *lhs <= rhs : true;
}
/// \group relop_t
template <class T, class U>
inline constexpr bool operator<=(const U &lhs, const optional<T> &rhs) {
return rhs.has_value() ? lhs <= *rhs : false;
}
/// \group relop_t
template <class T, class U>
inline constexpr bool operator>(const optional<T> &lhs, const U &rhs) {
return lhs.has_value() ? *lhs > rhs : false;
}
/// \group relop_t
template <class T, class U>
inline constexpr bool operator>(const U &lhs, const optional<T> &rhs) {
return rhs.has_value() ? lhs > *rhs : true;
}
/// \group relop_t
template <class T, class U>
inline constexpr bool operator>=(const optional<T> &lhs, const U &rhs) {
return lhs.has_value() ? *lhs >= rhs : false;
}
/// \group relop_t
template <class T, class U>
inline constexpr bool operator>=(const U &lhs, const optional<T> &rhs) {
return rhs.has_value() ? lhs >= *rhs : true;
}
/// \synopsis template <class T>\nvoid swap(optional<T> &lhs, optional<T>
/// &rhs);
template <class T,
detail::enable_if_t<std::is_move_constructible<T>::value> * = nullptr,
detail::enable_if_t<detail::is_swappable<T>::value> * = nullptr>
void swap(optional<T> &lhs,
optional<T> &rhs) noexcept(noexcept(lhs.swap(rhs))) {
return lhs.swap(rhs);
}
template <class T>
inline constexpr optional<detail::decay_t<T>> make_optional(T &&v) {
return optional<detail::decay_t<T>>(std::forward<T>(v));
}
template <class T, class... Args>
inline constexpr optional<T> make_optional(Args &&... args) {
return optional<T>(in_place, std::forward<Args>(args)...);
}
template <class T, class U, class... Args>
inline constexpr optional<T> make_optional(std::initializer_list<U> il,
Args &&... args) {
return optional<T>(in_place, il, std::forward<Args>(args)...);
}
/// \exclude
namespace detail {
#ifdef TL_OPTIONAL_CX14