Struct CurrentPrevious 

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

Implementations

impl<T> CurrentPrevious<T>

pub fn new(initial: T) -> Self

Creates a new CurrentPrevious holding the initial value as its current value. The previous value is initially None.

Examples

let current_previous = CurrentPrevious::new(0);

assert_eq!(current_previous.current(), &0);
assert_eq!(current_previous.previous(), None);

pub fn current(&self) -> &T

Gets a reference to the current value.

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

Gets an optional reference to the previous value.

pub fn update(&mut self, new: T)

Sets a new current value, replacing the previous value with the old current value.

Examples

let mut current_previous = CurrentPrevious::new(0);

assert_eq!(current_previous.current(), &0);
assert_eq!(current_previous.previous(), None);

current_previous.update(1);

assert_eq!(current_previous.current(), &1);
assert_eq!(current_previous.previous(), Some(&0));

pub fn reset(&mut self, new: T)

Replaces self with a new CurrentPrevious constructed from the given new value.

Examples

let mut current_previous = CurrentPrevious::new(0);

assert_eq!(current_previous.current(), &0);
assert_eq!(current_previous.previous(), None);

current_previous.reset(1);

assert_eq!(current_previous.current(), &1);
assert_eq!(current_previous.previous(), None);

pub fn clear_previous(&mut self)

Sets the previous value to None.

Examples

let mut current_previous = CurrentPrevious::new(0);

assert_eq!(current_previous.current(), &0);
assert_eq!(current_previous.previous(), None);

current_previous.update(1);

assert_eq!(current_previous.current(), &1);
assert_eq!(current_previous.previous(), Some(&0));

current_previous.clear_previous();

assert_eq!(current_previous.current(), &1);
assert_eq!(current_previous.previous(), None);

Trait Implementations

impl<T: Clone> Clone for CurrentPrevious<T>

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

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<T: Debug> Debug for CurrentPrevious<T>

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

Formats the value using the given formatter.

impl<T: Copy> Copy for CurrentPrevious<T>