54   case n => SEQ(r, NTIMES(r, n - 1))

    54   case n => SEQ(r, NTIMES(r, n - 1))

    55 }

    55 }

    56 

    56 

    57 // the evil regular expression  a?{n} a{n}

    57 // the evil regular expression  a?{n} a{n}

    58 def EVIL1(n: Int) = SEQ(NTIMES(OPT(CHAR('a')), n), NTIMES(CHAR('a'), n))

    58 def EVIL1(n: Int) = SEQ(NTIMES(OPT(CHAR('a')), n), NTIMES(CHAR('a'), n))

    59 val EVIL2 = SEQ(STAR(CHAR('a')), CHAR('b'))

    61 val EVIL2 = SEQ(STAR(CHAR('a')), CHAR('b'))

    60 

    62 

    61 //for measuring time

    63 //for measuring time

    62 def time_needed[T](i: Int, code: => T) = {

    64 def time_needed[T](i: Int, code: => T) = {

    63   val start = System.nanoTime()

    65   val start = System.nanoTime()