Swift Language Enums Initializers
Example
Enums can have custom init methods that can be more useful than the default init?(rawValue:). Enums can also store values as well. This can be useful for storing the values they where initialized with and retrieving that value later.
enum CompassDirection {
case north(Int)
case south(Int)
case east(Int)
case west(Int)
init?(degrees: Int) {
switch degrees {
case 0...45:
self = .north(degrees)
case 46...135:
self = .east(degrees)
case 136...225:
self = .south(degrees)
case 226...315:
self = .west(degrees)
case 316...360:
self = .north(degrees)
default:
return nil
}
}
var value: Int = {
switch self {
case north(let degrees):
return degrees
case south(let degrees):
return degrees
case east(let degrees):
return degrees
case west(let degrees):
return degrees
}
}
}
Using that initializer we can do this:
var direction = CompassDirection(degrees: 0) // Returns CompassDirection.north
direction = CompassDirection(degrees: 90) // Returns CompassDirection.east
print(direction.value) //prints 90
direction = CompassDirection(degrees: 500) // Returns nil
