25 case CHAR(d) => if (c == d) ONE else ZERO |
25 case CHAR(d) => if (c == d) ONE else ZERO |
26 case ALT(r1, r2) => ALT(der(c, r1), der(c, r2)) |
26 case ALT(r1, r2) => ALT(der(c, r1), der(c, r2)) |
27 case SEQ(r1, r2) => |
27 case SEQ(r1, r2) => |
28 if (nullable(r1)) ALT(SEQ(der(c, r1), r2), der(c, r2)) |
28 if (nullable(r1)) ALT(SEQ(der(c, r1), r2), der(c, r2)) |
29 else SEQ(der(c, r1), r2) |
29 else SEQ(der(c, r1), r2) |
30 case STAR(r) => SEQ(der(c, r), STAR(r)) |
30 case STAR(r1) => SEQ(der(c, r1), STAR(r1)) |
31 case NTIMES(r, i) => |
31 case NTIMES(r1, i) => |
32 if (i == 0) ZERO else SEQ(der(c, r), NTIMES(r, i - 1)) |
32 if (i == 0) ZERO else SEQ(der(c, r1), NTIMES(r1, i - 1)) |
33 } |
33 } |
34 |
34 |
35 def ders (s: List[Char], r: Rexp) : Rexp = s match { |
35 def ders (s: List[Char], r: Rexp) : Rexp = s match { |
36 case Nil => r |
36 case Nil => r |
37 case c::s => ders(s, der(c, r)) |
37 case c::s => ders(s, der(c, r)) |
43 //optional: one or zero times |
43 //optional: one or zero times |
44 def OPT(r: Rexp) = ALT(r, ONE) |
44 def OPT(r: Rexp) = ALT(r, ONE) |
45 |
45 |
46 //evil regular expressions |
46 //evil regular expressions |
47 def EVIL1(n: Int) = SEQ(NTIMES(OPT(CHAR('a')), n), NTIMES(CHAR('a'), n)) |
47 def EVIL1(n: Int) = SEQ(NTIMES(OPT(CHAR('a')), n), NTIMES(CHAR('a'), n)) |
48 val EVIL2 = SEQ(STAR(CHAR('a')), CHAR('b')) |
48 val EVIL2 = SEQ(STAR(STAR(CHAR('a'))), CHAR('b')) |
49 |
49 |
50 def time_needed[T](i: Int, code: => T) = { |
50 def time_needed[T](i: Int, code: => T) = { |
51 val start = System.nanoTime() |
51 val start = System.nanoTime() |
52 for (j <- 1 to i) code |
52 for (j <- 1 to i) code |
53 val end = System.nanoTime() |
53 val end = System.nanoTime() |
63 for (i <- 1 to 1101 by 100) { |
63 for (i <- 1 to 1101 by 100) { |
64 println(i + " " + "%.5f".format(time_needed(2, matches(EVIL1(i), "a" * i)))) |
64 println(i + " " + "%.5f".format(time_needed(2, matches(EVIL1(i), "a" * i)))) |
65 } |
65 } |
66 |
66 |
67 //test: (a*)* b |
67 //test: (a*)* b |
68 for (i <- 1 to 4501 by 500) { |
68 for (i <- 1 to 20) { |
69 println(i + " " + "%.5f".format(time_needed(2, matches(EVIL2, "a" * i)))) |
69 println(i + " " + "%.5f".format(time_needed(2, matches(EVIL2, "a" * i)))) |
70 } |
70 } |
71 |
71 |
72 for (i <- 1 to 4501 by 500) { |
72 for (i <- 1 to 20) { |
73 println(i + " " + "%.5f".format(time_needed(2, matches(EVIL2, "a" * i)))) |
73 println(i + " " + "%.5f".format(time_needed(2, matches(EVIL2, "a" * i)))) |
74 } |
74 } |
75 |
75 |
76 |
76 |