Functions passed to functions (delegates)

  def turnNumbersToEven() = {
    val nums = 1 to 20
    println( nums.map(a => addOneToNumberIf(a % 2 == 1)( a)) )
  }
  def addOneToNumberIf( test : => Boolean)( i : Int) : Int = {
    if (test) {
      return i + 1
    } else {
      return i
    }
  }

Note because we used addOneToNumberIf(a)(b) notation instead of addOneToNumberIf(a,b) notation we are allowed to write scripts {} like this:

  def turnNumbersToEven() = {
    val nums = 1 to 20
    println( nums.map(a => addOneToNumberIf {a % 2 == 1} (a)) )
  }