名前つき引数による呼び出し | Codetter（こーどったー）

scala>  def date(year:Int, month:Int, day:Int) = "%s/%02d/%02d" format(year, month, day)
date: (year: Int,month: Int,day: Int)String

scala> date(2011, 07, 18)                                                               
res22: String = 2011/07/18

scala> date(day=19, year=2011, month=07)
res23: String = 2011/07/19