Scala 3 में Enums

enum Color:
  case Red, Green, Blue

object Main:
  def main(args: Array[String]): Unit =
    println(Color.Red)

enum Color:
  case Red, Green, Blue

object Main:
  def main(args: Array[String]): Unit =
    Color.values.foreach(println)
    println(Color.valueOf("Green"))

enum Color:
  case Red, Green, Blue

object Main:
  def main(args: Array[String]): Unit =
    println(Color.Blue.ordinal)
    println(Color.Red.ordinal)

enum Planet(val mass: Double):
  case Earth extends Planet(5.97e24)
  case Mars  extends Planet(6.42e23)

object Main:
  def main(args: Array[String]): Unit =
    println(Planet.Earth.mass)
    println(Planet.Mars.mass)

enum Direction:
  case North, South, East, West
  def opposite: Direction = this match
    case North => South
    case South => North
    case East  => West
    case West  => East

object Main:
  def main(args: Array[String]): Unit =
    println(Direction.North.opposite)

enum Maybe[+A]:
  case Just(value: A)
  case Nothing

object Main:
  def main(args: Array[String]): Unit =
    val a: Maybe[Int] = Maybe.Just(42)
    println(a)

enum Tree[+A]:
  case Leaf(value: A)
  case Branch(left: Tree[A], right: Tree[A])

object Main:
  def main(args: Array[String]): Unit =
    val t = Tree.Branch(Tree.Leaf(1), Tree.Leaf(2))
    println(t)

enum Light:
  case Red, Yellow, Green

object Main:
  def action(l: Light): String = l match
    case Light.Red    => "stop"
    case Light.Yellow => "slow"
    case Light.Green  => "go"

  def main(args: Array[String]): Unit =
    println(action(Light.Green))

enum Suit:
  case Hearts, Diamonds, Clubs, Spades

object Main:
  def main(args: Array[String]): Unit =
    println(Suit.values.length)
    println(Suit.Spades.ordinal)

enum Currency(val symbol: String):
  case USD extends Currency("$")
  case EUR extends Currency("\u20ac")
  def format(amount: Double): String = s"$symbol$amount"

object Main:
  def main(args: Array[String]): Unit =
    println(Currency.USD.format(9.99))

enum Result[+E, +A]:
  case Ok(value: A)
  case Err(error: E)

object Main:
  def main(args: Array[String]): Unit =
    val r: Result[String, Int] = Result.Ok(7)
    println(r)

enum Weekday:
  case Mon, Tue, Wed, Thu, Fri
  def isStart: Boolean = this == Mon

object Main:
  def main(args: Array[String]): Unit =
    println(Weekday.Mon.isStart)
    println(Weekday.values.length)