OptionalOr.swift

let nilString: String? = nil
let aString: String? = "a non-nil string"

print (nilString ?? "the string is nil")
print (aString ?? "the string is nil")

// if you don't want to use `??` …
// (inspired by Scala's Option's `getOrElse`)

extension Optional {
    func or(ifNil: Wrapped) -> Wrapped {
        switch self {
        case .None:
            return ifNil
        case let .Some(wrappedValue):
            return wrappedValue
        }
    }
}

print(nilString.or("the string is nil"))  // "the string is nil"
print(aString.or("the string is nil"))  // "a non-nil string"