Swift Functional Programming - Second Edition

Mixing value and reference types

In real-world problems, we may need to mix reference types with value types. For instance, we may need to have a reference to class in struct like our previous example or we may need to have a struct variable in class. How would we reason about the assignments and copying in these circumstances?

Let's examine the following example:

class User {     var name: String     init(name: String) {         self.name = name     } } let julie = User(name: "Julie") struct Student {     var user: User } let student = Student(user: julie) student.user.name // prints "Julie" let anotherStudent = student julie.name = "Julie Jr." anotherStudent.user.name // prints "Julie Jr."

In this example, we have a User class and a Student struct that ...