import { UndoableAction } from './UndoableAction';
/**
 * Tracks undoable actions. Pushing an action past the redo point discards the
 * redo branch. Capped at `maxActions` (default 1000) so long sessions don't grow
 * without bound. `onStateChanged` lets the UI enable/disable undo/redo controls.
 */
export declare class UndoStack {
    private maxActions;
    private actions;
    private pointer;
    private busy;
    onStateChanged?: () => void;
    constructor(maxActions?: number);
    get canUndo(): boolean;
    get canRedo(): boolean;
    get actionCount(): number;
    push(action: UndoableAction): void;
    undo(): void;
    redo(): void;
    clear(): void;
}