Cocoa Programming for OS X: The Big Nerd Ranch Guide

Enumerations and the Switch Statement

An enumeration (“enum” for short) is a type with a discrete set of values. Define an enum describing pies:

e​n​u​m​ ​P​i​e​T​y​p​e​ ​{​
 ​ ​ ​ ​c​a​s​e​ ​A​p​p​l​e​
 ​ ​ ​ ​c​a​s​e​ ​C​h​e​r​r​y​
 ​ ​ ​ ​c​a​s​e​ ​P​e​c​a​n​
}​

l​e​t​ ​f​a​v​o​r​i​t​e​P​i​e​ ​=​ ​P​i​e​T​y​p​e​.​A​p​p​l​e​

When the compiler expects the enum type, you can skip the full type name. For example:

v​a​r​ ​p​i​e​s​T​o​B​a​k​e​:​ ​[​P​i​e​T​y​p​e​]​ ​=​ ​[​]​
p​i​e​s​T​o​B​a​k​e​.​a​p​p​e​n​d​(​.​A​p​p​l​e​)​

Swift has a powerful switch statement which, among other things, is great for matching on enum values:

l​e​t​ ​n​a​m​e​:​ ​S​t​r​i​n​g​
s​w​i​t​c​h​ ​f​a​v​o​r​i​t​e​P​i​e​ ​{​
c​a​s​e​ ​.​A​p​p​l​e​: