diff -r 47f86885d481 -r e85600529ca5 parser5.scala
--- a/parser5.scala	Sun Dec 23 00:38:56 2012 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,113 +0,0 @@
-val DIGIT = RANGE("0123456789")
-val NONZERODIGIT = RANGE("123456789")
-
-val NUMBER = ALT(SEQ(NONZERODIGIT, STAR(DIGIT)), "0")
-val LPAREN = CHAR('(')
-val RPAREN = CHAR(')')
-val WHITESPACE = PLUS(RANGE(" \n"))
-val OPS = RANGE("+-*")
-
-// for classifying the strings that have been recognised
-abstract class Token
-case object T_WHITESPACE extends Token
-case class T_NUM(s: String) extends Token
-case class T_OP(s: String) extends Token
-case object T_LPAREN extends Token
-case object T_RPAREN extends Token
-
-val lexing_rules: List[Rule[Token]]= 
-  List((NUMBER, (s) => T_NUM(s.mkString)),
-       (WHITESPACE, (s) => T_WHITESPACE),
-       (LPAREN, (s) => T_LPAREN),
-       (RPAREN, (s) => T_RPAREN),
-       (OPS, (s) => T_OP(s.mkString)))
-
-val Tk = Tokenizer(lexing_rules, List(T_WHITESPACE))
-
-
-// parser combinators with input type I and return type T
-// and memoisation
-
-case class SubList[T](s: List[T], l: Int, h: Int) {
-  def low = l
-  def high = h
-  def length = h - l
-  def sublist(l: Int = l, h: Int = h) = s.slice(l, h)
-  def set(low: Int = l, high: Int = h) = SubList(s, low, high)
-}
-
-type Ctxt[T] = List[(String, SubList[T])]
-
-abstract class Parser[I, T] {
-
-  def parse(ts: SubList[I], ctxt: Ctxt[I]): Set[(T, SubList[I])]
-
-  def parse_all(s: List[I]) : Set[T] =
-    for ((head, tail) <- parse(SubList(s, 0, s.length), Nil); if (tail.sublist() == Nil)) yield head
-
-  def || (right : => Parser[I, T]) : Parser[I, T] = new AltParser(this, right)
-  def ==>[S] (f: => T => S) : Parser [I, S] = new FunParser(this, f)
-  def ~[S] (right : => Parser[I, S]) : Parser[I, (T, S)] = new SeqParser(this, right)
-  def ~>[S] (right : => Parser[I, S]) : Parser[I, S] = this ~ right ==> (_._2)
-  def <~[S] (right : => Parser[I, S]) : Parser[I, T] = this ~ right ==> (_._1)
-}
-
-class SeqParser[I, T, S](p: => Parser[I, T], q: => Parser[I, S]) extends Parser[I, (T, S)] {
-  def parse(sb: SubList[I], ctxt: Ctxt[I]) = 
-    for ((head1, tail1) <- p.parse(sb, ctxt); 
-         (head2, tail2) <- q.parse(tail1, ctxt)) yield ((head1, head2), tail2)
-}
-
-class AltParser[I, T](p: => Parser[I, T], q: => Parser[I, T]) extends Parser[I, T] {
-  def parse(sb: SubList[I], ctxt: Ctxt[I]) = p.parse(sb, ctxt) ++ q.parse(sb, ctxt)   
-}
-
-class FunParser[I, T, S](p: => Parser[I, T], f: T => S) extends Parser[I, S] {
-  def parse(sb: SubList[I], ctxt: Ctxt[I]) = 
-    for ((head, tail) <- p.parse(sb, ctxt)) yield (f(head), tail)
-}
-
-case object NumParser extends Parser[Token, Int] {
-  def parse(sb: SubList[Token], ctxt: Ctxt[Token]) = {
-    if (0 < sb.length) sb.sublist(sb.low, sb.low + 1) match { 
-      case T_NUM(i)::Nil => Set((i.toInt, sb.set(low = sb.low + 1))) 
-      case _ => Set()
-    }
-    else Set()
-  }
-}
-
-case class TokParser(t: Token) extends Parser[Token, Token] {
-  def parse(sb: SubList[Token], ctxt: Ctxt[Token]) = {
-    if (0 < sb.length && sb.sublist(sb.low, sb.low + 1) == List(t)) Set((t, sb.set(low = sb.low + 1))) 
-    else Set()
-  }
-}
-
-implicit def token2tparser(t: Token) = TokParser(t)
-
-class IgnLst[I, T](p: => Parser[I, T]) extends Parser[I, T] {
-  def parse(sb: SubList[I], ctxt: Ctxt[I]) = {
-    if (sb.length == 0) Set()
-    else for ((head, tail) <- p.parse(sb.set(high = sb.high - 1), ctxt)) 
-         yield (head, tail.set(high = tail.high + 1))
-  }
-}
-
-class CHECK[I, T](nt: String, p: => Parser[I, T]) extends Parser[I, T] {
-  def parse(sb: SubList[I], ctxt: Ctxt[I]) = {
-    val should_trim = ctxt.contains (nt, sb)
-    if (should_trim && sb.length == 0) Set()
-    else if (should_trim) new IgnLst(p).parse(sb, (nt, sb)::ctxt)
-    else p.parse(sb, (nt, sb)::ctxt)
-  }
-}
-
-lazy val E: Parser[Token, Int] = 
-  new CHECK("E", (E ~ T_OP("+") ~ E) ==> { case ((x, y), z) => x + z} || 
-                 (E ~ T_OP("*") ~ E) ==> { case ((x, y), z) => x * z} ||
-                 (T_LPAREN ~ E ~ T_RPAREN) ==> { case ((x, y), z) => y} ||
-                 NumParser)
-
-println(E.parse_all(Tk.fromString("1 + 2 * 3")))
-println(E.parse_all(Tk.fromString("(1 + 2) * 3")))