import scala.concurrent._
import scala.concurrent.duration._
import ExecutionContext.Implicits.global
import scala.language.postfixOps 



lazy val f = Future {
  assert(nullable(ZERO) == false)
  assert(nullable(ONE) == true)
  assert(nullable(CHAR('a')) == false)
  assert(nullable(ZERO | ONE) == true)
  assert(nullable(ZERO | CHAR('a')) == false)
  assert(nullable(ONE ~  ONE) == true)
  assert(nullable(ONE ~ CHAR('a')) == false)
  assert(nullable(STAR(ZERO)) == true)
}

Await.result(f, 120 second)