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Simon Brand
2017-10-27 09:07:56 +01:00
parent f97fdcd904
commit 9ee90e0bff
1 changed files with 548 additions and 493 deletions
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expected.hpp
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@@ -14,108 +14,109 @@
#ifndef TL_EXPECTED_HPP #ifndef TL_EXPECTED_HPP
#define TL_EXPECTED_HPP #define TL_EXPECTED_HPP
#include <exception>
#include <type_traits> #include <type_traits>
#include <utility> #include <utility>
#include <exception>
namespace tl { namespace tl {
namespace detail { namespace detail {
template <bool E, class T = void> template <bool E, class T = void>
using enable_if_t = typename std::enable_if<E, T>::type; using enable_if_t = typename std::enable_if<E, T>::type;
} }
#ifndef TL_IN_PLACE_T_DEFINED #ifndef TL_IN_PLACE_T_DEFINED
#define TL_IN_PLACE_T_DEFINED #define TL_IN_PLACE_T_DEFINED
/// \brief A tag type to tell optional to construct its value in-place /// \brief A tag type to tell optional to construct its value in-place
struct in_place_t { struct in_place_t {
explicit in_place_t() = default; explicit in_place_t() = default;
}; };
/// \brief A tag to tell optional to construct its value in-place /// \brief A tag to tell optional to construct its value in-place
static constexpr in_place_t in_place{}; static constexpr in_place_t in_place{};
#endif #endif
template <class E> template <class E> class unexpected {
class unexpected { public:
public:
static_assert(!std::is_same<E, void>::value, "E must not be void"); static_assert(!std::is_same<E, void>::value, "E must not be void");
unexpected() = delete; unexpected() = delete;
constexpr explicit unexpected(const E& e) constexpr explicit unexpected(const E &e) : m_val(e) {}
: m_val(e) {}
constexpr explicit unexpected(E&& e) constexpr explicit unexpected(E &&e) : m_val(std::move(e)) {}
: m_val(std::move(e)) {}
constexpr const E& value() const & { return m_val; } constexpr const E &value() const & { return m_val; }
constexpr E& value() & { return m_val; } constexpr E &value() & { return m_val; }
constexpr E&& value() && { return std::move(m_val); } constexpr E &&value() && { return std::move(m_val); }
constexpr E const&& value() const&& { return std::move(m_val); } constexpr E const &&value() const && { return std::move(m_val); }
private:
E m_val; // exposition only
};
template <class E> private:
constexpr bool E m_val;
operator==(const unexpected<E>& lhs, const unexpected<E>& rhs) { };
template <class E>
constexpr bool operator==(const unexpected<E> &lhs, const unexpected<E> &rhs) {
return lhs.value() == rhs.value(); return lhs.value() == rhs.value();
} }
template <class E> template <class E>
constexpr bool constexpr bool operator!=(const unexpected<E> &lhs, const unexpected<E> &rhs) {
operator!=(const unexpected<E>& lhs, const unexpected<E>& rhs) {
return lhs.value() != rhs.value(); return lhs.value() != rhs.value();
} }
template <class E> template <class E>
constexpr bool constexpr bool operator<(const unexpected<E> &lhs, const unexpected<E> &rhs) {
operator<(const unexpected<E>& lhs, const unexpected<E>& rhs) {
return lhs.value() < rhs.value(); return lhs.value() < rhs.value();
} }
template <class E> template <class E>
constexpr bool constexpr bool operator<=(const unexpected<E> &lhs, const unexpected<E> &rhs) {
operator<=(const unexpected<E>& lhs, const unexpected<E>& rhs) {
return lhs.value() <= rhs.value(); return lhs.value() <= rhs.value();
} }
template <class E> template <class E>
constexpr bool constexpr bool operator>(const unexpected<E> &lhs, const unexpected<E> &rhs) {
operator>(const unexpected<E>& lhs, const unexpected<E>& rhs) {
return lhs.value() > rhs.value(); return lhs.value() > rhs.value();
} }
template <class E> template <class E>
constexpr bool constexpr bool operator>=(const unexpected<E> &lhs, const unexpected<E> &rhs) {
operator>=(const unexpected<E>& lhs, const unexpected<E>& rhs) {
return lhs.value() >= rhs.value(); return lhs.value() >= rhs.value();
} }
struct unexpect_t { struct unexpect_t {
unexpect_t() = default; unexpect_t() = default;
}; };
static constexpr unexpect_t unexpect{}; static constexpr unexpect_t unexpect{};
namespace detail { namespace detail {
template <class T, class E, bool = std::is_trivially_destructible<T>::value, bool = std::is_trivially_destructible<E>::value> template <class T, class E, bool = std::is_trivially_destructible<T>::value,
struct expected_storage_base { bool = std::is_trivially_destructible<E>::value>
constexpr expected_storage_base() struct expected_storage_base {
: m_val(T{}), m_has_val(true) {} constexpr expected_storage_base() : m_val(T{}), m_has_val(true) {}
template <class... Args, detail::enable_if_t<std::is_constructible<T, Args&&...>::value>* = nullptr> template <class... Args,
constexpr expected_storage_base(in_place_t, Args&&... args) : detail::enable_if_t<std::is_constructible<T, Args &&...>::value> * =
m_val(std::forward<Args>(args)...), m_has_val(true) {} nullptr>
constexpr expected_storage_base(in_place_t, Args &&... args)
: m_val(std::forward<Args>(args)...), m_has_val(true) {}
template <class U, class... Args, detail::enable_if_t<std::is_constructible<T, std::initializer_list<U>&, Args&&...>::value>* = nullptr> template <class U, class... Args,
constexpr expected_storage_base (in_place_t, std::initializer_list<U> il, Args&&... args) : detail::enable_if_t<std::is_constructible<
m_val(il, std::forward<Args>(args)...), m_has_val(true) {} T, std::initializer_list<U> &, Args &&...>::value> * = nullptr>
template <class... Args, detail::enable_if_t<std::is_constructible<E, Args&&...>::value>* = nullptr> constexpr expected_storage_base(in_place_t, std::initializer_list<U> il,
constexpr explicit expected_storage_base(unexpect_t, Args&&... args) : Args &&... args)
m_unexpect(std::forward<Args>(args)...), m_has_val(false) {} : m_val(il, std::forward<Args>(args)...), m_has_val(true) {}
template <class... Args,
template <class U, class... Args, detail::enable_if_t<std::is_constructible<E, std::initializer_list<U>&, Args&&...>::value>* = nullptr> detail::enable_if_t<std::is_constructible<E, Args &&...>::value> * =
constexpr explicit expected_storage_base(unexpect_t, std::initializer_list<U> il, Args&&... args) : nullptr>
m_unexpect(il, std::forward<Args>(args)...), m_has_val(false) {} constexpr explicit expected_storage_base(unexpect_t, Args &&... args)
: m_unexpect(std::forward<Args>(args)...), m_has_val(false) {}
template <class U, class... Args,
detail::enable_if_t<std::is_constructible<
E, std::initializer_list<U> &, Args &&...>::value> * = nullptr>
constexpr explicit expected_storage_base(unexpect_t,
std::initializer_list<U> il,
Args &&... args)
: m_unexpect(il, std::forward<Args>(args)...), m_has_val(false) {}
~expected_storage_base() { ~expected_storage_base() {
if (m_has_val) { if (m_has_val) {
m_val.~T(); m_val.~T();
} } else {
else {
m_unexpect.~unexpected<E>(); m_unexpect.~unexpected<E>();
} }
} }
@@ -124,29 +125,36 @@ namespace detail {
T m_val; T m_val;
unexpected<E> m_unexpect; unexpected<E> m_unexpect;
}; };
}; };
template <class T, class E> template <class T, class E> struct expected_storage_base<T, E, true, true> {
struct expected_storage_base<T,E,true,true> { constexpr expected_storage_base() : m_val(T{}), m_has_val(true) {}
constexpr expected_storage_base()
: m_val(T{}), m_has_val(true) {}
template <class... Args,
detail::enable_if_t<std::is_constructible<T, Args &&...>::value> * =
nullptr>
constexpr expected_storage_base(in_place_t, Args &&... args)
: m_val(std::forward<Args>(args)...), m_has_val(true) {}
template <class... Args, detail::enable_if_t<std::is_constructible<T, Args&&...>::value>* = nullptr> template <class U, class... Args,
constexpr expected_storage_base(in_place_t, Args&&... args) : detail::enable_if_t<std::is_constructible<
m_val(std::forward<Args>(args)...), m_has_val(true) {} T, std::initializer_list<U> &, Args &&...>::value> * = nullptr>
constexpr expected_storage_base(in_place_t, std::initializer_list<U> il,
template <class U, class... Args, detail::enable_if_t<std::is_constructible<T, std::initializer_list<U>&, Args&&...>::value>* = nullptr> Args &&... args)
constexpr expected_storage_base (in_place_t, std::initializer_list<U> il, Args&&... args) : : m_val(il, std::forward<Args>(args)...), m_has_val(true) {}
m_val(il, std::forward<Args>(args)...), m_has_val(true) {} template <class... Args,
template <class... Args, detail::enable_if_t<std::is_constructible<E, Args&&...>::value>* = nullptr> detail::enable_if_t<std::is_constructible<E, Args &&...>::value> * =
constexpr explicit expected_storage_base(unexpect_t, Args&&... args) : nullptr>
m_unexpect(std::forward<Args>(args)...), m_has_val(false) {} constexpr explicit expected_storage_base(unexpect_t, Args &&... args)
: m_unexpect(std::forward<Args>(args)...), m_has_val(false) {}
template <class U, class... Args, detail::enable_if_t<std::is_constructible<E, std::initializer_list<U>&, Args&&...>::value>* = nullptr>
constexpr explicit expected_storage_base(unexpect_t, std::initializer_list<U> il, Args&&... args) :
m_unexpect(il, std::forward<Args>(args)...), m_has_val(false) {}
template <class U, class... Args,
detail::enable_if_t<std::is_constructible<
E, std::initializer_list<U> &, Args &&...>::value> * = nullptr>
constexpr explicit expected_storage_base(unexpect_t,
std::initializer_list<U> il,
Args &&... args)
: m_unexpect(il, std::forward<Args>(args)...), m_has_val(false) {}
~expected_storage_base() = default; ~expected_storage_base() = default;
bool m_has_val; bool m_has_val;
@@ -154,29 +162,36 @@ namespace detail {
T m_val; T m_val;
unexpected<E> m_unexpect; unexpected<E> m_unexpect;
}; };
}; };
template <class T, class E> template <class T, class E> struct expected_storage_base<T, E, true, false> {
struct expected_storage_base<T,E,true,false> { constexpr expected_storage_base() : m_val(T{}), m_has_val(true) {}
constexpr expected_storage_base()
: m_val(T{}), m_has_val(true) {}
template <class... Args,
detail::enable_if_t<std::is_constructible<T, Args &&...>::value> * =
nullptr>
constexpr expected_storage_base(in_place_t, Args &&... args)
: m_val(std::forward<Args>(args)...), m_has_val(true) {}
template <class... Args, detail::enable_if_t<std::is_constructible<T, Args&&...>::value>* = nullptr> template <class U, class... Args,
constexpr expected_storage_base(in_place_t, Args&&... args) : detail::enable_if_t<std::is_constructible<
m_val(std::forward<Args>(args)...), m_has_val(true) {} T, std::initializer_list<U> &, Args &&...>::value> * = nullptr>
constexpr expected_storage_base(in_place_t, std::initializer_list<U> il,
template <class U, class... Args, detail::enable_if_t<std::is_constructible<T, std::initializer_list<U>&, Args&&...>::value>* = nullptr> Args &&... args)
constexpr expected_storage_base (in_place_t, std::initializer_list<U> il, Args&&... args) : : m_val(il, std::forward<Args>(args)...), m_has_val(true) {}
m_val(il, std::forward<Args>(args)...), m_has_val(true) {} template <class... Args,
template <class... Args, detail::enable_if_t<std::is_constructible<E, Args&&...>::value>* = nullptr> detail::enable_if_t<std::is_constructible<E, Args &&...>::value> * =
constexpr explicit expected_storage_base(unexpect_t, Args&&... args) : nullptr>
m_unexpect(std::forward<Args>(args)...), m_has_val(false) {} constexpr explicit expected_storage_base(unexpect_t, Args &&... args)
: m_unexpect(std::forward<Args>(args)...), m_has_val(false) {}
template <class U, class... Args, detail::enable_if_t<std::is_constructible<E, std::initializer_list<U>&, Args&&...>::value>* = nullptr>
constexpr explicit expected_storage_base(unexpect_t, std::initializer_list<U> il, Args&&... args) :
m_unexpect(il, std::forward<Args>(args)...), m_has_val(false) {}
template <class U, class... Args,
detail::enable_if_t<std::is_constructible<
E, std::initializer_list<U> &, Args &&...>::value> * = nullptr>
constexpr explicit expected_storage_base(unexpect_t,
std::initializer_list<U> il,
Args &&... args)
: m_unexpect(il, std::forward<Args>(args)...), m_has_val(false) {}
~expected_storage_base() { ~expected_storage_base() {
if (!m_has_val) { if (!m_has_val) {
@@ -189,30 +204,36 @@ namespace detail {
T m_val; T m_val;
unexpected<E> m_unexpect; unexpected<E> m_unexpect;
}; };
};
}; template <class T, class E> struct expected_storage_base<T, E, false, true> {
constexpr expected_storage_base() : m_val(T{}), m_has_val(true) {}
template <class T, class E> template <class... Args,
struct expected_storage_base<T,E,false,true> { detail::enable_if_t<std::is_constructible<T, Args &&...>::value> * =
constexpr expected_storage_base() nullptr>
: m_val(T{}), m_has_val(true) {} constexpr expected_storage_base(in_place_t, Args &&... args)
: m_val(std::forward<Args>(args)...), m_has_val(true) {}
template <class U, class... Args,
detail::enable_if_t<std::is_constructible<
T, std::initializer_list<U> &, Args &&...>::value> * = nullptr>
constexpr expected_storage_base(in_place_t, std::initializer_list<U> il,
Args &&... args)
: m_val(il, std::forward<Args>(args)...), m_has_val(true) {}
template <class... Args,
detail::enable_if_t<std::is_constructible<E, Args &&...>::value> * =
nullptr>
constexpr explicit expected_storage_base(unexpect_t, Args &&... args)
: m_unexpect(std::forward<Args>(args)...), m_has_val(false) {}
template <class... Args, detail::enable_if_t<std::is_constructible<T, Args&&...>::value>* = nullptr> template <class U, class... Args,
constexpr expected_storage_base(in_place_t, Args&&... args) : detail::enable_if_t<std::is_constructible<
m_val(std::forward<Args>(args)...), m_has_val(true) {} E, std::initializer_list<U> &, Args &&...>::value> * = nullptr>
constexpr explicit expected_storage_base(unexpect_t,
template <class U, class... Args, detail::enable_if_t<std::is_constructible<T, std::initializer_list<U>&, Args&&...>::value>* = nullptr> std::initializer_list<U> il,
constexpr expected_storage_base(in_place_t, std::initializer_list<U> il, Args&&... args) : Args &&... args)
m_val(il, std::forward<Args>(args)...), m_has_val(true) {} : m_unexpect(il, std::forward<Args>(args)...), m_has_val(false) {}
template <class... Args, detail::enable_if_t<std::is_constructible<E, Args&&...>::value>* = nullptr>
constexpr explicit expected_storage_base(unexpect_t, Args&&... args) :
m_unexpect(std::forward<Args>(args)...), m_has_val(false) {}
template <class U, class... Args, detail::enable_if_t<std::is_constructible<E, std::initializer_list<U>&, Args&&...>::value>* = nullptr>
constexpr explicit expected_storage_base(unexpect_t, std::initializer_list<U> il, Args&&... args) :
m_unexpect(il, std::forward<Args>(args)...), m_has_val(false) {}
~expected_storage_base() { ~expected_storage_base() {
if (m_has_val) { if (m_has_val) {
@@ -224,46 +245,51 @@ namespace detail {
T m_val; T m_val;
unexpected<E> m_unexpect; unexpected<E> m_unexpect;
}; };
}; };
template <class E> template <class E> struct expected_storage_base<void, E, false, true> {
struct expected_storage_base<void,E,false,true> { constexpr expected_storage_base() : m_val(), m_has_val(true) {}
constexpr expected_storage_base()
: m_val(), m_has_val(true) {}
template <class... Args,
detail::enable_if_t<std::is_constructible<E, Args &&...>::value> * =
nullptr>
constexpr explicit expected_storage_base(unexpect_t, Args &&... args)
: m_unexpect(std::forward<Args>(args)...), m_has_val(false) {}
template <class... Args, detail::enable_if_t<std::is_constructible<E, Args&&...>::value>* = nullptr> template <class U, class... Args,
constexpr explicit expected_storage_base(unexpect_t, Args&&... args) : detail::enable_if_t<std::is_constructible<
m_unexpect(std::forward<Args>(args)...), m_has_val(false) {} E, std::initializer_list<U> &, Args &&...>::value> * = nullptr>
constexpr explicit expected_storage_base(unexpect_t,
template <class U, class... Args, detail::enable_if_t<std::is_constructible<E, std::initializer_list<U>&, Args&&...>::value>* = nullptr> std::initializer_list<U> il,
constexpr explicit expected_storage_base(unexpect_t, std::initializer_list<U> il, Args&&... args) : Args &&... args)
m_unexpect(il, std::forward<Args>(args)...), m_has_val(false) {} : m_unexpect(il, std::forward<Args>(args)...), m_has_val(false) {}
~expected_storage_base() = default; ~expected_storage_base() = default;
bool m_has_val; bool m_has_val;
struct dummy{}; struct dummy {};
union { union {
dummy m_val; dummy m_val;
unexpected<E> m_unexpect; unexpected<E> m_unexpect;
}; };
}; };
template <class E> template <class E> struct expected_storage_base<void, E, false, false> {
struct expected_storage_base<void,E,false,false> { constexpr expected_storage_base() : m_val(), m_has_val(true) {}
constexpr expected_storage_base()
: m_val(), m_has_val(true) {}
template <class... Args, detail::enable_if_t<std::is_constructible<E, Args&&...>::value>* = nullptr> template <class... Args,
constexpr explicit expected_storage_base(unexpect_t, Args&&... args) : detail::enable_if_t<std::is_constructible<E, Args &&...>::value> * =
m_unexpect(std::forward<Args>(args)...), m_has_val(false) {} nullptr>
constexpr explicit expected_storage_base(unexpect_t, Args &&... args)
template <class U, class... Args, detail::enable_if_t<std::is_constructible<E, std::initializer_list<U>&, Args&&...>::value>* = nullptr> : m_unexpect(std::forward<Args>(args)...), m_has_val(false) {}
constexpr explicit expected_storage_base(unexpect_t, std::initializer_list<U> il, Args&&... args) :
m_unexpect(il, std::forward<Args>(args)...), m_has_val(false) {}
template <class U, class... Args,
detail::enable_if_t<std::is_constructible<
E, std::initializer_list<U> &, Args &&...>::value> * = nullptr>
constexpr explicit expected_storage_base(unexpect_t,
std::initializer_list<U> il,
Args &&... args)
: m_unexpect(il, std::forward<Args>(args)...), m_has_val(false) {}
~expected_storage_base() { ~expected_storage_base() {
if (m_has_val) { if (m_has_val) {
@@ -272,54 +298,55 @@ namespace detail {
} }
bool m_has_val; bool m_has_val;
struct dummy{}; struct dummy {};
union { union {
dummy m_val; dummy m_val;
unexpected<E> m_unexpect; unexpected<E> m_unexpect;
}; };
}; };
//TODO, conditionally delete things // TODO, conditionally delete things
template <class T, class E> template <class T, class E> class expected_ctor_base {};
class expected_ctor_base{}; } // namespace detail
}
template <class E> class bad_expected_access : public std::exception {
template <class E>
class bad_expected_access : public std::exception {
public: public:
explicit bad_expected_access(E e) explicit bad_expected_access(E e) : m_val(std::move(e)) {}
: m_val(std::move(e)) {}
virtual const char* what() const noexcept override { virtual const char *what() const noexcept override {
return "Bad expected access"; return "Bad expected access";
} }
const E& error() const& { return m_val; } const E &error() const & { return m_val; }
E& error() & { return m_val; } E &error() & { return m_val; }
const E&& error() const && { return std::move(m_val); } const E &&error() const && { return std::move(m_val); }
E&& error() && { return std::move(m_val); } E &&error() && { return std::move(m_val); }
private: private:
E m_val; E m_val;
}; };
template <class T, class E> template <class T, class E>
class expected : private detail::expected_storage_base<T,E>, private detail::expected_ctor_base<T,E> { class expected : private detail::expected_storage_base<T, E>,
private detail::expected_ctor_base<T, E> {
static_assert(!std::is_reference<T>::value, "T must not be a reference"); static_assert(!std::is_reference<T>::value, "T must not be a reference");
static_assert(!std::is_same<T, std::remove_cv<in_place_t>>::value, "T must not be in_place_t"); static_assert(!std::is_same<T, std::remove_cv<in_place_t>>::value,
static_assert(!std::is_same<T, std::remove_cv<unexpect_t>>::value, "T must not be unexpect_t"); "T must not be in_place_t");
static_assert(!std::is_same<T, std::remove_cv<unexpected<E>>>::value, "T must not be unexpected<E>"); static_assert(!std::is_same<T, std::remove_cv<unexpect_t>>::value,
"T must not be unexpect_t");
static_assert(!std::is_same<T, std::remove_cv<unexpected<E>>>::value,
"T must not be unexpected<E>");
static_assert(!std::is_reference<E>::value, "E must not be a reference"); static_assert(!std::is_reference<E>::value, "E must not be a reference");
static_assert(!std::is_same<T, void>::value, "T must not be void"); static_assert(!std::is_same<T, void>::value, "T must not be void");
T* valptr() { return std::addressof(this->m_val); } T *valptr() { return std::addressof(this->m_val); }
unexpected<E>* errptr() { return std::addressof(this->m_unexpect); } unexpected<E> *errptr() { return std::addressof(this->m_unexpect); }
T& val() { return this->m_val; } T &val() { return this->m_val; }
unexpected<E>& err() { return this->m_unexpect; } unexpected<E> &err() { return this->m_unexpect; }
const T& val() const { return this->m_val; } const T &val() const { return this->m_val; }
const unexpected<E>& err() const { return this->m_unexpect; } const unexpected<E> &err() const { return this->m_unexpect; }
using storage_base = detail::expected_storage_base<T,E>; using storage_base = detail::expected_storage_base<T, E>;
public: public:
typedef T value_type; typedef T value_type;
@@ -328,243 +355,271 @@ public:
constexpr expected() = default; constexpr expected() = default;
template <class... Args, detail::enable_if_t<std::is_constructible<T, Args&&...>::value>* = nullptr> template <class... Args,
constexpr expected(in_place_t, Args&&... args) : detail::enable_if_t<std::is_constructible<T, Args &&...>::value> * =
storage_base(in_place, std::forward<Args>(args)...){} nullptr>
constexpr expected(in_place_t, Args &&... args)
: storage_base(in_place, std::forward<Args>(args)...) {}
template <class U, class... Args, detail::enable_if_t<std::is_constructible<T, std::initializer_list<U>&, Args&&...>::value>* = nullptr> template <class U, class... Args,
constexpr expected(in_place_t, std::initializer_list<U> il, Args&&... args) : detail::enable_if_t<std::is_constructible<
storage_base(in_place, il, std::forward<Args>(args)...){} T, std::initializer_list<U> &, Args &&...>::value> * = nullptr>
constexpr expected(in_place_t, std::initializer_list<U> il, Args &&... args)
: storage_base(in_place, il, std::forward<Args>(args)...) {}
template <class G = E, detail::enable_if_t<std::is_constructible<E, const G&>::value>* = nullptr, detail::enable_if_t<!std::is_convertible<const G&, E>::value>* = nullptr> template <class G = E,
explicit constexpr expected(unexpected<G> const& e) detail::enable_if_t<std::is_constructible<E, const G &>::value> * =
nullptr,
detail::enable_if_t<!std::is_convertible<const G &, E>::value> * =
nullptr>
explicit constexpr expected(unexpected<G> const &e)
: storage_base(unexpect, e) {} : storage_base(unexpect, e) {}
template <class G = E, detail::enable_if_t<std::is_constructible<E, const G&>::value>* = nullptr, detail::enable_if_t<std::is_convertible<const G&, E>::value>* = nullptr> template <
constexpr expected(unexpected<G> const& e) class G = E,
: storage_base(unexpect, e) {} detail::enable_if_t<std::is_constructible<E, const G &>::value> * =
nullptr,
detail::enable_if_t<std::is_convertible<const G &, E>::value> * = nullptr>
constexpr expected(unexpected<G> const &e) : storage_base(unexpect, e) {}
template <class G = E, detail::enable_if_t<std::is_constructible<E, G&&>::value>* = nullptr, detail::enable_if_t<!std::is_convertible<G&&, E>::value>* = nullptr> template <
explicit constexpr expected(unexpected<G> && e) noexcept(std::is_nothrow_constructible<E, G&&>::value) class G = E,
detail::enable_if_t<std::is_constructible<E, G &&>::value> * = nullptr,
detail::enable_if_t<!std::is_convertible<G &&, E>::value> * = nullptr>
explicit constexpr expected(unexpected<G> &&e) noexcept(
std::is_nothrow_constructible<E, G &&>::value)
: storage_base(unexpect, std::move(e)) {} : storage_base(unexpect, std::move(e)) {}
template <class G = E, detail::enable_if_t<std::is_constructible<E, G&&>::value>* = nullptr, detail::enable_if_t<std::is_convertible<G&&, E>::value>* = nullptr> template <
constexpr expected(unexpected<G> && e) noexcept(std::is_nothrow_constructible<E, G&&>::value) class G = E,
detail::enable_if_t<std::is_constructible<E, G &&>::value> * = nullptr,
detail::enable_if_t<std::is_convertible<G &&, E>::value> * = nullptr>
constexpr expected(unexpected<G> &&e) noexcept(
std::is_nothrow_constructible<E, G &&>::value)
: storage_base(unexpect, std::move(e)) {} : storage_base(unexpect, std::move(e)) {}
template <class... Args, detail::enable_if_t<std::is_constructible<E, Args&&...>::value>* = nullptr> template <class... Args,
constexpr explicit expected(unexpect_t, Args&&... args) detail::enable_if_t<std::is_constructible<E, Args &&...>::value> * =
nullptr>
constexpr explicit expected(unexpect_t, Args &&... args)
: storage_base(unexpect, std::forward<Args>(args)...) {} : storage_base(unexpect, std::forward<Args>(args)...) {}
template <class U, class... Args, detail::enable_if_t<std::is_constructible<E, std::initializer_list<U>&, Args&&...>::value>* = nullptr> template <class U, class... Args,
constexpr explicit expected(unexpect_t, std::initializer_list<U> il, Args&&... args) detail::enable_if_t<std::is_constructible<
E, std::initializer_list<U> &, Args &&...>::value> * = nullptr>
constexpr explicit expected(unexpect_t, std::initializer_list<U> il,
Args &&... args)
: storage_base(unexpect, il, std::forward<Args>(args)...) {} : storage_base(unexpect, il, std::forward<Args>(args)...) {}
constexpr expected(const expected& rhs) { constexpr expected(const expected &rhs) {
if (rhs.has_value()) { if (rhs.has_value()) {
::new (valptr()) T (*rhs); ::new (valptr()) T(*rhs);
} } else {
else { ::new (errptr()) unexpected_type(unexpected<E>(rhs.error()));
::new (errptr()) unexpected_type (unexpected<E>(rhs.error()));
} }
} }
//TODO SFINAE // TODO SFINAE
constexpr expected(expected&& rhs) noexcept(std::is_nothrow_move_constructible<T>::value && std::is_nothrow_move_constructible<E>::value) { constexpr expected(expected &&rhs) noexcept(
std::is_nothrow_move_constructible<T>::value
&&std::is_nothrow_move_constructible<E>::value) {
if (rhs.has_value()) { if (rhs.has_value()) {
::new (valptr()) T (std::move(*rhs)); ::new (valptr()) T(std::move(*rhs));
} } else {
else { ::new (errptr()) unexpected_type(unexpected<E>(std::move(rhs.error())));
::new (errptr()) unexpected_type (unexpected<E>(std::move(rhs.error())));
} }
} }
//TODO SFINAE // TODO SFINAE
template <class U, class G, detail::enable_if_t<(!std::is_convertible<U const&, T>::value || !std::is_convertible<G const&, E>::value)>* = nullptr> template <class U, class G,
explicit constexpr expected(const expected<U, G>& rhs) { detail::enable_if_t<(!std::is_convertible<U const &, T>::value ||
!std::is_convertible<G const &, E>::value)> * =
nullptr>
explicit constexpr expected(const expected<U, G> &rhs) {
if (rhs.has_value()) { if (rhs.has_value()) {
::new (valptr()) T (*rhs); ::new (valptr()) T(*rhs);
} } else {
else { ::new (errptr()) unexpected_type(unexpected<E>(rhs.error()));
::new (errptr()) unexpected_type (unexpected<E>(rhs.error()));
} }
} }
//TODO SFINAE // TODO SFINAE
template <class U, class G, detail::enable_if_t<(!std::is_convertible<U&&, T>::value || !std::is_convertible<G&&, E>::value)>* = nullptr> template <
explicit constexpr expected(const expected<U, G>& rhs) { class U, class G,
detail::enable_if_t<(!std::is_convertible<U &&, T>::value ||
!std::is_convertible<G &&, E>::value)> * = nullptr>
explicit constexpr expected(const expected<U, G> &rhs) {
if (rhs.has_value()) { if (rhs.has_value()) {
::new (valptr()) T (*rhs); ::new (valptr()) T(*rhs);
} } else {
else { ::new (errptr()) unexpected_type(unexpected<E>(rhs.error()));
::new (errptr()) unexpected_type (unexpected<E>(rhs.error()));
} }
} }
//TODO SFINAE // TODO SFINAE
template <class U, class G, detail::enable_if_t<(std::is_convertible<U&&, T>::value || std::is_convertible<G&&, E>::value)>* = nullptr> template <
constexpr expected(expected<U, G>&& rhs) { class U, class G,
detail::enable_if_t<(std::is_convertible<U &&, T>::value ||
std::is_convertible<G &&, E>::value)> * = nullptr>
constexpr expected(expected<U, G> &&rhs) {
if (rhs.has_value()) { if (rhs.has_value()) {
::new (valptr()) T (std::move(*rhs)); ::new (valptr()) T(std::move(*rhs));
} } else {
else { ::new (errptr()) unexpected_type(unexpected<E>(std::move(rhs.error())));
::new (errptr()) unexpected_type (unexpected<E>(std::move(rhs.error())));
} }
} }
//TODO SFINAE // TODO SFINAE
template <class U = T, detail::enable_if_t<!std::is_convertible<U&&, T>::value>* = nullptr> template <class U = T, detail::enable_if_t<
explicit constexpr expected(U&& v) !std::is_convertible<U &&, T>::value> * = nullptr>
: expected(in_place, std::forward<U>(v)) explicit constexpr expected(U &&v) : expected(in_place, std::forward<U>(v)) {}
{}
//TODO SFINAE // TODO SFINAE
template <class U = T, detail::enable_if_t<std::is_convertible<U&&, T>::value>* = nullptr> template <class U = T, detail::enable_if_t<
constexpr expected(U&& v) std::is_convertible<U &&, T>::value> * = nullptr>
: expected(in_place, std::forward<U>(v)) constexpr expected(U &&v) : expected(in_place, std::forward<U>(v)) {}
{}
//TODO // TODO
expected& operator=(const expected&); expected &operator=(const expected &);
expected& operator=(expected&&) noexcept; expected &operator=(expected &&) noexcept;
template <class U = T> expected& operator=(U&&); template <class U = T> expected &operator=(U &&);
template <class G = E> template <class G = E> expected &operator=(const unexpected<G> &);
expected& operator=(const unexpected<G>&); template <class G = E> expected &operator=(unexpected<G> &&) noexcept;
template <class G = E> template <class... Args> void emplace(Args &&...);
expected& operator=(unexpected<G>&&) noexcept;
template <class... Args>
void emplace(Args&&...);
template <class U, class... Args> template <class U, class... Args>
void emplace(std::initializer_list<U>, Args&&...); void emplace(std::initializer_list<U>, Args &&...);
//TODO SFINAE // TODO SFINAE
void swap(expected& rhs) noexcept(std::is_nothrow_move_constructible<T>::value && noexcept(swap(std::declval<T&>(), std::declval<T&>())) && std::is_nothrow_move_constructible<E>::value && noexcept(swap(std::declval<E&>(), std::declval<E&>()))) void swap(expected &rhs) noexcept(
{ std::is_nothrow_move_constructible<T>::value &&noexcept(
swap(std::declval<T &>(), std::declval<T &>())) &&
std::is_nothrow_move_constructible<E>::value &&
noexcept(swap(std::declval<E &>(), std::declval<E &>()))) {
if (has_value() && rhs.has_value()) { if (has_value() && rhs.has_value()) {
using std::swap; using std::swap;
swap(val(), rhs.val()); swap(val(), rhs.val());
} } else if (!has_value() && rhs.has_value()) {
else if (!has_value() && rhs.has_value()) {
using std::swap; using std::swap;
swap(err(), rhs.err()); swap(err(), rhs.err());
} } else if (has_value()) {
else if (has_value()) {
auto temp = std::move(rhs.err()); auto temp = std::move(rhs.err());
::new (rhs.valptr()) T (val()); ::new (rhs.valptr()) T(val());
::new (errptr()) unexpected_type (std::move(temp)); ::new (errptr()) unexpected_type(std::move(temp));
std::swap(this->m_has_val, rhs.m_has_val); std::swap(this->m_has_val, rhs.m_has_val);
} } else {
else {
auto temp = std::move(this->err()); auto temp = std::move(this->err());
::new (valptr()) T (rhs.val()); ::new (valptr()) T(rhs.val());
::new (errptr()) unexpected_type (std::move(temp)); ::new (errptr()) unexpected_type(std::move(temp));
std::swap(this->m_has_val, rhs.m_has_val); std::swap(this->m_has_val, rhs.m_has_val);
} }
} }
constexpr const T* operator ->() const { return valptr(); } constexpr const T *operator->() const { return valptr(); }
constexpr T* operator ->() { return valptr(); } constexpr T *operator->() { return valptr(); }
constexpr const T& operator *() const& { return val(); } constexpr const T &operator*() const & { return val(); }
constexpr T& operator *() & { return val(); } constexpr T &operator*() & { return val(); }
constexpr const T&& operator *() const && { return std::move(val()); } constexpr const T &&operator*() const && { return std::move(val()); }
constexpr T&& operator *() && { return std::move(val()); } constexpr T &&operator*() && { return std::move(val()); }
constexpr explicit operator bool() const noexcept { return this->m_has_val; } constexpr explicit operator bool() const noexcept { return this->m_has_val; }
constexpr bool has_value() const noexcept { return this->m_has_val; } constexpr bool has_value() const noexcept { return this->m_has_val; }
constexpr const T& value() const& { constexpr const T &value() const & {
if (!has_value()) throw bad_expected_access<E>(err()); if (!has_value())
throw bad_expected_access<E>(err());
return val(); return val();
} }
constexpr T& value() & { constexpr T &value() & {
if (!has_value()) throw bad_expected_access<E>(err()); if (!has_value())
throw bad_expected_access<E>(err());
return val(); return val();
} }
constexpr const T&& value() const && { constexpr const T &&value() const && {
if (!has_value()) throw bad_expected_access<E>(err()); if (!has_value())
throw bad_expected_access<E>(err());
return std::move(val()); return std::move(val());
} }
constexpr T&& value() && { constexpr T &&value() && {
if (!has_value()) throw bad_expected_access<E>(err()); if (!has_value())
throw bad_expected_access<E>(err());
return std::move(val()); return std::move(val());
} }
constexpr const E& error() const& { return err().value(); } constexpr const E &error() const & { return err().value(); }
constexpr E& error() & { return err().value(); } constexpr E &error() & { return err().value(); }
constexpr const E&& error() const && { return std::move(err().value()); } constexpr const E &&error() const && { return std::move(err().value()); }
constexpr E&& error() && { return std::move(err().value()); } constexpr E &&error() && { return std::move(err().value()); }
template <class U> template <class U> constexpr T value_or(U &&v) const & {
constexpr T value_or(U&& v) const& { static_assert(std::is_copy_constructible<T>::value &&
static_assert(std::is_copy_constructible<T>::value && std::is_convertible<U&&, T>::value, "T must be copy-constructible and convertible to from U&&"); std::is_convertible<U &&, T>::value,
"T must be copy-constructible and convertible to from U&&");
return bool(*this) ? **this : static_cast<T>(std::forward<U>(v)); return bool(*this) ? **this : static_cast<T>(std::forward<U>(v));
} }
template <class U> template <class U> T value_or(U &&v) && {
T value_or(U&& v) && { static_assert(std::is_move_constructible<T>::value &&
static_assert(std::is_move_constructible<T>::value && std::is_convertible<U&&, T>::value, "T must be move-constructible and convertible to from U&&"); std::is_convertible<U &&, T>::value,
"T must be move-constructible and convertible to from U&&");
return bool(*this) ? std::move(**this) : static_cast<T>(std::forward<U>(v)); return bool(*this) ? std::move(**this) : static_cast<T>(std::forward<U>(v));
} }
}; };
// TODO
template <class E> class expected<void, E> {};
//TODO
template <class E>
class expected<void, E> {
};
template <class T, class E>
constexpr bool operator==(const expected<T, E>& lhs, const expected<T, E>& rhs) {
return (lhs.has_value() != rhs.has_value()) ? false :
(!lhs.has_value() ? lhs.error() == rhs.error()
: *lhs == *rhs);
}
template <class T, class E> template <class T, class E>
constexpr bool operator!=(const expected<T, E>& lhs, const expected<T, E>& rhs) { constexpr bool operator==(const expected<T, E> &lhs,
return (lhs.has_value() != rhs.has_value()) ? true : const expected<T, E> &rhs) {
(!lhs.has_value() ? lhs.error() != rhs.error() return (lhs.has_value() != rhs.has_value())
: *lhs != *rhs); ? false
: (!lhs.has_value() ? lhs.error() == rhs.error() : *lhs == *rhs);
}
template <class T, class E>
constexpr bool operator!=(const expected<T, E> &lhs,
const expected<T, E> &rhs) {
return (lhs.has_value() != rhs.has_value())
? true
: (!lhs.has_value() ? lhs.error() != rhs.error() : *lhs != *rhs);
} }
template <class T, class E> template <class T, class E>
constexpr bool operator==(const expected<T, E>& x, const T& v) { constexpr bool operator==(const expected<T, E> &x, const T &v) {
return x.has_value() ? *x == v : false; return x.has_value() ? *x == v : false;
} }
template <class T, class E> template <class T, class E>
constexpr bool operator==(const T& v, const expected<T, E>& x) { constexpr bool operator==(const T &v, const expected<T, E> &x) {
return x.has_value() ? *x == v : false; return x.has_value() ? *x == v : false;
} }
template <class T, class E> template <class T, class E>
constexpr bool operator!=(const expected<T, E>& x, const T& v) { constexpr bool operator!=(const expected<T, E> &x, const T &v) {
return x.has_value() ? *x != v : true; return x.has_value() ? *x != v : true;
} }
template <class T, class E> template <class T, class E>
constexpr bool operator!=(const T& v, const expected<T, E>& x) { constexpr bool operator!=(const T &v, const expected<T, E> &x) {
return x.has_value() ? *x != v : true; return x.has_value() ? *x != v : true;
} }
template <class T, class E> template <class T, class E>
constexpr bool operator==(const expected<T, E>& x, const unexpected<E>& e) { constexpr bool operator==(const expected<T, E> &x, const unexpected<E> &e) {
return x.has_value() ? true : x.error() == e.value(); return x.has_value() ? true : x.error() == e.value();
} }
template <class T, class E> template <class T, class E>
constexpr bool operator==(const unexpected<E>& e, const expected<T, E>& x) { constexpr bool operator==(const unexpected<E> &e, const expected<T, E> &x) {
return x.has_value() ? true : x.error() == e.value(); return x.has_value() ? true : x.error() == e.value();
} }
template <class T, class E> template <class T, class E>
constexpr bool operator!=(const expected<T, E>& x, const unexpected<E>& e) { constexpr bool operator!=(const expected<T, E> &x, const unexpected<E> &e) {
return x.has_value() ? false : x.error() != e.value(); return x.has_value() ? false : x.error() != e.value();
} }
template <class T, class E> template <class T, class E>
constexpr bool operator!=(const unexpected<E>& e, const expected<T, E>& x) { constexpr bool operator!=(const unexpected<E> &e, const expected<T, E> &x) {
return x.has_value() ? false : x.error() != e.value(); return x.has_value() ? false : x.error() != e.value();
} }
// TODO is_swappable
//TODO is_swappable template <class T, class E,
template <class T, class E, detail::enable_if_t<std::is_move_constructible<T>::value && std::is_move_constructible<E>::value>* = nullptr> detail::enable_if_t<std::is_move_constructible<T>::value &&
void swap(expected<T, E>& lhs, expected<T, E>& rhs) noexcept(noexcept(lhs.swap(rhs))) { std::is_move_constructible<E>::value> * = nullptr>
void swap(expected<T, E> &lhs,
expected<T, E> &rhs) noexcept(noexcept(lhs.swap(rhs))) {
lhs.swap(rhs); lhs.swap(rhs);
} }
} } // namespace tl
#endif #endif