Structs Part II

// STRUCTS - PART II
// Structs come with their own memberwise initializer
// but we can provide our own init() method
// to initialize all stored properties
struct User {
    var username: String

    init() {
        username = "Anonymous"
        print("We have a new user!")
    }
}

var person = User()
person.username             // "Anonymous"
person.username = "leck"
print(person.username)      // "leck"

// SELF: REFERRING TO THE CURRENT INSTANCE
// Useful when a property and init parameter share the same name
struct Car {
    var color: String

    init(color: String) {
        self.color = color
    }
}

let buick = Car(color: "red")
print(buick.color)              // "red"

// LAZY PROPERTIES
// Property is only created when it is first accessed
struct FamilyTree {
    init() {
        print("Creating family tree")
    }
}

struct Person {
    var name: String
    lazy var familyTree = FamilyTree()  // property not created unless accessed

    init(name: String) {
        self.name = name
    }
}

var ed = Person(name: "ed")
// Access familyTree property to see message:
ed.familyTree       // "Creating family tree"

// ACCESS CONTROL
// Use "private" to restict access to properties and functions
// within a given struct
// Struct's memberwise contructor not available with private properties
struct PrivateData {
    var name: String
    private var idNumber: Int

    init(name: String, idNumber: Int) {
        self.name = name
        self.idNumber = idNumber
    }

    func printTheId() {
        print("The id is \(idNumber)")
    }

    private func privateMessage() {
        print("The id is \(idNumber)")
    }
}

let john = PrivateData(name: "John", idNumber: 9384092)
john.name                        // "John"
// john.idNumber                 // Not accessible
john.printTheId()                // "The id is 9384092"
// john.privateMessage()         // Not accessible

// STATIC PROPERTIES AND METHODS
struct StaticExample {
    var name: String
    static var quote = "It's not who you are underneath, but what you do that defines you."

    init(name: String) {
        self.name = name
    }
}

let bruceWayne = StaticExample(name: "Batman")
bruceWayne.name                     // "Batman"
StaticExample.quote                 // "It's not who..."