1 

     2 import scala.concurrent._

     3 import scala.concurrent.duration._

     4 import ExecutionContext.Implicits.global

     5 import scala.language.postfixOps 

     6 

     7 

     8 

     9 lazy val f = Future {

    10   assert(der('a', ZERO | ONE) == (ZERO | ZERO))

    11   assert(der('a', (CHAR('a') | ONE) ~ CHAR('a')) == ALT((ONE | ZERO) ~ CHAR('a'), ONE))

    12   assert(der('a', STAR(CHAR('a'))) == (ONE ~ STAR(CHAR('a'))))

    13   assert(der('b', STAR(CHAR('a'))) == (ZERO ~ STAR(CHAR('a'))))

    14 }

    15 

    16 Await.result(f, 120 second)