Re-enable left_opt() and right_opt() for rvalue references
This commit is contained in:
Sebastian Messmer
parent
2878313993
commit
4de6f1d8d9
|
|
@ -8,203 +8,217 @@
|
|||
|
||||
namespace cpputils {
|
||||
|
||||
template<class Left, class Right>
|
||||
class either final {
|
||||
public:
|
||||
template<class Head, class... Tail, std::enable_if_t<std::is_constructible<Left, Head, Tail...>::value && !std::is_constructible<Right, Head, Tail...>::value>* = nullptr>
|
||||
either(Head&& construct_left_head_arg, Tail&&... construct_left_tail_args) noexcept(noexcept(std::declval<either<Left, Right>>()._construct_left(std::forward<Head>(construct_left_head_arg), std::forward<Tail>(construct_left_tail_args)...)))
|
||||
: _side(Side::left) {
|
||||
_construct_left(std::forward<Head>(construct_left_head_arg), std::forward<Tail>(construct_left_tail_args)...);
|
||||
}
|
||||
template<class Left, class Right>
|
||||
class either final {
|
||||
public:
|
||||
template<class Head, class... Tail, std::enable_if_t<std::is_constructible<Left, Head, Tail...>::value && !std::is_constructible<Right, Head, Tail...>::value>* = nullptr>
|
||||
either(Head&& construct_left_head_arg, Tail&&... construct_left_tail_args) noexcept(noexcept(std::declval<either<Left, Right>>()._construct_left(std::forward<Head>(construct_left_head_arg), std::forward<Tail>(construct_left_tail_args)...)))
|
||||
: _side(Side::left) {
|
||||
_construct_left(std::forward<Head>(construct_left_head_arg), std::forward<Tail>(construct_left_tail_args)...);
|
||||
}
|
||||
|
||||
template<class Head, class... Tail, std::enable_if_t<!std::is_constructible<Left, Head, Tail...>::value && std::is_constructible<Right, Head, Tail...>::value>* = nullptr>
|
||||
either(Head&& construct_right_head_arg, Tail&&... construct_right_tail_args) noexcept(noexcept(std::declval<either<Left, Right>>()._construct_right(std::forward<Head>(construct_right_head_arg), std::forward<Tail>(construct_right_tail_args)...)))
|
||||
: _side(Side::right) {
|
||||
_construct_right(std::forward<Head>(construct_right_head_arg), std::forward<Tail>(construct_right_tail_args)...);
|
||||
}
|
||||
template<class Head, class... Tail, std::enable_if_t<!std::is_constructible<Left, Head, Tail...>::value && std::is_constructible<Right, Head, Tail...>::value>* = nullptr>
|
||||
either(Head&& construct_right_head_arg, Tail&&... construct_right_tail_args) noexcept(noexcept(std::declval<either<Left, Right>>()._construct_right(std::forward<Head>(construct_right_head_arg), std::forward<Tail>(construct_right_tail_args)...)))
|
||||
: _side(Side::right) {
|
||||
_construct_right(std::forward<Head>(construct_right_head_arg), std::forward<Tail>(construct_right_tail_args)...);
|
||||
}
|
||||
|
||||
//TODO Try allowing copy-construction when Left/Right types are std::is_convertible
|
||||
either(const either<Left, Right> &rhs) noexcept(noexcept(std::declval<either<Left, Right>>()._construct_left(rhs._left)) && noexcept(std::declval<either<Left, Right>>()._construct_right(rhs._right)))
|
||||
: _side(rhs._side) {
|
||||
if(_side == Side::left) {
|
||||
_construct_left(rhs._left);
|
||||
} else {
|
||||
_construct_right(rhs._right);
|
||||
}
|
||||
}
|
||||
|
||||
either(either<Left, Right> &&rhs) noexcept(noexcept(_construct_left(std::move(rhs._left))) && noexcept(_construct_right(std::move(rhs._right))))
|
||||
: _side(rhs._side) {
|
||||
if(_side == Side::left) {
|
||||
_construct_left(std::move(rhs._left));
|
||||
} else {
|
||||
_construct_right(std::move(rhs._right));
|
||||
}
|
||||
}
|
||||
|
||||
~either() {
|
||||
_destruct();
|
||||
}
|
||||
|
||||
//TODO Try allowing copy-assignment when Left/Right types are std::is_convertible
|
||||
either<Left, Right> &operator=(const either<Left, Right> &rhs) noexcept(noexcept(_construct_left(rhs._left)) && noexcept(_construct_right(rhs._right))) {
|
||||
_destruct();
|
||||
_side = rhs._side;
|
||||
if (_side == Side::left) {
|
||||
_construct_left(rhs._left);
|
||||
} else {
|
||||
_construct_right(rhs._right);
|
||||
}
|
||||
return *this;
|
||||
}
|
||||
|
||||
either<Left, Right> &operator=(either<Left, Right> &&rhs) noexcept(noexcept(_construct_left(std::move(rhs._left))) && noexcept(_construct_right(std::move(rhs._right)))) {
|
||||
_destruct();
|
||||
_side = rhs._side;
|
||||
if (_side == Side::left) {
|
||||
_construct_left(std::move(rhs._left));
|
||||
} else {
|
||||
_construct_right(std::move(rhs._right));
|
||||
}
|
||||
return *this;
|
||||
}
|
||||
|
||||
//TODO fold, map_left, map_right, left_or_else(val), right_or_else(val), left_or_else(func), right_or_else(func)
|
||||
|
||||
bool is_left() const noexcept {
|
||||
return _side == Side::left;
|
||||
}
|
||||
|
||||
bool is_right() const noexcept {
|
||||
return _side == Side::right;
|
||||
}
|
||||
|
||||
const Left &left() const& {
|
||||
ASSERT(is_left(), "Tried to get left side of an either which is right.");
|
||||
return _left;
|
||||
}
|
||||
Left &left() & {
|
||||
return const_cast<Left&>(const_cast<const either<Left, Right>*>(this)->left());
|
||||
}
|
||||
Left &&left() && {
|
||||
return std::move(left());
|
||||
}
|
||||
|
||||
const Right &right() const& {
|
||||
ASSERT(is_right(), "Tried to get right side of an either which is left.");
|
||||
return _right;
|
||||
}
|
||||
Right &right() & {
|
||||
return const_cast<Right&>(const_cast<const either<Left, Right>*>(this)->right());
|
||||
}
|
||||
Right &&right() && {
|
||||
return std::move(right());
|
||||
}
|
||||
|
||||
boost::optional<const Left&> left_opt() const& noexcept {
|
||||
if (_side == Side::left) {
|
||||
return _left;
|
||||
} else {
|
||||
return boost::none;
|
||||
}
|
||||
}
|
||||
boost::optional<Left&> left_opt() & noexcept {
|
||||
if (_side == Side::left) {
|
||||
return _left;
|
||||
} else {
|
||||
return boost::none;
|
||||
}
|
||||
}
|
||||
// left_opt()&& not offered because optional<Left&&> doesn't work
|
||||
|
||||
boost::optional<const Right&> right_opt() const& noexcept {
|
||||
if (_side == Side::right) {
|
||||
return _right;
|
||||
} else {
|
||||
return boost::none;
|
||||
}
|
||||
}
|
||||
boost::optional<Right&> right_opt() & noexcept {
|
||||
if (_side == Side::right) {
|
||||
return _right;
|
||||
} else {
|
||||
return boost::none;
|
||||
}
|
||||
}
|
||||
// right_opt()&& not offered because optional<Right&&> doesn't work
|
||||
|
||||
private:
|
||||
union {
|
||||
Left _left;
|
||||
Right _right;
|
||||
};
|
||||
enum class Side : uint8_t {left, right} _side;
|
||||
|
||||
explicit either(Side side) noexcept : _side(side) {}
|
||||
|
||||
template<typename... Args>
|
||||
void _construct_left(Args&&... args) noexcept(noexcept(new Left(std::forward<Args>(args)...))) {
|
||||
new(&_left)Left(std::forward<Args>(args)...);
|
||||
}
|
||||
template<typename... Args>
|
||||
void _construct_right(Args&&... args) noexcept(noexcept(new Right(std::forward<Args>(args)...))) {
|
||||
new(&_right)Right(std::forward<Args>(args)...);
|
||||
}
|
||||
void _destruct() noexcept {
|
||||
if (_side == Side::left) {
|
||||
_left.~Left();
|
||||
} else {
|
||||
_right.~Right();
|
||||
}
|
||||
}
|
||||
|
||||
template<typename Left_, typename Right_, typename... Args>
|
||||
friend either<Left_, Right_> make_left(Args&&... args) /* TODO noexcept(noexcept(std::declval<either<Left, Right>>()._construct_left(std::forward<Args>(args)...))) */;
|
||||
|
||||
template<typename Left_, typename Right_, typename... Args>
|
||||
friend either<Left_, Right_> make_right(Args&&... args) /* TODO noexcept(noexcept(std::declval<either<Left, Right>>()._construct_right(std::forward<Args>(args)...))) */;
|
||||
};
|
||||
|
||||
template<class Left, class Right>
|
||||
inline bool operator==(const either<Left, Right> &lhs, const either<Left, Right> &rhs) noexcept(noexcept(std::declval<Left>() == std::declval<Left>()) && noexcept(std::declval<Right>() == std::declval<Right>())) {
|
||||
if (lhs.is_left() != rhs.is_left()) {
|
||||
return false;
|
||||
}
|
||||
if (lhs.is_left()) {
|
||||
return lhs.left() == rhs.left();
|
||||
} else {
|
||||
return lhs.right() == rhs.right();
|
||||
}
|
||||
//TODO Try allowing copy-construction when Left/Right types are std::is_convertible
|
||||
either(const either<Left, Right> &rhs) noexcept(noexcept(std::declval<either<Left, Right>>()._construct_left(rhs._left)) && noexcept(std::declval<either<Left, Right>>()._construct_right(rhs._right)))
|
||||
: _side(rhs._side) {
|
||||
if(_side == Side::left) {
|
||||
_construct_left(rhs._left);
|
||||
} else {
|
||||
_construct_right(rhs._right);
|
||||
}
|
||||
}
|
||||
|
||||
template<class Left, class Right>
|
||||
inline bool operator!=(const either<Left, Right> &lhs, const either<Left, Right> &rhs) noexcept(noexcept(operator==(lhs, rhs))) {
|
||||
return !operator==(lhs, rhs);
|
||||
either(either<Left, Right> &&rhs) noexcept(noexcept(_construct_left(std::move(rhs._left))) && noexcept(_construct_right(std::move(rhs._right))))
|
||||
: _side(rhs._side) {
|
||||
if(_side == Side::left) {
|
||||
_construct_left(std::move(rhs._left));
|
||||
} else {
|
||||
_construct_right(std::move(rhs._right));
|
||||
}
|
||||
}
|
||||
|
||||
template<class Left, class Right>
|
||||
inline std::ostream &operator<<(std::ostream &stream, const either<Left, Right> &value) {
|
||||
if (value.is_left()) {
|
||||
stream << "Left(" << value.left() << ")";
|
||||
} else {
|
||||
stream << "Right(" << value.right() << ")";
|
||||
}
|
||||
return stream;
|
||||
}
|
||||
~either() {
|
||||
_destruct();
|
||||
}
|
||||
|
||||
template<typename Left, typename Right, typename... Args>
|
||||
inline either<Left, Right> make_left(Args&&... args) /* TODO noexcept(noexcept(std::declval<either<Left, Right>>()._construct_left(std::forward<Args>(args)...))) */ {
|
||||
either<Left, Right> result(either<Left, Right>::Side::left);
|
||||
result._construct_left(std::forward<Args>(args)...);
|
||||
return result;
|
||||
//TODO Try allowing copy-assignment when Left/Right types are std::is_convertible
|
||||
either<Left, Right> &operator=(const either<Left, Right> &rhs) noexcept(noexcept(_construct_left(rhs._left)) && noexcept(_construct_right(rhs._right))) {
|
||||
_destruct();
|
||||
_side = rhs._side;
|
||||
if (_side == Side::left) {
|
||||
_construct_left(rhs._left);
|
||||
} else {
|
||||
_construct_right(rhs._right);
|
||||
}
|
||||
return *this;
|
||||
}
|
||||
|
||||
template<typename Left, typename Right, typename... Args>
|
||||
inline either<Left, Right> make_right(Args&&... args) /* TODO noexcept(noexcept(std::declval<either<Left, Right>>()._construct_right(std::forward<Args>(args)...))) */ {
|
||||
either<Left, Right> result(either<Left, Right>::Side::right);
|
||||
result._construct_right(std::forward<Args>(args)...);
|
||||
return result;
|
||||
either<Left, Right> &operator=(either<Left, Right> &&rhs) noexcept(noexcept(_construct_left(std::move(rhs._left))) && noexcept(_construct_right(std::move(rhs._right)))) {
|
||||
_destruct();
|
||||
_side = rhs._side;
|
||||
if (_side == Side::left) {
|
||||
_construct_left(std::move(rhs._left));
|
||||
} else {
|
||||
_construct_right(std::move(rhs._right));
|
||||
}
|
||||
return *this;
|
||||
}
|
||||
|
||||
//TODO fold, map_left, map_right, left_or_else(val), right_or_else(val), left_or_else(func), right_or_else(func)
|
||||
|
||||
bool is_left() const noexcept {
|
||||
return _side == Side::left;
|
||||
}
|
||||
|
||||
bool is_right() const noexcept {
|
||||
return _side == Side::right;
|
||||
}
|
||||
|
||||
const Left &left() const& {
|
||||
ASSERT(is_left(), "Tried to get left side of an either which is right.");
|
||||
return _left;
|
||||
}
|
||||
Left &left() & {
|
||||
return const_cast<Left&>(const_cast<const either<Left, Right>*>(this)->left());
|
||||
}
|
||||
Left &&left() && {
|
||||
return std::move(left());
|
||||
}
|
||||
|
||||
const Right &right() const& {
|
||||
ASSERT(is_right(), "Tried to get right side of an either which is left.");
|
||||
return _right;
|
||||
}
|
||||
Right &right() & {
|
||||
return const_cast<Right&>(const_cast<const either<Left, Right>*>(this)->right());
|
||||
}
|
||||
Right &&right() && {
|
||||
return std::move(right());
|
||||
}
|
||||
|
||||
boost::optional<const Left&> left_opt() const& noexcept {
|
||||
if (_side == Side::left) {
|
||||
return _left;
|
||||
} else {
|
||||
return boost::none;
|
||||
}
|
||||
}
|
||||
boost::optional<Left&> left_opt() & noexcept {
|
||||
if (_side == Side::left) {
|
||||
return _left;
|
||||
} else {
|
||||
return boost::none;
|
||||
}
|
||||
}
|
||||
// warning: opposed to the other left_opt variants, this one already moves the content and returns by value.
|
||||
boost::optional<Left> left_opt() && noexcept(noexcept(boost::optional<Left>(std::move(_left)))) {
|
||||
if (_side == Side::left) {
|
||||
return std::move(_left);
|
||||
} else {
|
||||
return boost::none;
|
||||
}
|
||||
}
|
||||
|
||||
boost::optional<const Right&> right_opt() const& noexcept {
|
||||
if (_side == Side::right) {
|
||||
return _right;
|
||||
} else {
|
||||
return boost::none;
|
||||
}
|
||||
}
|
||||
boost::optional<Right&> right_opt() & noexcept {
|
||||
if (_side == Side::right) {
|
||||
return _right;
|
||||
} else {
|
||||
return boost::none;
|
||||
}
|
||||
}
|
||||
// warning: opposed to the other left_opt variants, this one already moves the content and returns by value.
|
||||
boost::optional<Right> right_opt() && noexcept(noexcept(boost::optional<Right>(std::move(_right)))) {
|
||||
if (_side == Side::right) {
|
||||
return std::move(_right);
|
||||
} else {
|
||||
return boost::none;
|
||||
}
|
||||
}
|
||||
|
||||
private:
|
||||
union {
|
||||
Left _left;
|
||||
Right _right;
|
||||
};
|
||||
enum class Side : uint8_t {left, right} _side;
|
||||
|
||||
explicit either(Side side) noexcept : _side(side) {}
|
||||
|
||||
template<typename... Args>
|
||||
void _construct_left(Args&&... args) noexcept(noexcept(new Left(std::forward<Args>(args)...))) {
|
||||
new(&_left)Left(std::forward<Args>(args)...);
|
||||
}
|
||||
template<typename... Args>
|
||||
void _construct_right(Args&&... args) noexcept(noexcept(new Right(std::forward<Args>(args)...))) {
|
||||
new(&_right)Right(std::forward<Args>(args)...);
|
||||
}
|
||||
void _destruct() noexcept {
|
||||
if (_side == Side::left) {
|
||||
_left.~Left();
|
||||
} else {
|
||||
_right.~Right();
|
||||
}
|
||||
}
|
||||
|
||||
template<typename Left_, typename Right_, typename... Args>
|
||||
friend either<Left_, Right_> make_left(Args&&... args) /* TODO noexcept(noexcept(std::declval<either<Left, Right>>()._construct_left(std::forward<Args>(args)...))) */;
|
||||
|
||||
template<typename Left_, typename Right_, typename... Args>
|
||||
friend either<Left_, Right_> make_right(Args&&... args) /* TODO noexcept(noexcept(std::declval<either<Left, Right>>()._construct_right(std::forward<Args>(args)...))) */;
|
||||
};
|
||||
|
||||
template<class Left, class Right>
|
||||
inline bool operator==(const either<Left, Right> &lhs, const either<Left, Right> &rhs) noexcept(noexcept(std::declval<Left>() == std::declval<Left>()) && noexcept(std::declval<Right>() == std::declval<Right>())) {
|
||||
if (lhs.is_left() != rhs.is_left()) {
|
||||
return false;
|
||||
}
|
||||
if (lhs.is_left()) {
|
||||
return lhs.left() == rhs.left();
|
||||
} else {
|
||||
return lhs.right() == rhs.right();
|
||||
}
|
||||
}
|
||||
|
||||
template<class Left, class Right>
|
||||
inline bool operator!=(const either<Left, Right> &lhs, const either<Left, Right> &rhs) noexcept(noexcept(operator==(lhs, rhs))) {
|
||||
return !operator==(lhs, rhs);
|
||||
}
|
||||
|
||||
template<class Left, class Right>
|
||||
inline std::ostream &operator<<(std::ostream &stream, const either<Left, Right> &value) {
|
||||
if (value.is_left()) {
|
||||
stream << "Left(" << value.left() << ")";
|
||||
} else {
|
||||
stream << "Right(" << value.right() << ")";
|
||||
}
|
||||
return stream;
|
||||
}
|
||||
|
||||
template<typename Left, typename Right, typename... Args>
|
||||
inline either<Left, Right> make_left(Args&&... args) /* TODO noexcept(noexcept(std::declval<either<Left, Right>>()._construct_left(std::forward<Args>(args)...))) */ {
|
||||
either<Left, Right> result(either<Left, Right>::Side::left);
|
||||
result._construct_left(std::forward<Args>(args)...);
|
||||
return result;
|
||||
}
|
||||
|
||||
template<typename Left, typename Right, typename... Args>
|
||||
inline either<Left, Right> make_right(Args&&... args) /* TODO noexcept(noexcept(std::declval<either<Left, Right>>()._construct_right(std::forward<Args>(args)...))) */ {
|
||||
either<Left, Right> result(either<Left, Right>::Side::right);
|
||||
result._construct_right(std::forward<Args>(args)...);
|
||||
return result;
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
|
|
|
|||
Loading…
Reference in New Issue