object foo {  
   class Z;
  case class X( x:List[Z] ) extends Z;
  case class Y( s:String ) extends Z;

  // this does not work
  def lookupByName( pb:X, Name:String ):Option[String] = pb match {
    case X(List( _ *, 
                X( List( 
                  Y( Name ),
                  Y( variable ) 
                   ))
         )) =>
      Some( variable )
  }

/* // this works
  def lookupByName( pb:X, Name:String ):Option[String] = pb match {
    case X(List( _ *, 
                  Y( Name ),
                  Y( variable ) 
         )) =>
      Some( variable )
  }
*/

}