1 

     2 import CW8a._

     3 

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

     5 

     6 assert(size(der('a', der('a', EVIL_urban))) == 28)

     7 assert(size(der('a', der('a', der('a', EVIL_urban)))) == 58)

     8 

     9 assert(size(ders("aaaaaa".toList, EVIL_urban)) == 8)

    10 assert(size(ders(("a" * 50).toList, EVIL_urban)) == 8)