Swift Academy · Lesson

Result<Success, Failure> Fundamentals

Creating and pattern-matching Result values for explicit error handling.

Lesson 1 of 412 steps

Result<Success, Failure> Fundamentals is a free Swift Academy lesson on CoddyKit. This is lesson 1 of 4. Any 3 lessons of this learning path are free to read in full — after that, CoddyKit PRO unlocks every lesson, plus hands-on practice with a built-in code editor and a 24/7 AI tutor. It is part of the Swift Academy learning path, and your progress syncs across the web and the CoddyKit app. The Swift Academy course includes 4 lessons in total.

Welcome

`Result` is a Swift enum with two cases — `.success` and `.failure` — providing explicit error handling without throws/catch syntax.

Declaring Result

```swift func divide(_ a: Double, by b: Double) -> Result { guard b != 0 else { return .failure(.divisionByZero) } return .success(a / b) } enum DivisionError: Error { case divisionByZero } ```

Consuming Result

```swift switch divide(10, by: 2) { case .success(let value): print("Result: \(value)") case .failure(let err): print("Error: \(err)") } ```

get() — Throws on Failure

```swift let result = divide(10, by: 0) do { let value = try result.get() // throws DivisionError } catch { print(error) } ```

Storing Results

```swift var cache: [URL: Result] = [:] cache[url] = .success(data) cache[url] = .failure(URLError(.notConnectedToInternet)) ```

Result in Async APIs

```swift func fetch(url: URL, completion: @escaping (Result) -> Void) { URLSession.shared.dataTask(with: url) { data, _, error in if let data { completion(.success(data)) } else { completion(.failure(error ?? URLError(.unknown))) } }.resume() } ```

Pattern Matching with if case

```swift if case .success(let data) = result { process(data) } if case .failure(let err) = result { handle(err) } ```

Success and Failure Properties

```swift let r: Result = .success(42) print(r.success) // Optional(42) — non-nil on success print(r.failure) // nil ```

Initialising from Throws

```swift let result = Result { try JSONDecoder().decode(User.self, from: data) } // .success(user) or .failure(decodingError) ```

Comparing Results

```swift let a: Result = .success(42) let b: Result = .success(42) // Cannot == directly unless Success/Failure are Equatable ```

Quick Check

What does `result.get()` do when the Result is `.failure`?

Answer it in the interactive lesson

Recap

Key takeaways: • `Result` — explicit success/failure without throws • `.success(value)` / `.failure(error)` — two cases • `.get()` throws on failure • `Result { try ... }` bridges throwing code • Useful for storing/passing deferred results Next: map and flatMap on Result.

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Frequently Asked Questions

Is the “Result<Success, Failure> Fundamentals” lesson free?

Yes — any 3 lessons of the Swift Academy learning path, including “Result<Success, Failure> Fundamentals”, are free to read in full here on the web. After that, CoddyKit PRO unlocks every lesson, plus interactive practice with a built-in code editor and a 24/7 AI tutor. The Swift Academy course includes 4 lessons in total.

What will I learn in “Result<Success, Failure> Fundamentals”?

Creating and pattern-matching Result values for explicit error handling. You practise Swift Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.

Do I need any experience to start Swift Academy?

No prior experience is required. Swift Academy on CoddyKit is structured for beginners through advanced learners, so you can start here or from the beginning and move at your own pace. This is lesson 1 of 4.

How long does the “Result<Success, Failure> Fundamentals” lesson take?

Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.

Can I write and run code in this Swift Academy lesson?

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