punkfuncgames/undo-module

UndoModule Reference

Package: com.punkfuncgames.undo | Define: PUNKFUNC_UNDO Location: Packages/com.punkfuncgames.undo/Runtime/PunkFuncGames.Undo/ Namespace: PunkFuncGames.Undo

IUndoRedoService

State (Reactive):

• ReadOnlyReactiveProperty<int> UndoCount, RedoCount
• ReadOnlyReactiveProperty<bool> CanUndo, CanRedo
• ReadOnlyReactiveProperty<IUndoableCommand> LastCommand

Operations:

• UniTask ExecuteAsync(IUndoableCommand command, ct) — execute + push to undo stack
• UniTask UndoAsync(ct), UniTask RedoAsync(ct)
• Clear(), ClearRedoStack()

Command Interfaces

IUndoableCommand:

• string Name
• UniTask ExecuteAsync(ct), UniTask UndoAsync(ct)

IMergeableCommand : IUndoableCommand:

• bool TryMerge(IUndoableCommand other) — merge consecutive commands of same type

Implementation: UndoRedoService

Dependencies: 4 MessagePipe publishers

• LinkedList-based stacks, MaxHistorySize = 100
• Auto-detects IMergeableCommand and attempts merge with last command
• Clears redo stack on new command execution

Built-in Commands

CompositeCommand — executes multiple commands in order, undoes in reverse

CompositeCommand composite = new CompositeCommand("BatchMove",
    new MoveTransformCommand(obj, newPos),
    new SetVolumeCommand(volumeService, AudioChannel.SFX, 0.5f));

MoveTransformCommand — stores before/after position + optional rotation

new MoveTransformCommand(transform, newPosition);
new MoveTransformCommand(transform, newPosition, newRotation);

SetSettingCommand<T> — undoable ISaveService key-value change (mergeable)

new SetSettingCommand<int>(saveService, "Difficulty", newValue);

SetVolumeCommand — undoable volume change (mergeable)

new SetVolumeCommand(volumeService, AudioChannel.Music, 0.8f);

Events

| Event | Key Fields | |-------|------------| | CommandExecutedEvent | Name, Description | | UndoPerformedEvent | Name | | RedoPerformedEvent | Name | | UndoStackClearedEvent | (empty) |

Installer

UndoInstaller.Install(builder, options, Lifetime.Singleton);  // in ProjectLifetimeScope
UndoInstaller.Install(builder, options, Lifetime.Scoped);     // in child scopes
// Registers: UndoRedoService with provided lifetime, 4 event brokers

Third parameter Lifetime lifetime = Lifetime.Scoped controls the service lifetime. Use Lifetime.Singleton in ProjectLifetimeScope and Lifetime.Scoped in MainMenuLifetimeScope/GameplayLifetimeScope.

Usage Pattern

// Create custom undoable command
public sealed class PlaceBuildingCommand : IUndoableCommand
{
    public string Name => "Place Building";
    private readonly IBuildingService _service;
    private readonly BuildingData _data;
    private string _placedId;

    public PlaceBuildingCommand(IBuildingService service, BuildingData data)
    { _service = service; _data = data; }

    public UniTask ExecuteAsync(CancellationToken ct)
    { _placedId = _service.Place(_data); return UniTask.CompletedTask; }

    public UniTask UndoAsync(CancellationToken ct)
    { _service.Remove(_placedId); return UniTask.CompletedTask; }
}

// Execute
await _undoRedoService.ExecuteAsync(new PlaceBuildingCommand(buildingService, data), ct);

// Bind UI
_undoRedoService.CanUndo.Subscribe(can => _undoButton.interactable = can).AddTo(_disposables);