How do we return an optional enum value from Swift to Obj-C? - objective-c

Question

We know how to expose Swift enums to Obj-C:
#objc enum Animal: Int {
case Cat, Dog
}
But the compiler complains that the following "cannot be represented in Obj-C":
func myAnimal() -> Animal? {
if hasPet() {
return .Cat
} else {
return nil
}
}
Ideas?

Answer 1

Optional Ints in Swift don't map to a type in Objective-C. The issue is that your myAnimal() method is returning a type that can't be represented in Objective-C.
The way I see it, you have two options...
Option1: Change your method's return type:
func myAnimal() -> NSNumber? {
// method body goes here.
}
This doesn't really seem great since in Objective-C you'd have to do something like this:
if (myAnimal().integerValue == AnimalCat) {
// do stuff here
}
Option 2: Add a catch-all case in your enum
#objc enum Animal: Int {
case none = 0
case cat = 1
case dog = 2
init(rawValue: Int) {
switch rawValue {
case 1: self = Cat
case 2: self = Dog
default: self = None
}
}
}
// Updated method signature that makes the compiler happy.
func myAnimal() -> Animal {
if hasPet() {
return .Cat
} else {
return .None
}
}
This way, you can change your method signature to not return an optional, and the compiler will be happy.