Struct OptionalCell

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

OptionalCell is a Cell that wraps an Option. This is helper type that makes keeping types that can be None a little cleaner.

Implementations

impl<T> OptionalCell<T>

pub const fn new(val: T) -> OptionalCell<T>

Create a new OptionalCell.

pub const fn empty() -> OptionalCell<T>

Create an empty OptionalCell (contains just None).

pub fn set(&self, val: T)

Update the stored value.

pub fn insert(&self, opt: Option<T>)

Insert the value of the supplied Option, or None if the supplied Option is None.

pub fn replace(&self, val: T) -> Option<T>

Replace the contents with the supplied value. If the cell was not empty, the previous value is returned, otherwise None is returned.

pub fn clear(&self)

Reset the stored value to None.

pub fn is_some(&self) -> bool

Check if the cell contains something.

pub fn is_none(&self) -> bool

Check if the cell is None.

pub fn contains(&self, x: &T) -> bool

where T: PartialEq,

Returns true if the option is a Some value containing the given value.

pub fn ok_or<E>(self, err: E) -> Result<T, E>

Transforms the contained Option<T> into a Result<T, E>, mapping Some(v) to Ok(v) and None to Err(err).

Arguments passed to ok_or are eagerly evaluated; if you are passing the result of a function call, it is recommended to use ok_or_else, which is lazily evaluated.

pub fn ok_or_else<E, F>(self, err: F) -> Result<T, E>

where F: FnOnce() -> E,

Transforms the contained Option<T> into a Result<T, E>, mapping Some(v) to Ok(v) and None to Err(err).

pub fn and<U>(self, optb: Option<U>) -> Option<U>

Returns None if the option is None, otherwise returns optb.

pub fn filter<P>(self, predicate: P) -> Option<T>

where P: FnOnce(&T) -> bool,

Returns None if the option is None, otherwise calls predicate with the wrapped value and returns:

• Some(t) if predicate returns true (where t is the wrapped value), and
• None if predicate returns false.

pub fn or(self, optb: Option<T>) -> Option<T>

Returns the option if it contains a value, otherwise returns optb.

Arguments passed to or are eagerly evaluated; if you are passing the result of a function call, it is recommended to use or_else, which is lazily evaluated.

pub fn or_else<F>(self, f: F) -> Option<T>

where F: FnOnce() -> Option<T>,

Returns the option if it contains a value, otherwise calls f and returns the result.

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

Return the contained value and replace it with None.

pub fn unwrap_or_default(self) -> T

where T: Default,

Returns the contained value or a default

Consumes the self argument then, if Some, returns the contained value, otherwise if None, returns the default value for that type.

impl<T: Copy> OptionalCell<T>

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

Returns a copy of the contained Option.

pub fn unwrap_or_panic(&self) -> T

Returns the contained value or panics if contents is None. We do not use the traditional name for this function – unwrap() – because the Tock kernel discourages panicking, and this name is intended to discourage users from casually adding calls to unwrap() without careful consideration.

pub fn unwrap_or(&self, default: T) -> T

Returns the contained value or a default.

pub fn unwrap_or_else<F>(&self, default: F) -> T

where F: FnOnce() -> T,

Returns the contained value or computes a default.

pub fn map<F, R>(&self, closure: F) -> Option<R>

where F: FnOnce(T) -> R,

Call a closure on the value if the value exists.

pub fn map_or<F, R>(&self, default: R, closure: F) -> R

where F: FnOnce(T) -> R,

Call a closure on the value if the value exists, or return the default if the value is None.

pub fn map_or_else<U, D, F>(&self, default: D, closure: F) -> U

where D: FnOnce() -> U, F: FnOnce(T) -> U,

If the cell contains a value, call a closure supplied with the value of the cell. If the cell contains None, call the other closure to return a default value.

pub fn and_then<U, F: FnOnce(T) -> Option<U>>(&self, f: F) -> Option<U>

If the cell is empty, return None. Otherwise, call a closure with the value of the cell and return the result.

Trait Implementations

impl<T> Default for OptionalCell<T>

fn default() -> Self

Returns an empty OptionalCell.