Swift "Enum" base object - swift

Question

If I want to add an extension to every object I can do the following:
extension AnyObject
{
func myFunc() { ... }
}
Is there something similar where I can add a function to every Enum? In other words, what is the base "class" for every enum?

Answer 1

First of all, note that you cannot do an extension to AnyObject as above, as AnyObject is a protected protocol (to which all classes implicitly conform) rather than a type. See e.g.
Is there a way to add an extension to AnyObject?
Now, you could, however, extend any specific type as you show above, e.g., extension Int { ... }. However enum is not a type; rather a "container" of ordered raw representable values. So a more valid comparison could be "If I want to add an extension to every class, by extension class ...", which is, naturally, trickier.
Now, all enumerations with a rawValue and an initializer by rawValue conforms to protocol RawRepresentable, so you could extend this protocol for specific types of raw values:
extension RawRepresentable where RawValue == Int {
var sqrt: Double {
return pow(Double(rawValue),(1/2))
}
}
And this extension property would be available to all enumerations that explicitly use the same raw value type, in this case, Int:
enum MyIntegerLiteralEnum : Int {
case One = 1
case Two
case Three
case Four
}
print(MyIntegerLiteralEnum.One.sqrt)
print(MyIntegerLiteralEnum.Two.sqrt)
print(MyIntegerLiteralEnum.Four.sqrt)
/* 1.0
1.4142135623731
2.0 */
As a disclaimer, note that this extension will be made available to all types that conforms to RawRepresentable with a rawValue of type Int, not only enum types. E.g.:
struct Foo : RawRepresentable {
typealias RawValue = Int
var bar : Int
var rawValue: RawValue {
get {
return bar
}
}
init(rawValue bar: Int) {
self.bar = bar
}
}
var a = Foo(rawValue: 16)
print(a.sqrt) // 4.0