Functional Scala ... tail recursive computation of fib number

fib.scala

 //tail recursive fibonacci numbers
  def fib(n: Int) = {
  	@scala.annotation.tailrec
  	def fibImpl(a:Int, nxt: Int, res: Int) : Int =
  		a match {
  			case 0 => res
  			case _ => fibImpl(a-1, nxt+res, nxt)
  		}
  	fibImpl(n, 1, 0);
  }
  
  (0 until 10) map fib