149 def lex(r: ARexp, s: List[Char]) : List[Boolean] = s match {

   149 def lex(r: ARexp, s: List[Char]) : List[Boolean] = s match {

   150   case Nil => if (nullable(r)) mkepsBC(r) else throw new Exception("Not matched")

   150   case Nil => if (nullable(r)) mkepsBC(r) else throw new Exception("Not matched")

   151   case c::cs => lex(der(c, r), cs)

   151   case c::cs => lex(der(c, r), cs)

   152 }

   152 }

   153 

   153 

   154 def lexing(r: Rexp, s: String) : Val = decode(r, lex(internalise(r), s.toList))

   155 def lexing(r: Rexp, s: String) : Val = decode(r, lex(internalise(r), s.toList))

   155 

   156 

   156 

   157 

   157 

   158 

   158 def simp(r: ARexp): ARexp = r match {

   159 def simp(r: ARexp): ARexp = r match {

   210   val end = System.nanoTime()

   211   val end = System.nanoTime()

   211   (end - start)/(i * 1.0e9)

   212   (end - start)/(i * 1.0e9)

   212 }

   213 }

   213 

   214 

   214 

   215 

   216 

   220 

   217 val r0 = ("a" | "ab") ~ ("b" | "")

   221 val r0 = ("a" | "ab") ~ ("b" | "")

   218 println(lexing(r0, "ab"))

   223 println(lexing(r0, "ab"))

   219 println(lexing_simp(r0, "ab"))

   224 println(lexing_simp(r0, "ab"))

   220 

   225 

   221 val r1 = ("a" | "ab") ~ ("bcd" | "cd")

   226 val r1 = ("a" | "ab") ~ ("bcd" | "cd")

   222 println(lexing(r1, "abcd"))

   227 println(lexing(r1, "abcd"))