Tuple

C++ std::tuple manually implemented.

Implementation details

The abl::tuple container is implemented as a wrapper around a proxy struct that inherits from a pack of leaf structs, each of which holds a single value of the tuple. This makes the container occupy consecutive memory locations, allowing for efficient indexing and iteration via simple casts.

Constructors

abl::tuple provides the following constructors:

• abl::tuple(): default constructor, initializes a tuple with default-constructed values.
• abl::tuple(Args&&...): initializes the tuple with the given values.
• abl::tuple(const abl::tuple&): copy constructor, copies the tuple.
• abl::tuple(abl::tuple&&): move constructor, transfers ownership of the tuple.

Assignment operators

abl::tuple provides the following assignment operators:

• abl::tuple& operator=(const abl::tuple&): copy assignment operator, copies the tuple.
• abl::tuple& operator=(abl::tuple&&): move assignment operator, transfers ownership of the tuple.

Modifiers

abl::tuple provides the following modifiers:

• void swap(abl::tuple&): swaps the contents of the tuple with another tuple.

Accessors

abl::tuple provides the following accessors:

• T& get<I>() &: returns a reference to the value at the given index I.
• const T& get<I>() const &: returns a const reference to the value at the given index I.
• T&& get<I>() &&: returns a rvalue reference to the value at the given index I.
• const T&& get<I>() const &&: returns a const rvalue reference to the value at the given index I.

Observers

abl::tuple provides the following observers:

• static std::size_t size returns the number of elements in the tuple.

Comparison operators

abl::tuple provides the following comparison operators:

• bool operator==(const abl::tuple&): returns true if the tuples are equal.
• bool operator<=>(abl::tuple const&): a three-way comparison operator that returns 0 if the tuples are equal, 1 if the first tuple is greater, and -1 if the second tuple is greater.

Non-member functions

abl::tuple provides the following non-member functions:

• void swap(abl::tuple&, abl::tuple&): swaps the contents of two tuples.
• T& get<I>(abl::tuple&): returns a reference to the value at the given index I.
• const T& get<I>(const abl::tuple&): returns a const reference to the value at the given index I.
• T&& get<I>(abl::tuple&&): returns a rvalue reference to the value at the given index I.
• const T&& get<I>(const abl::tuple&&): returns a const rvalue reference to the value at the given index I.