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AltConf 2015: Swift Thinking
This document discusses Swift programming concepts including value types, optionals, testing, and more. It provides code examples of structs as value types and using optionals to represent missing or incorrect values. It also shows how to create a Person model and PersonViewModel, add input validation to the view model using enums and errors, and handle errors when creating a person from the view model.
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AltConf 2015: Swift Thinking
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- 2. @NatashaTheRobot • Swift Newsletter- swiftnews.curated.co • NatashaTheRobot.com
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- 6. Put Your StuffOut There
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- 10. Learning… • Value Types •Optionals?! • Testing
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- 12. • structs • enums •(tuples)
- 13. class Person { letname: String var age: Int init(name: String, age: Int) { self.name = name self.age = age } }
- 14. let taylorSwift =Person(name: "Taylor Swift", age: 25) func timeTravelToBirthdayForPerson(var person: Person) { person.age += 1 () } timeTravelToBirthdayForPerson(taylorSwift) taylorSwift.age // 26
- 15. let taylorSwift =Person(name: "Taylor Swift", age: 25) func timeTravelToBirthdayForPerson(person: Person) { person.age += 1 🎉🎂🎁🎈💥() } timeTravelToBirthdayForPerson(taylorSwift) taylorSwift.age // 26
- 16. let taylorSwift =Person(name: "Taylor Swift", age: 25) func timeTravelToBirthdayForPerson(var person: Person) { person.age += 1 🎉🎂🎁🎈💥() } timeTravelToBirthdayForPerson(taylorSwift) taylorSwift.age // 26
- 17. struct Person { letname: String var age: Int // NO INIT NEEDED }
- 18. let taylorSwift =Person(name: "Taylor Swift", age: 25) func timeTravelToBirthdayForPerson(var person: Person) { person.age += 1 () } timeTravelToBirthdayForPerson(taylorSwift) taylorSwift.age // 25
- 19. let taylorSwift =Person(name: "Taylor Swift", age: 25) func timeTravelToBirthdayForPerson(var person: Person) { person.age += 1 🎉🎂🎁🎈💥() } timeTravelToBirthdayForPerson(taylorSwift) taylorSwift.age // 25
- 20. let taylorSwift =Person(name: "Taylor Swift", age: 25) func timeTravelToBirthdayForPerson(var person: Person) { person.age += 1 🎉🎂🎁🎈💥() } timeTravelToBirthdayForPerson(taylorSwift) taylorSwift.age // 25
- 21. let taylorSwift =Person(name: "Taylor Swift", age: 25) func timeTravelToBirthdayForPerson(var person: Person) { person.age += 1 🎉🎂🎁🎈💥() } timeTravelToBirthdayForPerson(taylorSwift) taylorSwift.age // 25
- 23. @andy_matuschak • Functional SwiftConference: Functioning as a Functionalist • Realm: Controlling Complexity in Swift
- 24. –Functional Swift Book “Almostall types in Swift are value types, including arrays, dictionaries, numbers, booleans, tuples, and enums. Classes are the exception rather than the rule.”
- 25. $ grep -e"^struct " swift.md | wc -l 87 $ grep -e "^enum " swift.md | wc -l 8 $ grep -e "^class " swift.md | wc -l 4
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- 28. –Sunset Lake Software “~40%of bugs shipped to customers in the last three years would have been caught immediately by using Swift”
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- 31. struct Person { letname: String var age: Int }
- 32. struct PersonViewModel { varname: String? var age: String? }
- 33. class ViewController: UIViewController,UITextFieldDelegate { @IBOutlet weak var nameTextField: UITextField! @IBOutlet weak var ageTextField: UITextField! var personViewModel = PersonViewModel() override func viewDidLoad() { super.viewDidLoad() } func textFieldDidEndEditing(textField: UITextField) { personViewModel.name = nameTextField.text personViewModel.age = ageTextField.text } }
- 34. struct PersonViewModel { varname: String? var age: String? enum InputError: ErrorType { case InputMissing case AgeIncorrect } func createPerson() throws -> Person { guard let age = age, let name = name else { throw InputError.InputMissing } guard let ageFormatted = Int(age) else { throw InputError.AgeIncorrect } return Person(name: name, age: ageFormatted) } }
- 35. class ViewController: UIViewController,UITextFieldDelegate { var personViewModel = PersonViewModel() // ... truncated ... // @IBAction func onSubmitButtonTap(sender: AnyObject) { view.endEditing(true) do { let person = try personViewModel.createPerson() print("Success! Person created. (person)") } catch PersonViewModel.InputError.InputMissing { print("Input missing!") } catch PersonViewModel.InputError.AgeIncorrect { print("Age Incorrect!") } catch { print("Something went wrong, please try again!") } } }
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- 38. • Performance Tests •Asynchronous Tests • Xcode CI Improvements • UI Tests • Code Coverage
- 43. Still Learning… • ValueTypes • Optionals?! • Testing
- 44. To Learn… • do •guard • defer • error handling • protocol extensions • print • pattern matching • early exits • UI Testing • WatchOS • UIStackView • Security • Complications • Continuous Integration • App Thinning • Crash Logs • Objective-C Generics