Overview

template<typename... Types>
class pw::OptionalTuple< Types >

Tuple class with optional elements. Equivalent to std::tuple<std::optional<Types>...>, but much more efficient. Field presence is tracked by a single pw::BitSet, so the tuple elements are packed equivalently to std::tuple<Types...>.

Tuple elements are specified by their index. Elements may also be referenced by type, if there is only one instance of that type in the tuple.

Compatible with std::tuple_element and std::tuple_size.

Note: Like std::optional, moving an element out of an OptionalTuple leaves the element in an active but moved state (has_value<>() returns true). Call reset() to remove the element.

Public Member Functions
constexpr	OptionalTuple ()
	Default constructs an `OptionalTuple` with all elements unset.

template<typename... Args, typename = std::enable_if_t< (std::is_constructible_v<containers::internal::Maybe<Types>, Args> && ...) && (sizeof...(Types) != 1 \|\| (!containers::internal::IsOptionalTuple< cpp20::remove_cvref_t<Args>>::value && ...))>>
constexpr	OptionalTuple (Args &&... args)

constexpr	OptionalTuple (const OptionalTuple &other)
	Copy constructs from another `OptionalTuple`.

constexpr OptionalTuple &	operator= (const OptionalTuple &other)
	Copy assigns this from another `OptionalTuple`.

constexpr	OptionalTuple (OptionalTuple &&other)
	Move constructs from another `OptionalTuple`.

constexpr OptionalTuple &	operator= (OptionalTuple &&other)
	Move assigns this from another `OptionalTuple`.

	~OptionalTuple ()
	Destroys the `OptionalTuple` and all its active elements.

constexpr bool	empty () const
	Checks if the `OptionalTuple` contains no active elements.

constexpr size_t	count () const
	Returns the number of active elements in the `OptionalTuple`.

constexpr size_t	size () const

template<size_t kIndex>
constexpr bool	has_value () const
	Checks if the element at `kIndex` has a value.

template<typename T >
constexpr bool	has_value () const
	Checks if the element of type `T` has a value.

template<size_t kIndex>
constexpr Element< kIndex > &	value () &

template<size_t kIndex>
constexpr const Element< kIndex > &	value () const &

template<size_t kIndex>
constexpr Element< kIndex > &&	value () &&

template<size_t kIndex>
constexpr const Element< kIndex > &&	value () const &&

template<typename T >
constexpr ElementByType< T > &	value () &

template<typename T >
constexpr const ElementByType< T > &	value () const &

template<typename T >
constexpr ElementByType< T > &&	value () &&

template<typename T >
constexpr const ElementByType< T > &&	value () const &&

template<size_t kIndex, int... kExplicitGuard, typename U >
constexpr Element< kIndex >	value_or (U &&default_value) const &

template<typename T , int... kExplicitGuard, typename U >
constexpr ElementByType< T >	value_or (U &&default_value) const &

template<size_t kIndex, int... kExplicitGuard, typename U >
constexpr Element< kIndex >	value_or (U &&default_value) &&

template<typename T , int... kExplicitGuard, typename U >
constexpr ElementByType< T >	value_or (U &&default_value) &&

template<size_t kIndex, int... kExplicitGuard, typename... Args>
constexpr Element< kIndex > &	emplace (Args &&... args)

template<typename T , int... kExplicitGuard, typename... Args>
constexpr ElementByType< T > &	emplace (Args &&... args)

template<size_t kIndex>
constexpr void	reset ()
	Resets (clears) the value at the specified index, if any.

template<typename T >
constexpr void	reset ()
	Resets (clears) the value of type `T`, if any.

Constructor & Destructor Documentation

◆ OptionalTuple()

template<typename... Types>

template<typename... Args, typename = std::enable_if_t< (std::is_constructible_v<containers::internal::Maybe<Types>, Args> && ...) && (sizeof...(Types) != 1 || (!containers::internal::IsOptionalTuple< cpp20::remove_cvref_t<Args>>::value && ...))>>

constexpr pw::OptionalTuple< Types >::OptionalTuple ( Args &&... args )

inlineconstexpr

Constructs an OptionalTuple, forwarding each argument to its corresponding element. Pass pw::kTupleNull to skip initializing an element.

Member Function Documentation

◆ emplace() [1/2]

template<typename... Types>

template<size_t kIndex, int... kExplicitGuard, typename... Args>

constexpr Element< kIndex > & pw::OptionalTuple< Types >::emplace ( Args &&... args )

inlineconstexpr

Constructs an element in place and marks it active. Destroys the previous value, if any.

Returns: A reference to the newly initialized item.

◆ emplace() [2/2]

template<typename... Types>

template<typename T , int... kExplicitGuard, typename... Args>

constexpr ElementByType< T > & pw::OptionalTuple< Types >::emplace ( Args &&... args )

inlineconstexpr

Constructs an element of type T in place and marks it active. Destroys the previous value, if any.

Returns: A reference to the newly initialized item.

◆ size()

template<typename... Types>

constexpr size_t pw::OptionalTuple< Types >::size ( ) const

inlineconstexpr

Returns the total number elements in the OptionalTuple. Equivalent to std::tuple_size<>.

◆ value() [1/8]

template<typename... Types>

template<size_t kIndex>

constexpr Element< kIndex > & pw::OptionalTuple< Types >::value ( ) &

inlineconstexpr

Returns a reference to the element at kIndex.

Precondition: has_value<kIndex> must be true.

◆ value() [2/8]

template<typename... Types>

template<typename T >

constexpr ElementByType< T > & pw::OptionalTuple< Types >::value ( ) &

inlineconstexpr

Returns a reference to the element of type T.

Precondition: has_value<T> must be true.

◆ value() [3/8]

template<typename... Types>

template<size_t kIndex>

constexpr Element< kIndex > && pw::OptionalTuple< Types >::value ( ) &&

inlineconstexpr

Returns an rvalue reference to the element at kIndex.

Precondition: has_value<kIndex> must be true.

◆ value() [4/8]

template<typename... Types>

template<typename T >

constexpr ElementByType< T > && pw::OptionalTuple< Types >::value ( ) &&

inlineconstexpr

Returns an rvalue reference to the element of type T.

Precondition: has_value<T> must be true.

◆ value() [5/8]

template<typename... Types>

template<size_t kIndex>

constexpr const Element< kIndex > & pw::OptionalTuple< Types >::value ( ) const &

inlineconstexpr

Returns a const reference to the element at kIndex.

Precondition: has_value<kIndex> must be true.

◆ value() [6/8]

template<typename... Types>

template<typename T >

constexpr const ElementByType< T > & pw::OptionalTuple< Types >::value ( ) const &

inlineconstexpr

Returns a const reference to the element of type T.

Precondition: has_value<T> must be true.

◆ value() [7/8]

template<typename... Types>

template<size_t kIndex>

constexpr const Element< kIndex > && pw::OptionalTuple< Types >::value ( ) const &&

inlineconstexpr

Returns a const rvalue reference to the element at kIndex.

Precondition: has_value<kIndex> must be true.

◆ value() [8/8]

template<typename... Types>

template<typename T >

constexpr const ElementByType< T > && pw::OptionalTuple< Types >::value ( ) const &&

inlineconstexpr

Returns a const rvalue reference to the element of type T.

Precondition: has_value<T> must be true.

◆ value_or() [1/4]

template<typename... Types>

template<size_t kIndex, int... kExplicitGuard, typename U >

constexpr Element< kIndex > pw::OptionalTuple< Types >::value_or ( U && default_value ) &&

inlineconstexpr

Moves and returns the element at the specified index, if present. Otherwise, returns default_value.

◆ value_or() [2/4]

template<typename... Types>

template<typename T , int... kExplicitGuard, typename U >

constexpr ElementByType< T > pw::OptionalTuple< Types >::value_or ( U && default_value ) &&

inlineconstexpr

Moves and returns the element with the specified type, if present. Otherwise, returns default_value.

◆ value_or() [3/4]

template<typename... Types>

template<size_t kIndex, int... kExplicitGuard, typename U >

constexpr Element< kIndex > pw::OptionalTuple< Types >::value_or ( U && default_value ) const &

inlineconstexpr

Returns the element at the specified index, if present. Otherwise, returns default_value.

◆ value_or() [4/4]

template<typename... Types>

template<typename T , int... kExplicitGuard, typename U >

constexpr ElementByType< T > pw::OptionalTuple< Types >::value_or ( U && default_value ) const &

inlineconstexpr

Returns the element with the specified type, if present. Otherwise, returns default_value.

The documentation for this class was generated from the following file:

pw_containers/public/pw_containers/optional_tuple.h

Overview

Public Member Functions

Constructor & Destructor Documentation

◆ OptionalTuple()

Member Function Documentation

◆ emplace() [1/2]

◆ emplace() [2/2]

◆ size()

◆ value() [1/8]

◆ value() [2/8]

◆ value() [3/8]

◆ value() [4/8]

◆ value() [5/8]

◆ value() [6/8]

◆ value() [7/8]

◆ value() [8/8]

◆ value_or() [1/4]

◆ value_or() [2/4]

◆ value_or() [3/4]

◆ value_or() [4/4]