72 def OPT(r: Rexp) = ALT(r, ONE)  | 
    72 def OPT(r: Rexp) = ALT(r, ONE)  | 
    73   | 
    73   | 
    74 //evil regular expressions  | 
    74 //evil regular expressions  | 
    75 def EVIL1(n: Int) = SEQ(NTIMES(OPT(CHAR('a')), n), NTIMES(CHAR('a'), n)) | 
    75 def EVIL1(n: Int) = SEQ(NTIMES(OPT(CHAR('a')), n), NTIMES(CHAR('a'), n)) | 
    76 val EVIL2 = SEQ(STAR(STAR(CHAR('a'))), CHAR('b')) | 
    76 val EVIL2 = SEQ(STAR(STAR(CHAR('a'))), CHAR('b')) | 
    77   | 
    77 val EVIL3 = SEQ(STAR(ALT(CHAR('a'), SEQ(CHAR('a'),CHAR('a')))), CHAR('b')) | 
    78   | 
    78   | 
    79 def time_needed[T](i: Int, code: => T) = { | 
    79 def time_needed[T](i: Int, code: => T) = { | 
    80   val start = System.nanoTime()  | 
    80   val start = System.nanoTime()  | 
    81   for (j <- 1 to i) code  | 
    81   for (j <- 1 to i) code  | 
    82   val end = System.nanoTime()  | 
    82   val end = System.nanoTime()  | 
    92 for (i <- 1 to 8001 by 1000) { | 
    92 for (i <- 1 to 8001 by 1000) { | 
    93   println(i + " " + "%.5f".format(time_needed(2, matcher(EVIL1(i), "a" * i))))  | 
    93   println(i + " " + "%.5f".format(time_needed(2, matcher(EVIL1(i), "a" * i))))  | 
    94 }  | 
    94 }  | 
    95   | 
    95   | 
    96 //test: (a*)* b  | 
    96 //test: (a*)* b  | 
    97 for (i <- 1 to 7000001 by 500000) { | 
    97 for (i <- 1 to 5000001 by 500000) { | 
    98   println(i + " " + "%.5f".format(time_needed(2, matcher(EVIL2, "a" * i))))  | 
    98   println(i + " " + "%.5f".format(time_needed(2, matcher(EVIL2, "a" * i))))  | 
    99 }  | 
    99 }  | 
   100   | 
   100   | 
   101 for (i <- 1 to 7000001 by 500000) { | 
   101 for (i <- 1 to 5000001 by 500000) { | 
   102   println(i + " " + "%.5f".format(time_needed(2, matcher(EVIL2, "a" * i))))  | 
   102   println(i + " " + "%.5f".format(time_needed(2, matcher(EVIL2, "a" * i))))  | 
   103 }  | 
   103 }  | 
   104   | 
   104   | 
         | 
   105   | 
         | 
   106 val r0 = simp(der('a', EVIL3)) | 
         | 
   107 val r1 = simp(der('a', r0)) | 
         | 
   108 val r2 = simp(der('a', r1)) | 
         | 
   109 val r3 = simp(der('a', r2)) | 
         | 
   110 val r4 = simp(der('a', r3)) | 
         | 
   111 val r5 = simp(der('a', r4)) | 
         | 
   112 val r6 = simp(der('a', r5)) | 
         | 
   113   | 
         | 
   114 //test: (a|aa)* b  | 
         | 
   115 for (i <- 1 to 7001 by 500) { | 
         | 
   116   println(i + " " + "%.5f".format(time_needed(2, matcher(EVIL3, "a" * i ++ "c"))))  | 
         | 
   117 }  | 
         | 
   118   |