Struct MaybeUnset

pub struct MaybeUnset<T> { /* private fields */ }

Helper type for identifying whether a value was explicitly set or it is left default.

Implementations

impl<T> MaybeUnset<T>

pub fn new(default: T) -> Self

Create a new unset value.

pub fn new_or(default: T, value: Option<T>) -> Self

Create a new value from an Option. If it is Some, the value is considered set with the contained value. Otherwise it is considered unset with the default.

pub fn is_set(&self) -> bool

Check if this value was explicitly set.

pub fn set(&mut self, value: T)

Set this value. Explicitly.

pub fn try_set(&mut self, value: Option<T>)

Will set the value if value is Some. If value is None, the state of the object is unchanged.

pub fn set_if_unset(&mut self, value: T) -> bool

Only sets the value if the set flag is false. Returns whether a new value was set.

pub fn try_set_if_unset(&mut self, value: Option<T>) -> bool

Only sets the value if the set flag is false and value is Some. Returns whether a new value was set.

pub fn get(&self) -> &T

Get a reference to the contained value.

pub fn try_get(&self) -> Option<&T>

Will return a Some only if the value has been set.

pub fn unwrap(self) -> T

Unwrap this value from the MaybeUnset wrapper. Never panics.

pub fn map<U, P: FnOnce(T) -> U>(self, f: P) -> MaybeUnset<U>

Map this value using a function. The set flag is carried over.

impl<T: Clone> MaybeUnset<T>

pub fn get_cloned(&self) -> T

Clone the underlying value.

pub fn cloned(&self) -> Self

impl<T: Copy> MaybeUnset<T>

pub fn get_copied(&self) -> T

Copy the underlying value.

pub fn copied(&self) -> Self

Trait Implementations

impl<T> AsRef<T> for MaybeUnset<T>

fn as_ref(&self) -> &T

Converts this type into a shared reference of the (usually inferred) input type.

impl<T: Clone> Clone for MaybeUnset<T>

fn clone(&self) -> MaybeUnset<T>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T: Debug> Debug for MaybeUnset<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T: Default> Default for MaybeUnset<T>

fn default() -> Self

Returns the “default value” for a type.

impl<T> Deref for MaybeUnset<T>

type Target = T

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl From<MaybeUnset<LineType>> for AssociatedData

fn from(value: MaybeUnset<LineType>) -> Self

Converts to this type from the input type.

impl From<MaybeUnset<Style>> for AssociatedData

fn from(value: MaybeUnset<Style>) -> Self

Converts to this type from the input type.

impl From<MaybeUnset<bool>> for AssociatedData

fn from(value: MaybeUnset<bool>) -> Self

Converts to this type from the input type.

impl<T: Copy> Copy for MaybeUnset<T>