Struct Transitionable

pub struct Transitionable<T>(/* private fields */);

This type can be used in places where you have an &mut T but need a T. It is similar to Option but with a more limited API that allows an optimization when the panic strategy is abort.

Implementations

impl<T> Transitionable<T>

pub const fn new(value: T) -> Self

Construct a new Transitionable.

pub fn into_inner(transitionable: Self) -> T

Deconstructs the Transitionable back into its held value.

Panics

Panics if the Transitionable is poisoned.

pub fn transition<F: FnOnce(T) -> T>( transitionable: &mut Self, f: F, ) -> &mut Self

Transition the held value by from one state to the next through the provided function.

Example

enum State { A, B }
let t = &mut Transitionable::new(State::A);
Transitionable::transition(t, |_: State| State::B);
assert!(matches!(**t, State::B));

Panics

Panics if the Transitionable is poisoned.

pub const fn is_poisoned(transitionable: &Self) -> bool

A Transitionable becomes poisoned when a panic occurs inside the function passed to Transitionable::transition. To use a Transitionable in an application that may catch and recover from panics, you can use this function to determine whether a Transitionable is poisoned. If a Transitionable is poisoned, you will have to replace it by creating a new Transitionable.

Trait Implementations

impl<T: Clone> Clone for Transitionable<T>

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

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<T: Debug> Debug for Transitionable<T>

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

Formats the value using the given formatter.

impl<T> Deref for Transitionable<T>

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

Panics

Panics if the Transitionable is poisoned.

type Target = T

The resulting type after dereferencing.

impl<T> DerefMut for Transitionable<T>

fn deref_mut(&mut self) -> &mut Self::Target

Panics

Panics if the Transitionable is poisoned.

impl<T> From<T> for Transitionable<T>

fn from(value: T) -> Self

Converts to this type from the input type.

impl<T: Hash> Hash for Transitionable<T>

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<T: Ord> Ord for Transitionable<T>

fn cmp(&self, other: &Transitionable<T>) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl<T: PartialEq> PartialEq for Transitionable<T>

fn eq(&self, other: &Transitionable<T>) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<T: PartialOrd> PartialOrd for Transitionable<T>

fn partial_cmp(&self, other: &Transitionable<T>) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl<T: Copy> Copy for Transitionable<T>

impl<T: Eq> Eq for Transitionable<T>

impl<T> StructuralPartialEq for Transitionable<T>