fgmnt::figment< T > Union Template Reference

A figment holds either an object or nothing. More...

Public Types
using	value_type = T
	Underlying object type.

Public Member Functions
constexpr	figment ()
	Does nothing. You have to initialize the underlying object manually.
constexpr	~figment ()
	Does nothing. You have to destroy the underlying object manually.
template<typename... Args>
constexpr	figment (Args &&...args)
	Starts the lifetime of the underlying object. More...
template<typename U >
constexpr	figment (std::initializer_list< U > list)
	Starts the lifetime of the underlying object. More...
template<typename... Args>
void	create (Args &&...args)
	Starts the lifetime of the underlying object. More...
template<typename U >
void	create (std::initializer_list< U > list)
	Starts the lifetime of the underlying object. More...
constexpr void	destroy ()
	Destroys the underlying object, ending its lifetime.
template<typename... Args>
constexpr void	replace (Args &&...args)
	Replaces the underlying object. More...
template<typename U >
constexpr void	replace (std::initializer_list< U > list)
	Replaces the underlying object. More...
constexpr T &	to_underlying ()
	Accessor to the underlying object.
constexpr const T &	to_underlying () const
	Accessor to the underlying object, as if it were of type std::add_const_t<T>.
constexpr decltype(auto)	begin ()
	Same as calling std::begin with the underlying object.
constexpr decltype(auto)	begin () const
	Same as calling std::begin with the underlying object, as if it were of type std::add_const_t<T>.
constexpr decltype(auto)	end ()
	Same as calling std::end with the underlying object.
constexpr decltype(auto)	end () const
	Same as calling std::end with the underlying object, as if it were of type std::add_const_t<T>.
constexpr T *	operator-> ()
	Accesses the members of the underlying object.
constexpr const T *	operator-> () const
	Accesses the members of the underlying object, as if it were of type std::add_const_t<T>.
constexpr decltype(auto)	operator& ()
	Same as using the & operator in the underlying object.
constexpr decltype(auto)	operator& () const
	Same as using the & operator in the underlying object, as if it were of type std::add_const_t<T>.
template<typename Arg >
constexpr decltype(auto)	operator[] (Arg &&rhs)
	Same as using the [] operator in the underlying object.
template<typename Arg >
constexpr decltype(auto)	operator[] (Arg &&rhs) const
	Same as using the [] operator in the underlying object, as if it were of type std::add_const_t<T>.
template<typename Arg >
constexpr decltype(auto)	operator= (Arg &&rhs)
	Same as using the = operator in the underlying object.
template<typename Arg >
constexpr decltype(auto)	operator= (Arg &&rhs) const
	Same as using the = operator in the underlying object, as if it were of type std::add_const_t<T>.
template<typename Arg >
constexpr decltype(auto)	operator<=> (Arg &&rhs)
	Same as using the <=> operator in the underlying object.
template<typename Arg >
constexpr decltype(auto)	operator<=> (Arg &&rhs) const
	Same as using the <=> operator in the underlying object, as if it were of type std::add_const_t<T>.
template<typename Arg >
constexpr bool	operator== (Arg &&rhs)
	Same as using the == operator in the underlying object.
template<typename Arg >
constexpr bool	operator== (Arg &&rhs) const
	Same as using the == operator in the underlying object, as if it were of type std::add_const_t<T>.
constexpr	operator T& ()
	Returns a reference to the underlying object.
constexpr	operator const T & () const
	Returns a const reference to the underlying object.

Detailed Description

template<typename T>
requires (!std::is_reference_v<T> && !std::is_volatile_v<T>)
union fgmnt::figment< T >

A figment holds either an object or nothing.

Holds no information whatsoever about whether or not an object is currently stored. Only use this class if the accessor code is unreachable under unsafe conditions. Managing the underlying objects' lifetime is your responsibility.

If you need a boolean flag to track the state of a figment, this isn't for you. Use an std::optional instead.

There's not much point in using a const figment. You can use a const T, or temporarily call T's const member functions using std::as_const on the figment.

Template Parameters

T	Type of the underlying object

Constructor & Destructor Documentation

figment() [1/2]

template<typename T >

template<typename... Args>

constexpr fgmnt::figment< T >::figment ( Args &&...  args )

inlineconstexpr

Starts the lifetime of the underlying object.

Parameters

args	Arguments to initialize the object with, as if by calling T's constructor.

figment() [2/2]

template<typename T >

template<typename U >

constexpr fgmnt::figment< T >::figment ( std::initializer_list< U >  list )

inlineexplicitconstexpr

Starts the lifetime of the underlying object.

Parameters

list	Initializer list to initialize the object with, as if by calling the constructor T::T(std::initializer_list).

Member Function Documentation

create() [1/2]

template<typename T >

template<typename... Args>

void fgmnt::figment< T >::create ( Args &&...  args )

inline

Starts the lifetime of the underlying object.

The behavior is undefined if an object already exists. End its lifetime with destroy().

Parameters

args	Arguments to initialize the object with, as if by calling T's constructor.

create() [2/2]

template<typename T >

template<typename U >

void fgmnt::figment< T >::create ( std::initializer_list< U >  list )

inline

Starts the lifetime of the underlying object.

The behavior is undefined if an object already exists. End its lifetime with destroy().

Parameters

list	Initializer list to initialize the object with, as if by calling the constructor T::T(std::initializer_list).

replace() [1/2]

template<typename T >

template<typename... Args>

constexpr void fgmnt::figment< T >::replace ( Args &&...  args )

inlineconstexpr

Replaces the underlying object.

Calls T's destructor on the object, and creates another object as if using create().

The behavior is undefined if there's no underlying object

Parameters

args	Arguments to initialize the new object with, as if by calling T's constructor.

replace() [2/2]

template<typename T >

template<typename U >

constexpr void fgmnt::figment< T >::replace ( std::initializer_list< U >  list )

inlineconstexpr

Replaces the underlying object.

Calls T's destructor on the object, and creates another object as if using create().

The behavior is undefined if there's no underlying object

Parameters

list	Initializer list to initialize the new object with, as if by calling the constructor T::T(std::initializer_list).