UndoTracking

A closure-based wrapper for UndoManager, inspired by SwiftUI’s declarative style.

Overview

UndoTracking lets you register undo and redo actions using a closure builder. For example:

withUndoTracking(undoManager) {
    document.replace(\.selection, with: [note])
        .named("Select \(note)")
        .animated()
}

• withUndoTracking(_:) opens a builder closure that returns an UndoComponent.
• You can chain modifiers on the component:
  • named(_:) sets the undo/redo action’s name.
  • animated() marks the action to run inside a withAnimation block (when used in SwiftUI).

UndoTracking Protocol

Conform your class to UndoTracking (no requirements other than being a class) to gain a suite of built-in undo components, such as replace(_:with:), insert(_:at:), and so on. These methods return UndoComponent instances that you can use inside withUndoTracking(_:).

Creating Custom UndoComponents

To add your own undoable operations, return an UndoComponent from a method on your UndoTracking type:

final class Counter: UndoTracking {
    var count: Int = 0

    func increment() -> UndoComponent<Counter> {
        UndoComponent(target: self) { target, withAnimation, registerUndo in
            // Primary action
            withAnimation {
                target.count += 1
            }
            // Register the inverse action
            registerUndo {
                target.decrement()
            }
        }
    }

    func decrement() -> UndoComponent<Counter> { ... }
}

Closure Parameters

• target: The instance on which the action is performed.
• withAnimation: A closure that runs its block with animation if animated() was called. You can ignore it if you don’t need animation.
• registerUndo: A closure that takes a zero-argument function—in it, register the inverse operation to be executed on undo.

Modifiers applied to the returned UndoComponent (like named or animated) are preserved when the component is executed.

Getting Started

UndoTracking uses Swift Package Manager as its build tool. If you want to import in your own project, it's as simple as adding a dependencies clause to your Package.swift:

dependencies: [
    .package(url: "https://github.com/Vaida12345/UndoTracking.git", from: "1.0.0")
]

and then adding the appropriate module to your target dependencies.

Using Xcode Package support

You can add this framework as a dependency to your Xcode project by clicking File -> Swift Packages -> Add Package Dependency. The package is located at:

https://github.com/Vaida12345/UndoTracking.git

Documentation

This package uses DocC for documentation.