Struct UndoStack 

pub struct UndoStack<T: Clone> { /* private fields */ }

A generic undo/redo stack.

Stores snapshots of state. Calling undo moves backward through history; redo moves forward. Pushing a new item after undoing discards the redo branch.

Type parameters

T must implement Clone because the stack stores owned snapshots.

Implementations

impl<T: Clone> UndoStack<T>

pub fn new() -> Self

Create an empty undo stack.

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

Push a new state snapshot onto the stack.

Any redo history after the current position is discarded.

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

Move one step backward in history and return the state at the new position.

If already at the earliest state, returns that state again.

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

Move one step forward in history and return the state at the new position.

Returns None if already at the most recent state.

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

Return the state at the current position without changing it.

Trait Implementations

impl<T: Clone + Clone> Clone for UndoStack<T>

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

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<T: Debug + Clone> Debug for UndoStack<T>

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

Formats the value using the given formatter.

impl<T: Clone> Default for UndoStack<T>

fn default() -> Self

Returns the “default value” for a type.