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

let point = (0, 0)
switch point {
case ("0", "0"):
    print("(0, 0) is at the origin.")
default:
    print("The point is at (\(point.0), \(point.1)).")
}

enum Pattern {
    case zero
}

func ~=(pattern: Pattern, value: Int) -> Bool {
    return value == 0 && pattern == .zero
}

switch point {
case (Pattern.zero, Pattern.zero):
    print("(0, 0) is at the origin.")
default:
    print("The point is at (\(point.0), \(point.1)).")
}

error: CustomPatternMatchEnum.playground:20:15: error: enum case 'zero' is not a member of type 'Int'
case (Pattern.zero, Pattern.zero):
              ^

error: CustomPatternMatchEnum.playground:20:29: error: enum case 'zero' is not a member of type '<<error type>>'
case (Pattern.zero, Pattern.zero):
                            ^

struct Pattern {
    let sentinel: Int
    static let zero = Pattern(sentinel: 0)
}

extension Pattern: Equatable {
    static func ==(lhs: Pattern, rhs: Pattern) -> Bool {
        return lhs.sentinel == rhs.sentinel
    }
}

func ~=(pattern: Pattern, value: Int) -> Bool {
    return value == 0 && pattern == .zero
}

switch point {
case (Pattern.zero, Pattern.zero):
    print("(0, 0) is at the origin.")
default:
    print("The point is at (\(point.0), \(point.1)).")
}