Run Length encoding in Scala

RunLengthEncoding.scala

object RunLengthEncoding extends App {
	
	val data = List("a","a", "a", "b","b", "a", "c", "c", "c")
	
	def pack[T](vals: List[T]): List[List[T]] = vals match {
		case Nil => Nil
		case x :: xs1 => 
		  val (first, rest) = vals span (y => y == x)
		  first :: pack(rest)
	}
	
	def encode[T](vals: List[T]): List[(T, Int)] =
	  pack(vals) map (ys => (ys.head, ys.length))
	  

	println(encode(data))
   
	
	
  
}