Enumeration with raw values

Question

Why I can't define enumeration with raw values like this?

enum Edges : (Double, Double) {
    case TopLeft = (0.0, 0.0)
    case TopRight = (1.0, 0.0)
    case BottomLeft = (0.0, 1.0)
    case BottomRight = (1.0, 1.0)
}

Answer 1

Because:

Raw values can be strings, characters, or any of the integer or floating-point number types.

But there is an alternative solution for you:

enum Edges {
    case TopLeft
    case TopRight
    case BottomLeft
    case BottomRight

    func getTuple() -> (Double, Double) {
        switch self {
        case .TopLeft:
            return (0.0, 0.0)
        case .TopRight:
            return (1.0, 0.0)
        case .BottomLeft:
            return (0.0, 1.0)
        case .BottomRight:
            return (1.0, 1.0)
        }
    }
}

let a = Edges.BottomLeft
a.getTuple() // returning (0, 1)