…proper implementation of a string type in Swift has been a controversial topic for quite some time. The design is a delicate balance between Unicode correctness, encoding agnosticism, ease-of-use and high-performance. Almost every major release of Swift has refined the String type to the awesome design…

…different formats using various encoders and decoders. JSON data Plist data Custom data JSONEncoder PropertyListEncoder PropertyListDecoder Custom encoders Custom decoders PERSON id: UUID name: String address: struct favorite: enum Conforms to Codable JSONDecoder What you’ll learn, and what you won’t Because this is an advanced book…

…text printer. Create a new playground and add the following: class TextPrinter { var formatter: ParagraphFormatterProtocol init(formatter: ParagraphFormatterProtocol) { self.formatter = formatter } func printText(_ paragraphs: [String]) { for text in paragraphs { let formattedText = formatter.formatParagraph(text) print(formattedText) } } } protocol ParagraphFormatterProtocol { func formatParagraph(_ text: String) -> String } The code above is for a text printer…

…base: Encrypted } Then, imagine you have a Person struct with a private property called password: struct Person { let id: UUID let name: String private let password: String } If you extend Encrypter in the same file to provide encryption for Person, like so: extension Encrypter where Encrypted == Person { func encrypt…

…your protocols: struct Text: ImmutableLocalizable { static let supportedLanguages: [Language] = [.english, .croatian] var content = "Help" func changed(to language: Language) -> Self { let newContent: String switch language { case .english: newContent = "Help" case .german: newContent = "Hilfe" case .croatian: newContent = "Pomoć" } return Text(content: newContent) } } The Text struct implements the ImmutableLocalizable protocol. This…

…replace the contents of fetchArticles with the following: let baseURL = "https://api.kodeco.com/api" let path = "/contents?filter[content_types][]=article" let url = URL(string: baseURL + path)! do { // 1 let articlesData = try await networker.fetch(url: url) // 2 let decoder = JSONDecoder() let decodedArticles = try decoder .decode(Articles.self, from: articlesData).data articles = decodedArticles.map…

…looks like: May consume elements Sequence Access by index Collection Iteration state IteratorProtocol Change elements MutableCollection Forward, backward traversal BidirectionalCollection Change subranges RangeReplaceableCollection Unify String and Substring StringProtocol Random access traversal RandomAccessCollection vends Sequence types protocol hierarchy The hierarchy includes: Sequence - This is the most primitive type in the hierarchy…

…infoWriter = InformationWriter(writer: self) infoWriter?.doSomething() } Moreover, MemoryLeaksViewController conforms to the protocol WriterProtocol, which only defines the method writeText(_:): protocol WriterProtocol { func writeText(_ text: String) } Now, look at InformationWriter.swift. Its init takes a writer as the parameter and creates a closure that calls writeText(_:) on that writer: init(writer: WriterProtocol…

…particular situation. As discussed in the previous chapter, it’s pretty incredible that all the standard library types such as Bool, Int, Double, String, Optional, Array and Dictionary are clever compositions of these fundamental types. It speaks to the power of what you can do with them. Note: Protocols…

…functionality and codifies their two’s complement representation, which you’ll learn about shortly. But there’s more. Integers losslessly convert to and from String types thanks to additional protocols and methods. The protocol relationships look like this: min, max, endian, wrapping, random, ... FixedWidthInteger bitWidth, bitwise, %, ... BinaryInteger init? LosslessStringConvertible description…

…generics, which support a relatively large set of generic scenarios, such as bridging Array<FeedItem> to NSArray <FeedItem *>*, Dictionary<String, Any> to NSDictionary<NSString*, id>* and vice versa. It will even keep generic constraints of your own Objective-C classes…

…being multi-paradigm. Apple demonstrated Swift’s modern language features at that first conference (WWDC14). In the first live demo, they functionally mapped strings to SpriteKit images. In addition to handling the intricacies of giant, legacy object-oriented frameworks, such as UIKit, CoreData and SpriteKit, Swift can also speak functionally…

…failure, and a completion event indicates a valid and expected completion of the stream. Infinite float stream, never completes Boolean stream, ends with completion String stream, ends with failure 0 8.2 42 83 false false true false eel act ace rag Thinking of water Streams of data are analogous…

This means you cannot access uninitialized memory and can only treat an instance as the type it was created. You can’t treat a String as if it were an Int or a Numeric and vice-versa. But this doesn’t cover completely what the word safe means…

…intimately familiar with protocols and generics. Section II: Standard Library This section covers the base layer of writing Swift programs: Numerics, Ranges, Strings, Sequences, Collections, Codable and the less obvious, but very important topic - Unsafe. As you’d expect from an advanced book, we don’t only explain these topics…