PatternMatch.swift

struct BeginsWith {
    let value: String
    init(_ value: String) {
        self.value = value
    }
}

func ~=(pattern: BeginsWith, value: String) -> Bool {
    return value.hasPrefix(pattern.value)
}

let s = "Hello world"

switch s {
case BeginsWith("Hello"):
    print("got it \(s)")
case BeginsWith("Goodbye"):
    print("didn't get it \(s)")
default:
    break
}

////////////////////////////////////////////////////

func ~=(pattern: String, value: Int) -> Bool {
    return pattern == String(describing: value)
}

let x = (1,2,3)

switch x {
case ("10", "2", _):
    print("Got it")
default:
    print("Didn't get it")
}