Struct UndoStack 

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

Generic bounded undo/redo stack over snapshots of type T.

record pushes the pre-mutation state onto the undo side and clears any redo history (a fresh edit invalidates a previously-undone future — standard editor semantics). undo/redo take the caller’s current live state so they can push it onto the opposite side, mirroring the classic two-stack undo/redo implementation.

Implementations

impl<T> UndoStack<T>

pub fn new() -> Self

An unbounded stack — history grows until Self::clear is called.

pub fn with_limit(limit: usize) -> Self

A stack that discards its oldest entry once limit is exceeded. limit == 0 disables history: Self::record becomes a no-op and Self::undo/Self::redo always return None.

pub fn record(&mut self, before: T)

Record before — the state immediately prior to a mutation the caller is about to apply. Clears the redo side.

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

Undo one step. current is the caller’s live state — pushed onto the redo side so a following Self::redo can restore it. Returns the state to restore, or None if there’s nothing to undo.

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

Redo one step, mirroring Self::undo: current is pushed back onto the undo side.

pub fn can_undo(&self) -> bool

Whether Self::undo would return Some.

pub fn can_redo(&self) -> bool

Whether Self::redo would return Some.

pub fn clear(&mut self)

Drop all history — e.g. after loading a fresh document, where undoing past the load point makes no sense.

Trait Implementations

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

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

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

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

Formats the value using the given formatter.

impl<T> Default for UndoStack<T>

fn default() -> Self

Returns the “default value” for a type.

impl<T: Eq> Eq for UndoStack<T>

impl<T: PartialEq> PartialEq for UndoStack<T>

fn eq(&self, other: &Self) -> bool

Equality operator ==.

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

Inequality operator !=.

impl<T: PartialEq> StructuralPartialEq for UndoStack<T>