Recursive Struct through Indirect Enum

Recursive Struct.swift

struct Path: CustomStringConvertible {

    private var hasParent = HasParent.No

    var key: String


    init(forKey key: String, inParent parent: Path? = nil) {
        self.key = key
        self.parent = parent
    }


    var description: String {
        if let parent = parent {
            return "\(parent).\(key)"
        }
        else {
            return key
        }
    }


    var parent: Path? {
        get {
            switch hasParent {
            case .No:              return nil
            case let .Yes(parent): return parent
            }
        }
        set {
            if let parent = newValue {
                hasParent = .Yes(parent)
            }
            else {
                hasParent = .No
            }
        }
    }



    private enum HasParent {
        case No
        indirect case Yes(Path)
    }
}


let level0 = Path(forKey: "level0")
let level1 = Path(forKey: "level1", inParent: level0)
let level2 = Path(forKey: "level2", inParent: level1)
let level3 = Path(forKey: "level3", inParent: level2)

print(level3)
// output: level0.level1.level2.level3