Struct UndoStack 

pub struct UndoStack { /* private fields */ }

A dual stack of edit transactions. Each transaction batches the before-state of every component it touched, so one undo reverses a whole edit and one redo reapplies it.

Implementations

impl UndoStack

pub fn new() -> Self

A fresh empty stack.

pub fn capture(&mut self, world: &World, entity: Entity, kind: SnapshotKind)

Captures an entity’s current value for kind into the open transaction, before applying the change. Call once per component about to change, then make the change, then commit.

pub fn commit(&mut self)

Closes the open transaction and pushes it onto the undo stack, clearing the redo stack since a new edit invalidates any redo history. A commit with nothing captured is a no-op.

pub fn undo(&mut self, world: &mut World) -> bool

Reverses the most recent committed transaction, restoring every component it captured and recording the current state for redo. Returns false when there is nothing to undo.

pub fn redo(&mut self, world: &mut World) -> bool

Reapplies the most recently undone transaction. Returns false when there is nothing to redo.

pub fn can_undo(&self) -> bool

Whether an undo is available.

pub fn can_redo(&self) -> bool

Whether a redo is available.

pub fn clear(&mut self)

Drops all history and any open transaction.

Trait Implementations

impl Default for UndoStack

fn default() -> UndoStack

Returns the “default value” for a type.