Uncommon ways to handle optionals in Swift

optionals.swift

var dic = [String: Int]()
dic["hello", default: 0] += 1
dic // ["hello": 1]

func parse(_ string: String) -> String {
    switch Int(string) {
    case .some(7): return "SEVEN"
    case 5?: return "FIVE"
    case let x? where x < 10: return "1-9"
    default: return "Not valid INT"
    }
}

parse("7") // "SEVEN"
parse("c") // Not valid
parse("5") // "FIVE"
parse("8") // "1-9"

var arr = [1, 7, 10, nil, 6, nil, 20]

for case let x? in arr { // only loop for non nil integers
    print(x)
}
// 1, 7, 10, 6, 20