CaseMatchExample.scala

sealed abstract class Gender
case object Male extends Gender
case object Female extends Gender

case class Person(name: String, age: Int, gender: Gender)

object CaseMatchExample extends App {
  val people = List(
    Person("yuu", 25, Male),
    Person("mizuki", 27, Female),
    Person("satoshi", 51, Male))
  
  people foreach { person =>
    person match {
      case Person(name, _, Female)             => println(s"$name is female")
      case Person(name, age, Male) if age < 30 => println(s"$name is a young man")
      case Person(name, _, _)                  => println(s"$name is a gentleman")
    }
  }
  // The outputs
  //   yuu is a young man
  //   mizuki is female
  //   satoshi is a gentleman
  
  // you can write more shortly like this
  /*
  people foreach {
    case Person(...
    case Person(...
    case Person(...
  }
  */
  
  val foundPerson: Option[Person] = people.find(_.name == "yuki")
  foundPerson match {
    case None => println("can't find a person who has name yuki")
    case Some(person) => println(s"yuki found! And his age is ${person.age}")
  }
  
  // you can write more shortly like this
  /*
  people.find(_.name == "yuki") match {
    case None ...
    case Some(...
  }
  */
}