Response to http://stackoverflow.com/questions/24459171/swift-switch-statement-on-a-tuple-of-optional-booleans

gistfile1.txt

var dict = Dictionary<String,Bool>()
dict["a"] = true

dict["c"] = false

func matchOneOrTheOtherWithOptionals(a: Bool?, b: Bool?) -> String {
    switch (a, b) {
    case (.Some(true), let b) where b == .None || !b!:
        return "a was true, but b was None or false"
    case (let a, .Some(true)) where a == .None || a == .Some(false):
        return "a was None or false and b was true"
    default:
        return "They both had a value, or they were both missing a value"
    }
}

matchOneOrTheOtherWithOptionals(true, .None)
matchOneOrTheOtherWithOptionals(true, false)
matchOneOrTheOtherWithOptionals(.None, true)
matchOneOrTheOtherWithOptionals(false, true)

matchOneOrTheOtherWithOptionals(false, false)
matchOneOrTheOtherWithOptionals(true, true)
matchOneOrTheOtherWithOptionals(.None, .None)

func noneToFalse(bool: Bool?) -> Bool {
    if let b = bool {
        return b
    } else {
        return false
    }
}

func matchOneOrTheOther(a: Bool, b: Bool) -> String {
    switch (a, b) {
    case (true, false):
        return "a is true, b was false or None"
    case (false, true):
        return "a was false/None, b was true"
    default:
        return "both were true, or both were false/None"
    }
}

matchOneOrTheOther(noneToFalse(dict["a"]), noneToFalse(dict["b"]))