SWIFT

swift ui enum

enum WeatherType {
    case sun
    case cloud
    case rain
    case wind
    case snow
}

func getHaterStatus(weather: WeatherType) -> String? {
    if weather == .sun {
        return nil
    } else {
        return "Hate"
    }
}

getHaterStatus(weather: .cloud)

define enum swift

Struct : Value Type | No Inheritance | No Deinitializers | No Type casting
Class : Reference Type | Inheritance supported | Has Deinitializers | Type casting

Common factors between struct and class:
Both allows to define properties to store values
Both allows to define methods
Both allows to define subscripts 
Both allows to define initializers
Both allows extension and protocols 

Enum in swift

// MARK: Enumerations used in swift

let result = "failure"
let result2 = "failed"
let result3 = "fail"
enum Result {
    case success
    case failure
}
let res = Result.failure
print(res)

swift enum nib

// There is no way to do this. But there is a little workaround.

// Swift 5:
public enum Size: String {
  case small = "small"
  case medium = "medium"
  case large = "large"
}

class SizeView: UIView {
  private var size: Size = .large

  @IBInspectable 
  public var sizeName: String = "large" {
    didSet {
      guard self.sizeName != oldValue else { return }
      self.size = Size(rawValue: self.sizeName)
    }
  }
}

Swift enum

enum Season {
  case spring, summer, autumn, winter
}