gistfile1.scala

trait Read[T] {
  def read(st: String): T
}

implicit object IntRead extends Read[Int] {
  def read(s: String) = s.toInt
}

implicit object StringRead extends Read[String] {
  def read(s: String) = s
}

// for generic list
implicit def ListRead[A](implicit r: Read[A]) =
  new Read[List[A]] {
    def read(s: String) = {
      val es = s.split(" ").toList
      es.map(r.read(_))
    }
  }

// for list of strings : read converts to upper case also
implicit def ListStringRead(implicit r: Read[String]) =
  new Read[List[String]] {
    def read(s: String) = {
      val es = s.split(" ").toList
      es.map(r.read(_).toUpperCase)
    }
  }

def foo[T : Read](s: String) = implicitly[Read[T]].read(s)

foo[List[Int]]("1 2 3 4") // List(1, 2, 3, 4)
foo[List[String]]("a b c d") // List("A", "B", "C", "D")