Swift enum both a string and an int

Question

I have a situation where I'm trying to do binary decoding of some data and the data types have both a numerical value and a string value and a name. I was thinking of using an enum such as:

enum TARGET_TRACK_TYPE : String {     case TT_INVALID          = "Invalid"     case TT_TRUE_TRACK_ANGLE = "True Track Angle"     case TT_MAGNETIC         = "Magnetic"     case TT_TRUE             = "True" } 

However I also know that:

TT_INVALID = 0 and TT_TRUE_TRACK_ANGLE = 1, etc. Is there an easy way to encapsulate both these "things" the string and the numerical value into an enum construct or do i need to make some sort of struct/class to handle this?

I guess I'd like to do something like

let a = TARGET_TRACK_TYPE.rawValue(value: 2) println(a)

which would print True Track Angle

Again, I know this can be done with a struct or a class but I'm specifically interested in the enum

Or for another example:

/// Emitter Category is defined in section 3.5.1.10 of the GDL90 Spec struct EmitterCategory {  let category : Int  func getString() -> String {      switch(category) {     case 0:         return "No aircraft type information";     case 1:         return "Light";     case 2:         return "Smalle";     case 3:         return "Large";     case 4:         return "High Vortex Large";     case 5:         return "Heavy";     case 6:         return "Highly Manuverable";     case 7:         return "Rotorcraft";     case 8:         return "(Unassigned)";     case 9:         return "Glider/sailplane";     case 10:         return "Ligther than air";     case 11:         return "Parachutist/sky diver";     case 12:         return "Ultra light/hang glider/paraglider";     case 13:         return "(Unassigned)";     case 14:         return "Unmanned aerial vehicle";     case 15:         return "Space/transatmospheric vehicle";     case 16:         return "(Unassigned)";     case 17:         return "Surface vehicle - emergency vehicle";     case 18:         return "Surface vehicle - service vehicle";     case 19:         return "Point obstacle";     case 20:         return "Cluster Obstacle";     case 21:         return "Line Obstacle";     default:         return "(reserved)";     } } } 

Is there a way to refactor this struct into an enum such that I construct the enum with an integer value but I "read" the enum as a string? I'm pretty sure the answer is no.

Answer 1

I think this will do it for me. Thank you self.. :)

protocol GDL90_Enum  {       var description: String { get } }  enum TARGET_ADDRESS_TYPE : Int, GDL90_Enum {    case ADSB_ICAO_ADDRESS = 0    case ADSB_SELF_ADDRESS = 1    case TISB_ICAO = 2    case TISB_TRACK_ID = 3    case SURFACE_VEHICLE = 4    case GROUND_STATION = 5     var description: String {       switch self {    case .ADSB_ICAO_ADDRESS:       return "ADS-B with ICAO address"    case .ADSB_SELF_ADDRESS:       return "ADS-B with Self-assigned address"    case .TISB_ICAO:       return "TIS-B with ICAO address"    case .TISB_TRACK_ID:          return "TIS-B with track file ID"    case .SURFACE_VEHICLE:          return "Surface Vehicle"    case .GROUND_STATION:          return "Ground Station Beacon"    default:          return "Reserved"       }    } } 

Answer 2

With Swift 4.2 this can be done using CaseIterable. One, relatively concise way is to do the following

enum Directions: String, CaseIterable {     case north, south, east, west      static var asArray: [Directions] {return self.allCases}      func asInt() -> Int {         return Directions.asArray.firstIndex(of: self)!     } }  print(Directions.asArray[2]) // prints "east\n"  print(Directions.east.asInt()) // prints "2\n"  print(Directions.east.rawValue) // prints "east\n"