14 case class REP(r: Rexp, n: Int) extends Rexp |
15 case class REP(r: Rexp, n: Int) extends Rexp |
15 |
16 |
16 // some convenience for typing in regular expressions |
17 // some convenience for typing in regular expressions |
17 implicit def string2rexp(s : String) : Rexp = STR(s) |
18 implicit def string2rexp(s : String) : Rexp = STR(s) |
18 |
19 |
19 implicit def RexpOps(r: Rexp) = new { |
20 implicit def RexpOps(r: Rexp) : Rexp = new { |
20 def | (s: Rexp) = ALT(r, s) |
21 def | (s: Rexp) = ALT(r, s) |
21 def % = STAR(r) |
22 def % = STAR(r) |
22 def %(n: Int) = REP(r, n) |
23 def %(n: Int) = REP(r, n) |
23 def %%(n: Int) = SEQ(REP(r, n), STAR(r)) |
24 def %%(n: Int) = SEQ(REP(r, n), STAR(r)) |
24 def ? = ALT(EMPTY, r) |
25 def ? = ALT(EMPTY, r) |
25 def unary_! = NOT(r) |
26 def unary_! = NOT(r) |
26 def ~ (s: Rexp) = SEQ(r, s) |
27 def ~ (s: Rexp) = SEQ(r, s) |
27 } |
28 } |
28 |
29 |
29 implicit def stringOps(s: String) = new { |
30 implicit def stringOps(s: String) : Rexp = new { |
30 def | (r: Rexp) = ALT(s, r) |
31 def | (r: Rexp) = ALT(s, r) |
31 def | (r: String) = ALT(s, r) |
32 def | (r: String) = ALT(s, r) |
32 def % = STAR(s) |
33 def % = STAR(s) |
33 def %(n: Int) = REP(s, n) |
34 def %(n: Int) = REP(s, n) |
34 def %%(n: Int) = SEQ(REP(s, n), STAR(s)) |
35 def %%(n: Int) = SEQ(REP(s, n), STAR(s)) |
70 case NOT(r) => NOT(der (c, r)) |
71 case NOT(r) => NOT(der (c, r)) |
71 case REP(r, i) => |
72 case REP(r, i) => |
72 if (i == 0) NULL else SEQ(der(c, r), REP(r, i - 1)) |
73 if (i == 0) NULL else SEQ(der(c, r), REP(r, i - 1)) |
73 } |
74 } |
74 |
75 |
|
76 |
75 // derivative w.r.t. a string (iterates der) |
77 // derivative w.r.t. a string (iterates der) |
76 @tailrec |
78 @tailrec |
77 def ders (s: List[Char], r: Rexp) : Rexp = s match { |
79 def ders (s: List[Char], r: Rexp) : Rexp = s match { |
78 case Nil => r |
80 case Nil => r |
79 case c::s => ders(s, der(c, r)) |
81 case c::s => ders(s, der(c, r)) |