command_history 0.2.0

Generic immutable undo/redo ring for Dart. Type-safe CommandHistory<S> with Command<S> — maxSize cap, undo/redo labels, value equality, no Flutter dependency.

0.2.0

Breaking change: Command<S> is now abstract class (was abstract interface class). Change implements Command<S> to extends Command<S> in your command classes.

• Immutable stacks: undoStack/redoStack are now exposed via UnmodifiableListView — any attempt to mutate them throws UnsupportedError. replaceCurrent with mappers uses List.unmodifiable() for the same guarantee.
• Command labels: Command gains String? get label => null. Override it to drive CommandHistory.undoLabel / CommandHistory.redoLabel (e.g. "Undo Paint Stroke").
• Bounded history: CommandHistory.initial(state, maxSize: N) caps undo depth; oldest entry is dropped on overflow.
• Value equality: == and hashCode compare state + both stacks element-by-element, enabling use in Riverpod/BLoC state containers without spurious rebuilds and as Map keys.
• clearHistory(): resets both stacks while preserving state and maxSize — useful after a save-point event.
• toString(): CommandHistory(state: 5, undo: 2, redo: 0) for debugger output.
• Tests: 26 → 58.

0.1.0

• Initial extraction from sdraw monorepo.
• Command<S>: abstract interface for reversible state operations.
• CommandHistory<S>: generic immutable undo/redo ring.
• No Flutter dependency — pure Dart.