Swift Programming: The Big Nerd Ranch Guide

Using Value and Reference Types Together

This chapter may have made you wonder, “Can I put a value type inside of a reference type? Can I put a reference type inside of a value type?” The answer to both of these questions is “Yes,” and you did the latter by adding a property of the class GreekGod to Pantheon. But you must be very careful about using a reference type inside of a value type. Consider the following example that changes the name of hecate.

Listing 18.12  The Romans are coming

...
struct Pantheon {
    var chiefGod: GreekGod
}

let pantheon = Pantheon(chiefGod: hecate)
let zeus = GreekGod(name: "Zeus")
zeus.name = "Zeus Jr."
zeus.name

pantheon.chiefGod.name // "AnotherHecate"
let greekPantheon = pantheon
hecate.name = "Trivia" ...