Typeclass Example

Main.scala

package wolfendale

case class Person(name: String)

object Typeclasses extends App {

  import Show.Showable

  val tuple = (Person("Michael"), Person("Not Michael"))
  val tuple2 = (Person("Michael"), (Person("Not Michael"), Person("Foo")))

  println(tuple.show)
}

Show.scala

package wolfendale

trait Show[A] {
  def show(a: A): String
}

object Show {

  implicit val personInstance: Show[Person] = new Show[Person] {
    override def show(a: Person): String = a.name
  }

  implicit def tupleInstances[A : Show, B : Show]: Show[(A, B)] = new Show[(A, B)] {
    override def show(a: (A, B)): String = s"(${a._1.show}, ${a._2.show})"
  }

  implicit class Showable[A : Show](a: A) {
    def show: String =
      implicitly[Show[A]].show(a)
  }
}