1 

     2 import CW8a._

     3 

     4 val EVIL_urban = SEQ(STAR(STAR(CHAR('a'))), CHAR('b'))

     5 

     6 assert(ders(("a" * 5).toList, EVIL_urban) == SEQ(SEQ(STAR(CHAR('a')),STAR(STAR(CHAR('a')))),CHAR('b')))

     7 assert(ders(List('b'), EVIL_urban) == ONE)

     8 assert(ders(List('b','b'), EVIL_urban) == ZERO)

     9 assert(matcher(EVIL_urban, "a" * 5 ++ "b") == true)

    10 assert(matcher(EVIL_urban, "a" * 500 ++ "b") == true)

    11 assert(matcher(EVIL_urban, "a" * 500) == false)

    12 assert(matcher(EVIL_urban, "b") == true)

    13 assert(matcher(EVIL_urban, "bb") == false)

    14 assert(matcher("abc", "abc") == true)

    15 assert(matcher(("ab" | "a") ~ (ONE | "bc"), "abc") == true)

    16 assert(matcher(ONE, "") == true)

    17 assert(matcher(ZERO, "") == false)

    18 assert(matcher(ONE | CHAR('a'), "") == true)

    19 assert(matcher(ONE | CHAR('a'), "a") == true)