enumFrom

enumFrom.swift

protocol StringDecodable {
  init?(string: String)
}

extension Dictionary where Key: JSONKey, Value: AnyObject {
  /// Converts a string to an enum value
  func enumFrom<T: StringDecodable>(key: Key, _ enumType: T.Type) -> T? {
    if let s = self[key] as? String {
        return enumType.init(string: s)
    }
    return nil
  }
}

private enum TestEnum: StringDecodable {
  case Foo
  init(string: String) { self = .Foo }
}

let d = ["foo": "bar"]
let result = d.enumFrom("foo", TestEnum.self)
// (!) Cannot invoke 'enumFrom' with an argument list of type '(String, TestEnum.Type)'