Struct Nullable

Wrapper for a value type that can be assigned null, controlling the lifetime of the wrapped value.

Assembly: FlaxEngine.dll

File: Engine/Core/Types/Nullable.h

Syntax

public struct Nullable<T>

Type Parameters

T The type of the wrapped value. It must be move-constructible but does not have to be copy-constructible. Value is never reassigned.

Constructors

~Nullable()

Declaration

public ~Nullable()

Nullable()

Initializes Nullable() by setting the wrapped value to null.

Declaration

public Nullable()

Nullable(const Nullable& other)

Initializes Nullable() by copying another Nullable().

Declaration

public Nullable(const Nullable& other)

Parameters

Nullable other The wrapped value to be copied.

Type Parameters

typename U

typename

Nullable(const T& value)

Initializes Nullable() by copying the wrapped value.

<NullableBase name="value">The initial wrapped value to be copied.

Declaration

public Nullable(const T& value)

Parameters

T value

Type Parameters

typename U

typename

Nullable(Nullable&& other)

Initializes Nullable() by moving another Nullable().

Declaration

public Nullable(Nullable&& other) noexcept

Parameters

Nullable other The wrapped value to be moved.

Nullable(T&& value)

Initializes Nullable() by moving the wrapped value.

<NullableBase name="value">The initial wrapped value to be moved.

Declaration

public Nullable(T&& value) noexcept

Parameters

T value

Fields

_dummy

Declaration

public Dummy _dummy

Field Value

Dummy

_value

Declaration

public T _value

Field Value

T

Methods

GetAndReset(T& value)

Moves the wrapped value to the output parameter and sets the wrapped value to null. If the wrapped value is not valid, the behavior is undefined.

Declaration

public void GetAndReset(T& value)

Parameters

T value The output parameter that will receive the wrapped value.

Returns

void

GetValue()

Gets a const reference to the wrapped value. If the value is not valid, the behavior is undefined.

Declaration

public T GetValue() const

Returns

T Reference to the wrapped value.

GetValueOr(const T& defaultValue)

Gets a const reference to the wrapped value or a default value if the value is not valid.

Declaration

public T GetValueOr(const T& defaultValue) const

Parameters

T defaultValue

Returns

T Reference to the wrapped value or the default value.

GetValueOr(T& defaultValue)

Gets a mutable reference to the wrapped value or a default value if the value is not valid.

Declaration

public T GetValueOr(T& defaultValue) const

Parameters

T defaultValue

Returns

T Reference to the wrapped value or the default value.

HasValue()

Checks if wrapped object has a valid value.

Declaration

public bool HasValue() const

Returns

bool true if this object has a valid value; otherwise, false.

Match(ValueVisitor valueHandler, NullVisitor nullHandler)

Matches the wrapped value with a handler for the value or a handler for the null value.

Declaration

public auto Match(ValueVisitor valueHandler, NullVisitor nullHandler) const

Parameters

ValueVisitor valueHandler Value visitor handling valid nullable value.

NullVisitor nullHandler Null visitor handling invalid nullable value.

Returns

auto Result of the call of one of handlers. Handlers must share the same result type.

Type Parameters

typename ValueVisitor

typename NullVisitor

operator bool()

Explicit conversion to boolean value. Allows to check if the wrapped value is valid in if-statements without casting.

Declaration

public operator bool() const

Returns

FORCE_INLINE true if this object has a valid value, otherwise false

operator!=(const Nullable& other)

Indicates whether this instance is NOT equal to other one.

Declaration

public bool operator!=(const Nullable& other) const

Parameters

Nullable other The other object.

Returns

bool true if both values are not equal.

operator=(const Nullable& other)

Reassigns the wrapped value by copying another Nullable().

Declaration

public Nullable operator=(const Nullable& other)

Parameters

Nullable other

Returns

Nullable

Type Parameters

typename U

typename

operator=(const T& value)

Reassigns the wrapped value by copying.

Declaration

public Nullable operator=(const T& value)

Parameters

T value

Returns

Nullable

Type Parameters

typename U

typename

operator=(Nullable&& other)

Reassigns the wrapped value by moving another Nullable().

Declaration

public Nullable operator=(Nullable&& other) noexcept

Parameters

Nullable other

Returns

Nullable

operator=(T&& value)

Reassigns the wrapped value by moving.

Declaration

public Nullable operator=(T&& value) noexcept

Parameters

T value

Returns

Nullable

operator==(const Nullable& other)

Indicates whether this instance is equal to other one.

Declaration

public bool operator==(const Nullable& other) const

Parameters

Nullable other The other object.

Returns

bool true if both values are equal.

Reset()

Disposes the wrapped value and sets the wrapped value to null. If the wrapped value is not valid, does nothing.

Declaration

public void Reset()

Returns

void

SetValue(const T& value)

Sets the wrapped value by copying.

Declaration

public void SetValue(const T& value)

Parameters

T value The value to be copied.

Returns

void

Type Parameters

typename U

typename

SetValue(T&& value)

Sets the wrapped value by moving.

Declaration

public void SetValue(T&& value) noexcept

Parameters

T value The value to be moved.

Returns

void

TrySet(const T& value)

If the wrapped value is not valid, sets it by copying. Otherwise, does nothing.

Declaration

public bool TrySet(const T& value)

Parameters

T value

Returns

bool True if the wrapped value was changed, otherwise false.

Type Parameters

typename U

typename

TrySet(T&& value)

If the wrapped value is not valid, sets it by moving. Otherwise, does nothing.

Declaration

public bool TrySet(T&& value) noexcept

Parameters

T value

Returns

bool True if the wrapped value was changed, otherwise false.