Struct History 

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

A browser-style linear trail with a current entry.

Entries before the current one can be revisited with back, and entries left behind by going back can be restored with forward. Pushing after going back starts a new branch and drops the forward entries.

Implementations

impl<T> History<T>

pub fn new() -> Self

pub fn max_entries(self, max_entries: usize) -> Self

Sets the maximum number of root-to-current entries to keep, defaults to 1000.

Lowering the limit immediately removes the oldest entries.

pub fn push(&mut self, entry: T)

Pushes an entry and drops the forward branch.

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

Returns the current entry.

pub fn replace_current(&mut self, entry: T)

Replaces the current entry, or pushes when the trail is empty.

pub fn remove_current(&mut self) -> Option<T>

Removes and returns the current entry without changing the forward branch.

pub fn can_back(&self) -> bool

Returns whether moving back would keep a root entry current.

pub fn can_forward(&self) -> bool

Returns whether a forward entry is available.

pub fn back(&mut self) -> Option<T>

where T: Clone,

Moves back one entry and returns the new current entry.

pub fn forward(&mut self) -> Option<T>

where T: Clone,

Moves forward one entry and returns the restored entry.

pub fn entries(&self) -> impl DoubleEndedIterator<Item = &T> + ExactSizeIterator

Iterates from the root entry to the current entry.

pub fn forward_entries( &self, ) -> impl DoubleEndedIterator<Item = &T> + ExactSizeIterator

Iterates from the nearest forward entry to the furthest.

pub fn retain(&mut self, keep: impl FnMut(&T) -> bool)

Keeps only entries accepted by keep on both sides of the current position.

pub fn clear(&mut self)

Clears current, back, and forward entries.

Trait Implementations

impl<T: Debug> Debug for History<T>

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

Formats the value using the given formatter.

impl<T> Default for History<T>

fn default() -> Self

Returns the “default value” for a type.