S_grammar.scala
changeset 92 e85600529ca5
parent 91 47f86885d481
child 93 4794759139ea
--- a/S_grammar.scala	Sun Dec 23 00:38:56 2012 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,52 +0,0 @@
-//:load parser3.scala
-
-case class StringParser(s: String) extends Parser[String, String] {
-  def parse(ts: String) = {
-    if (s.length <= ts.length && ts.startsWith(s)) Set((s, ts.drop(s.length)))
-    else Set()
-  }
-}
-
-implicit def string2parser(s: String) = StringParser(s)
-
-def time_needed[T](i: Int, code: => T) = {
-  val start = System.nanoTime()
-  for (j <- 1 to i) code
-  val end = System.nanoTime()
-  (end - start)/(i * 1.0e9)
-}
-
-// unambiguous grammar
-
-lazy val U: Parser[String, String] = 
-  ("1" ~ U) ==> { case (x, y) => "1" + y} || ""  
-
-def test1(i: Int) = {
-  val result = U.parse_all("1" * i)
-  //print(result.size + " ")
-}
-
-for (i <- 1 to 1000 by 50) {
-  print(i + " ")
-  print("%.5f".format(time_needed(1, test1(i))))
-  print("\n")
-}
-
-
-
-// ambiguous grammar
-// n = 16 -> over 35 million parse trees
-
-lazy val S: Parser[String, String] = 
-  ("1" ~ S ~ S) ==> { case ((x, y), z) => "1" + y + z} || ""
-
-def test2(i: Int) = {
-  val result = S.parse_all("1" * i)
-  print(result.size + " ")
-}
-
-for (i <- 1 to 30) {
-  print(i + " ")
-  print("%.5f".format(time_needed(1, test2(i))))
-  print("\n")
-}