Enum Entry 

pub enum Entry<'a, T> {
    Vacant(VacantEntry<'a, T>),
    Occupied(OccupiedEntry<'a, T>),
}

&mut Option<T> with strongly typed context of whether it’s None or Some

Variants

Vacant(VacantEntry<'a, T>)

None

Occupied(OccupiedEntry<'a, T>)

Some

Implementations

impl<'a, T> Entry<'a, T>

pub fn and_modify(self, f: impl FnOnce(&mut T)) -> Self

Provides in-place mutable access to a Some before any potential inserts into the option.

pub fn insert_entry(self, value: T) -> OccupiedEntry<'a, T>

Sets the value of the option, and returns an OccupiedEntry.

pub fn or_default(self) -> &'a mut T

where T: Default,

Ensures a value is in the option by inserting the default value if None, and returns a mutable reference to that (already present or default) value.

pub fn or_insert(self, default: T) -> &'a mut T

Ensures a value is in the option by inserting default if None, and returns a mutable reference to that (already present or default) value.

pub fn or_insert_with(self, default: impl FnOnce() -> T) -> &'a mut T

Ensures a value is in the option by inserting default() if None, and returns a mutable reference to that (already present or default()) value.