How are optional values implemented in Swift?

Question

I wonder how the value types in Swift (Int, Float...) are implemented to support optional binding (\"?\"). I assume those value types are not allocated on the heap, but on t

Answer 1

Optionals are implemented as shown below. To find this, CMD-Click on a declaration like var x: Optional. var x: Int? is just syntactic sugar for that.

enum Optional : LogicValue, Reflectable {
    case None
    case Some(T)
    init()
    init(_ some: T)

    /// Allow use in a Boolean context.
    func getLogicValue() -> Bool

    /// Haskell's fmap, which was mis-named
    func map(f: (T) -> U) -> U?
    func getMirror() -> Mirror
}