fcppt::optional::object< T > Class Template Reference

Detailed Description

template<typename T>
class fcppt::optional::object< T >

A class that makes values optional.

Template Parameters

T	The type to make optional, which must be CopyConstructible or Movable, Assignable or AssignMovable and complete. It therefore must also not be const.

See the module description for more information.

Public Types
typedef T	value_type
	The value type. More...
typedef T &	reference
	The non const reference type to value_type More...
typedef T const &	const_reference
	The const reference type to value_type More...

Public Member Functions
	object ()
	Constructs an empty optional. More...
	object (const_reference ref)
	Constructs an optional from a const_reference. More...
	object (T &&ref)
	Constructs an optional by moving from an rvalue reference. More...
	object (object const &other)
	Copy constructs an optional. More...
	object (object &&other) noexcept(std::is_nothrow_move_constructible< T >::value)
	Move constructs an optional. More...
object &	operator= (object const &other)
	Assigns from an optional. More...
object &	operator= (object &&other) noexcept(std::is_nothrow_move_constructible< T >::value &&std::is_nothrow_move_assignable< T >::value)
	Move assigns from an optional. More...
	~object ()
	Destroys the value, if any. More...
reference	get_unsafe ()
	Returns a reference to the current value. More...
const_reference	get_unsafe () const
	Returns a const reference to the current value. More...
bool	has_value () const
	Returns whether the optional holds a value. More...

Member Typedef Documentation

const_reference

template<typename T>

typedef T const& fcppt::optional::object< T >::const_reference

The const reference type to value_type

reference

template<typename T>

typedef T& fcppt::optional::object< T >::reference

The non const reference type to value_type

value_type

template<typename T>

typedef T fcppt::optional::object< T >::value_type

The value type.

Constructor & Destructor Documentation

object() [1/5]

template<typename T>

fcppt::optional::object< T >::object

(

)

Constructs an empty optional.

Postcondition

has_value() will be false.

object() [2/5]

template<typename T>

fcppt::optional::object< T >::object ( const_reference  ref )

explicit

Constructs an optional from a const_reference.

Constructs an optional by copying from ref.

Parameters

ref	The value to initialize the optional with

Postcondition

has_value() will be true.

object() [3/5]

template<typename T>

fcppt::optional::object< T >::object ( T &&  ref )

explicit

Constructs an optional by moving from an rvalue reference.

Constructs an optional by moving from ref

Parameters

ref	The value to move from

Postcondition

has_value() will be true

object() [4/5]

template<typename T>

fcppt::optional::object< T >::object

(

object< T > const &

other

)

Copy constructs an optional.

Constructs an optional by copying from other if other.has_value() is true. Otherwise, the new optional will have no value.

Parameters

other

The optional to copy from

object() [5/5]

template<typename T>

fcppt::optional::object< T >::object ( object< T > &&  other ) const

noexcept

Move constructs an optional.

Constructs an optional by moving from other. In any case, other will be left uninitialized.

Parameters

other

The optional to move from

~object()

template<typename T>

fcppt::optional::object< T >::~object

(

)

Destroys the value, if any.

If has_value() is true then the current value will be destroyed

Member Function Documentation

get_unsafe() [1/2]

template<typename T>

reference fcppt::optional::object< T >::get_unsafe

(

)

Returns a reference to the current value.

Warning

The behaviour is undefined if has_value() is false

get_unsafe() [2/2]

template<typename T>

const_reference fcppt::optional::object< T >::get_unsafe

(

)

const

Returns a const reference to the current value.

Warning

The behaviour is undefined if has_value() is false

has_value()

template<typename T>

bool fcppt::optional::object< T >::has_value

(

)

const

Returns whether the optional holds a value.

operator=() [1/2]

template<typename T>

object& fcppt::optional::object< T >::operator=

(

object< T > const &

other

)

Assigns from an optional.

Assigns the current value from *other if has_value() and other.has_value() are true. Otherwise, if has_value() is false, then the current value will be copy constructed from *other. Otherwise, if other.has_value() is false, then the optional will be reset.

Parameters

other

The optional to assign from

Returns

*this

operator=() [2/2]

template<typename T>

object& fcppt::optional::object< T >::operator= ( object< T > &&  other ) const &&

noexcept

Move assigns from an optional.

Moves the current value from *other if has_value() and other.has_value() are true. Otherwise, if has_value() is false, then the current value will be move constructed from *other. Otherwise, if other.has_value() is false, then the optional will be reset.

Parameters

other

The optional to move assign from

Returns

*this