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> def date(month:Int=10, day:Int) = "%s/%s" format (month, day) date: (month: Int,day: Int)String scala> date(30) <console>:7: error: not enough arguments for method date: (month: Int,day: Int)String.
scala> def log(msg:String, length:Int = msg.length) = "[%s] %s" format(length, msg) <console>:5: error: not found: value msg def log(msg:String, length:Int = msg.length) = "[%s] %s" format(length, msg) ^