ItemValidation.scala

class Settings extends Record {
  import Dsl._

  val maxQty = req("maxQty", 1, IntTransformer).ensuring{v=> v >=! 0}
  //Alternate version
  val maxQty = req("maxQty", 1, IntTransformer).ensuring(>=!0).ensuring(!==!666)
  val minQty = opt(req("minQty", 2, IntTransformer).ensuring(>=!0))

  override def check : Option[ErrorMsg] = {
    maxQty.value >=! minQty.value
  }
}