Simpler implementation

MaskType.swift

//  IBEnum.swift


import Foundation


public protocol IBEnum  {
  init?(string:String)
}

public extension IBEnum {
  
  
  /// Helper function that returns a tuple containing the name and params
  ///
  ///
  /// - Discussion
  /// Since "name(param1,param2,param3)" is the classic IBAnimatable format
  ///
  /// this method will return "wave"
  static func extractNameAndParams(_ string:String) -> (name:String, params:[String]) {
    let tokens = string.components(separatedBy: CharacterSet(charactersIn: "()")).filter({!$0.isEmpty}) // extract params list   self.enumName
    let maskName = tokens.first ?? "";
    let paramsString = tokens.count >= 2 ? tokens[1] : "";
    let params = paramsString.components(separatedBy: ","); // params list
    return (name:maskName, params:params);
  }
  
}


import Foundation
import UIKit

public enum MaskType: IBEnum {
  case circle
  case polygon(sides:Int?)
  case star(points:Int?)
  case triangle
  case wave(direction:WaveDirection?, width:Float?, offset:Float?)
  case parallelogram(angle:Double?)
  case none
  
  public enum WaveDirection:String {
    case up
    case down
  }
}

// ---------------------------- MASKType ---------------------------------------------------

public extension MaskType  {
  init(string:String) {
    let paramsAndName = MaskType.extractNameAndParams(string)
    let name = paramsAndName.name;
    let params = paramsAndName.params;
    
    switch name.lowercased() {
    case "circle":
      self = MaskType.circle
    case "polygon":
      self = MaskType.polygon(sides: nil)
    case "star":
      self = MaskType.star(points: Int(params[0]))
    case "triangle":
      self = MaskType.triangle;
    case "wave":
      self = MaskType.wave(direction: WaveDirection(rawValue:params[0].lowercased()), width: Float(params[1]), offset:Float(params[2]))
    case "parallelogram":
      self = MaskType.parallelogram(angle: Double(params[0]))
    default:
      self = MaskType.none
    }
  }
}

I like this version. +1 I think it is OK to have a custom init for every enum, and they can use extension method extractNameAndParams to cover String into enum.