gistfile1.scala

import scala.xml.{Elem, NodeSeq}

object Match {
val input =
<square>
  <double><val>3</val></double>
</square>

//def proc(input:NodeSeq):Function1[Int, Int] = input match {
def proc(input:NodeSeq):Int = input match {
  case <square>{children @ _ *}</square> => {println("square"); 4*  proc(children.filter(_.isInstanceOf[Elem])(0)) }
  case <double>{children @ _ *}</double> =>  {println("double"); 2 * proc(children.filter(_.isInstanceOf[Elem])(0)) }
  case x => x.text.toInt 
}

}