simple occurrence combo

gistfile1.scala

def combinations(occurrences: Occurrences): List[Occurrences] = {
  def combo(l: Occurrences): List[Occurrences] = {
    l match {
      case Nil => List()
      case occurrence :: tail => {
      	val rest = combo(tail)
        val occurrenceList = (1 to occurrence._2).map( num => List( (occurrence._1,num) )).toList
        occurrenceList ::: occurrenceList.flatMap(x => rest.map(y => x ::: y).toList).toList ::: rest
      }
    }
  }
  List()::combo(occurrences)
}