new version of combinator parsers

10 files changed, 1112 insertions, 0 deletions

diff --git a/src/library/scala/util/parsing/combinator1/$tilde.scala b/src/library/scala/util/parsing/combinator1/$tilde.scala
new file mode 100644
index 0000000000..25694c1488
--- /dev/null
+++ b/src/library/scala/util/parsing/combinator1/$tilde.scala
@@ -0,0 +1,18 @@
+package scala.util.parsing.combinator1
+
+// p ~ q ~ r ^^ {case a ~ b ~ c => }
+case class ~[+a, +b](_1: a, _2: b) {
+  override def toString = "("+ _1 +" ~ "+ _2 +")"
+}
+
+// shortcut for scala.util.parsing.combinator.~(_, _) -- just ~(_, _) resolves to unary_~
+object mkTilde { def apply[a, b](_1: a, _2: b) = scala.util.parsing.combinator.~(_1, _2) }
+
+
+  //def flatten[t, s <: (~[t, s] \/ t)](p: ~[t, s]): List[t] = p match {
+  //  case hd ~ tl => hd :: flatten(tl)
+  //  case a ~ b => List(a, b)
+  //}
+  //def flatten[t, s <: ~[t, s]](p: ~[t, s]): List[t] = p._1 :: flatten(p)
+  //def flatten[t](p: ~[t, t]): List[t] = List(p._1, p._2)
+
diff --git a/src/library/scala/util/parsing/combinator1/ImplicitConversions.scala b/src/library/scala/util/parsing/combinator1/ImplicitConversions.scala
new file mode 100644
index 0000000000..dc21fa0b87
--- /dev/null
+++ b/src/library/scala/util/parsing/combinator1/ImplicitConversions.scala
@@ -0,0 +1,36 @@
+/*                     __                                               *\
+**     ________ ___   / /  ___     Scala API                            **
+**    / __/ __// _ | / /  / _ |    (c) 2006-2007, LAMP/EPFL             **
+**  __\ \/ /__/ __ |/ /__/ __ |                                         **
+** /____/\___/_/ |_/____/_/ | |                                         **
+**                          |/                                          **
+\*                                                                      */
+
+package scala.util.parsing.combinator1
+
+/** This object contains implicit conversions that come in handy when using the `^^' combinator
+ * {@see Parsers} to construct an AST from the concrete syntax.
+ *<p>
+ * The reason for this is that the sequential composition combinator (`~') combines its constituents
+ * into a ~. When several `~'s are combined, this results in nested `~'s (to the left).
+ * The `flatten*' coercions makes it easy to apply an `n'-argument function to a nested ~ of
+ * depth (`n-1')</p>
+ *<p>
+ * The `headOptionTailToFunList' converts a function that takes a List[A] to a function that
+ * accepts a ~[A, Option[List[A]]] (this happens when, e.g., parsing something of the following
+ * shape: p ~ opt("." ~ repsep(p, ".")) -- where `p' is a parser that yields an A)</p>
+ *
+ * @author Martin Odersky, Iulian Dragos, Adriaan Moors
+ */
+trait ImplicitConversions { self: Parsers =>
+  implicit def flatten2[A, B, C]         (f: (A, B) => C) =
+    (p: ~[A, B]) => p match {case a ~ b => f(a, b)}
+  implicit def flatten3[A, B, C, D]      (f: (A, B, C) => D) =
+    (p: ~[~[A, B], C]) => p match {case a ~ b ~ c => f(a, b, c)}
+  implicit def flatten4[A, B, C, D, E]   (f: (A, B, C, D) => E) =
+    (p: ~[~[~[A, B], C], D]) => p match {case a ~ b ~ c ~ d => f(a, b, c, d)}
+  implicit def flatten5[A, B, C, D, E, F](f: (A, B, C, D, E) => F) =
+    (p: ~[~[~[~[A, B], C], D], E]) => p match {case a ~ b ~ c ~ d ~ e=> f(a, b, c, d, e)}
+  implicit def headOptionTailToFunList[A, T] (f: List[A] => T)=
+    (p: ~[A, Option[List[A]]]) => f(p._1 :: (p._2 match { case Some(xs) => xs case None => Nil}))
+}
diff --git a/src/library/scala/util/parsing/combinator1/Parsers.scala b/src/library/scala/util/parsing/combinator1/Parsers.scala
new file mode 100644
index 0000000000..872ec97009
--- /dev/null
+++ b/src/library/scala/util/parsing/combinator1/Parsers.scala
@@ -0,0 +1,675 @@
+/*                     __                                               *\
+**     ________ ___   / /  ___     Scala API                            **
+**    / __/ __// _ | / /  / _ |    (c) 2006-2007, LAMP/EPFL             **
+**  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
+** /____/\___/_/ |_/____/_/ | |                                         **
+**                          |/                                          **
+\*                                                                      */
+
+// $Id: Parsers.scala 12357 2007-07-18 21:55:08Z moors $
+
+package scala.util.parsing.combinator1
+
+import scala.util.parsing.input._
+import scala.collection.mutable.{Map=>MutableMap}
+
+// TODO: better error handling (labelling like parsec's <?>)
+// TODO: memoisation (like packrat parsers?)
+
+/** <p>
+ *    <code>Parsers</code> is a component that <i>provides</i> generic
+ *    parser combinators.
+ *  </p>
+ *  <p>
+ *    It <i>requires</i> the type of the elements these parsers should parse
+ *    (each parser is polymorphic in the type of result it produces).
+ *  </p>
+ *  <p>
+ *    There are two aspects to the result of a parser: (1) success or failure,
+ *    and (2) the result. A <code>Parser[T]</code> provides both kinds of
+ *    information.
+ *  </p>
+ *  <p>
+ *    The term ``parser combinator'' refers to the fact that these parsers
+ *    are constructed from primitive parsers and composition operators, such
+ *    as sequencing, alternation, optionality, repetition, lifting, and so on.
+ *  </p>
+ *  <p>
+ *    A ``primitive parser'' is a parser that accepts or rejects a single
+ *    piece of input, based on a certain criterion, such as whether the
+ *    input...
+ *  </p><ul>
+ *    <li> is equal to some given object, </li>
+ *    <li> satisfies a certain predicate, </li>
+ *    <li> is in the domain of a given partial function,.... </li>
+ *  </ul>
+ *  <p>
+ *    Even more primitive parsers always produce the same result, irrespective
+ *    of the input.
+ *  </p>
+ *
+ * @requires Elem the type of elements the provided parsers consume
+ *              (When consuming invidual characters, a parser is typically called a ``scanner'',
+ *               which produces ``tokens'' that are consumed by what is normally called a ``parser''.
+ *               Nonetheless, the same principles apply, regardless of the input type.)</p>
+ *<p>
+ * @provides Input = Reader[Elem]
+ *              The type of input the parsers in this component expect.</p>
+ *<p>
+ * @provides Parser[+T] extends (Input => ParseResult[T])
+ *              Essentially, a `Parser[T]' is a function from `Input' to `ParseResult[T]'.</p>
+ *<p>
+ * @provides ParseResult[+T] is like an `Option[T]', in the sense that it is either
+ *              `Success[T]', which consists of some result (:T) (and the rest of the input) or
+ *              `Failure[T]', which provides an error message (and the rest of the input).</p>
+ *
+ * @author Martin Odersky, Iulian Dragos, Adriaan Moors
+ */
+trait Parsers {
+  /** the type of input elements */
+  type Elem
+
+  /** The parser input is an abstract reader of input elements */
+  type Input = Reader[Elem]
+
+  /** A base class for parser results.
+   *  A result is either successful or not (failure may be fatal, i.e.,
+   *  an Error, or not, i.e., a Failure)
+   *  On success, provides a result of type <code>T</code>.
+   */
+  sealed abstract class ParseResult[+T] {
+    /** Functional composition of ParseResults
+     *
+     * @param `f' the function to be lifted over this result
+     * @return `f' applied to the result of this `ParseResult', packaged up as a new `ParseResult'
+     */
+    def map[U](f: T => U): ParseResult[U]
+
+    /** Partial functional composition of ParseResults
+     *
+     * @param `f' the partial function to be lifted over this result
+     * @param error a function that takes the same argument as `f' and produces an error message
+     *        to explain why `f' wasn't applicable (it is called when this is the case)
+     * @return <i>if `f' f is defined at the result in this `ParseResult',</i>
+     *         `f' applied to the result of this `ParseResult', packaged up as a new `ParseResult'.
+     *         If `f' is not defined, `Failure'.
+     */
+    def mapPartial[U](f: PartialFunction[T, U], error: T => String): ParseResult[U]
+
+    def isEmpty = !successful
+
+    /** Returns the embedded result */
+    def get: T
+
+    def getOrElse[B >: T](default: => B): B =
+        if (isEmpty) default else this.get
+
+    val next: Input
+
+    val successful: Boolean
+  }
+
+  /** The success case of ParseResult: contains the result and the remaining input.
+   *
+   *  @param result The parser's output
+   *  @param next   The parser's remaining input
+   */
+  case class Success[+T](result: T, override val next: Input) extends ParseResult[T] {
+    def map[U](f: T => U) = Success(f(result), next)
+    def mapPartial[U](f: PartialFunction[T, U], error: T => String): ParseResult[U]
+       = if(f.isDefinedAt(result)) Success(f(result), next)
+         else Failure(error(result), next)
+
+    def get: T = result
+
+    /** The toString method of a Success */
+    override def toString = "["+next.pos+"] parsed: "+result
+
+    val successful = true
+  }
+
+  /** A common super-class for unsuccessful parse results
+   */
+  sealed abstract class NoSuccess(val msg: String, override val next: Input) extends ParseResult[Nothing] { // when we don't care about the difference between Failure and Error
+    val successful = false
+
+    def map[U](f: Nothing => U) = this
+    def mapPartial[U](f: PartialFunction[Nothing, U], error: Nothing => String): ParseResult[U] = this
+
+    def get: Nothing = error("No result when parsing failed")
+  }
+
+  /** The failure case of ParseResult: contains an error-message and the remaining input.
+   * Parsing will back-track when a failure occurs.
+   *
+   *  @param msg    An error message string describing the failure.
+   *  @param next   The parser's unconsumed input at the point where the failure occurred.
+   */
+  case class Failure(override val msg: String, override val next: Input) extends NoSuccess(msg, next) {
+    /** The toString method of a Failure yields an error message */
+    override def toString = "["+next.pos+"] failure: "+msg+"\n\n"+next.pos.longString
+  }
+
+  /** The fatal failure case of ParseResult: contains an error-message and the remaining input.
+   * No back-tracking is done when a parser returns an `Error'
+   *
+   *  @param msg    An error message string describing the error.
+   *  @param next   The parser's unconsumed input at the point where the error occurred.
+   */
+  case class Error(override val msg: String, override val next: Input) extends NoSuccess(msg, next) {
+    /** The toString method of an Error yields an error message */
+    override def toString = "["+next.pos+"] error: "+msg+"\n\n"+next.pos.longString
+  }
+
+  /** The root class of parsers.
+   *  Parsers are functions from the Input type to ParseResult
+   */
+  abstract class Parser[+T] extends (Input => ParseResult[T]) {
+    /** An unspecified method that defines the behaviour of this parser.
+     */
+    def apply(in: Input): ParseResult[T]
+
+
+    // the operator formerly known as +++, ++, &, but now, behold the venerable ~
+    // it's short, light (looks like whitespace), has few overloaded meaning (thanks to the recent change from ~ to unary_~)
+    // and we love it!
+
+    /** A parser combinator for sequential composition
+     *
+     * <p> `p ~ q' succeeds if `p' succeeds and `q' succeeds on the input
+     *          left over by `p'.</p>
+     *
+     * @param q a parser that will be executed after `p' (this parser) succeeds
+     * @return a `Parser' that -- on success -- returns a `~' (like a Pair, but easier to pattern match on)
+     *         that contains the result of `p' and that of `q'.
+     *         The resulting parser fails if either `p' or `q' fails.
+     */
+    def ~ [U](q: => Parser[U]): Parser[~[T, U]] = new Parser[~[T, U]] {
+      def apply(in: Input) = seq(Parser.this, q)((x, y) => new ~(x,y))(in)
+      override def toString = "~"
+    }
+
+    def ~> [U](q: => Parser[U]): Parser[U] = new Parser[U] {
+      def apply(in: Input) = seq(Parser.this, q)((x, y) => y)(in)
+      override def toString = "~"
+    }
+
+    def <~ [U](q: => Parser[U]): Parser[T] = new Parser[T] {
+      def apply(in: Input) = seq(Parser.this, q)((x, y) => x)(in)
+      override def toString = "~"
+    }
+
+     /* not really useful: V cannot be inferred because Parser is covariant in first type parameter (V is always trivially Nothing)
+    def ~~ [U, V](q: => Parser[U])(implicit combine: (T, U) => V): Parser[V] = new Parser[V] {
+      def apply(in: Input) = seq(Parser.this, q)((x, y) => combine(x,y))(in)
+    }  */
+
+    /** A parser combinator for non-back-tracking sequential composition
+     *
+     *<p>`p ~! q' succeeds if `p' succeeds and `q' succeeds on the input
+     *          left over by `p'. In case of failure, no back-tracking is performed
+     *          (in an earlier parser produced by the | combinator).</p>
+     *
+     * @param q a parser that will be executed after `p' (this parser) succeeds
+     * @return a `Parser' that -- on success -- returns a `~' (like a Pair, but easier to pattern match on)
+     *         that contains the result of `p' and that of `q'.
+     *         The resulting parser fails if either `p' or `q' fails, this failure is fatal.
+     */
+    def ~! [U](q: => Parser[U]): Parser[~[T, U]] = new Parser[~[T, U]] with OnceParser[~[T, U]] {
+      def apply(in: Input) = seq(Parser.this, commit(q))((x, y) => new ~(x,y))(in)
+      override def toString = "~!"
+    }
+
+    /** A parser combinator for alternative composition
+     *
+     *<p>`p | q' succeeds if `p' succeeds or `q' succeeds
+     *          Note that `q' is only tried if `p's failure is non-fatal (i.e., back-tracking is
+     *          allowed).</p>
+     *
+     * @param q a parser that will be executed if `p' (this parser) fails (and allows back-tracking)
+     * @return a `Parser' that returns the result of the first parser to succeed (out of `p' and `q')
+     *         The resulting parser succeeds if (and only if) <ul>
+     *           <li> `p' succeeds, <i>or</i>  </li>
+     *           <li> if `p' fails allowing back-tracking and `q' succeeds. </li> </ul>
+     */
+    def | [U >: T](q: => Parser[U]): Parser[U] = new Parser[U] {
+      def apply(in: Input) = Parser.this(in) match {
+        case s1 @ Success(_, _) => s1
+        case e1 @ Error(_, _) => e1
+        case f1 @ Failure(_, next1) => q(in) match {
+              case s2 @ Success(_, _) => s2
+              case f2 @ Failure(_, next2) => if (next2.pos < next1.pos) f1 else f2
+              case e2 @ Error(_, next2) => if (next2.pos < next1.pos) f1 else e2
+        }
+      }
+      override def toString = "|"
+    }
+
+    /** A parser combinator for function application
+     *
+     *<p>`p ^^ f' succeeds if `p' succeeds; it returns `f' applied to the result of `p'.</p>
+     *
+     * @param f a function that will be applied to this parser's result (see `map' in `ParseResult').
+     * @return a parser that has the same behaviour as the current parser, but whose result is
+     *         transformed by `f'.
+     */
+    def ^^ [U](f: T => U): Parser[U] = new Parser[U] {
+      def apply(in: Input) = Parser.this(in).map(f)
+      override def toString = Parser.this.toString+"^^"
+    }
+
+    def ^^^ [U](r: U): Parser[U] = ^^ (x => r)
+
+    /** A parser combinator for partial function application
+     *
+     *<p>`p ^? (f, error)' succeeds if `p' succeeds AND `f' is defined at the result of `p';
+     *  in that case, it returns `f' applied to the result of `p'. If `f' is not applicable,
+     *  error(the result of `p') should explain why.</p>
+     *
+     * @param f a partial function that will be applied to this parser's result
+     *          (see `mapPartial' in `ParseResult').
+     * @param error a function that takes the same argument as `f' and produces an error message
+     *        to explain why `f' wasn't applicable
+     * @return a parser that succeeds if the current parser succeeds <i>and</i> `f' is applicable
+     *         to the result. If so, the result will be transformed by `f'.
+     */
+    def ^? [U](f: PartialFunction[T, U], error: T => String): Parser[U] = new Parser[U] {
+      def apply(in: Input) = Parser.this(in).mapPartial(f, error)
+      override def toString = Parser.this.toString+"^?"
+    }
+
+    /** A parser combinator for partial function application
+     *
+     *<p>`p ^? f' succeeds if `p' succeeds AND `f' is defined at the result of `p';
+     *  in that case, it returns `f' applied to the result of `p'.</p>
+     *
+     * @param f a partial function that will be applied to this parser's result
+     *          (see `mapPartial' in `ParseResult').
+     * @return a parser that succeeds if the current parser succeeds <i>and</i> `f' is applicable
+     *         to the result. If so, the result will be transformed by `f'.
+     */
+    def ^? [U](f: PartialFunction[T, U]): Parser[U] = new Parser[U] {
+      def apply(in: Input) = Parser.this(in).mapPartial(f, result => "Constructor function not defined at "+result)
+      override def toString = Parser.this.toString+"^?"
+    }
+
+
+    /** A parser combinator that parameterises a subsequent parser with the result of this one
+     *
+     *<p>
+     * Use this combinator when a parser depends on the result of a previous parser. `p' should be
+     * a function that takes the result from the first parser and returns the second parser.</p>
+     *
+     *<p> `p into fq' (with `fq' typically `{x => q}') first applies `p', and then, if `p' successfully
+     *    returned result `r', applies `fq(r)' to the rest of the input. </p>
+     *
+     *<p> From: G. Hutton. Higher-order functions for parsing. J. Funct. Program., 2(3):323--343, 1992. </p>
+     *
+     * @param fq a function that, given the result from this parser, returns the second parser to be applied
+     * @return a parser that succeeds if this parser succeeds (with result `x') and if then `fq(x)' succeeds
+     */
+    def into[U](fq: T => Parser[U]): Parser[U] = new Parser[U] {
+       def apply(in: Input) = Parser.this(in) match {
+         case Success(result, next) => fq(result)(next)
+         case ns: NoSuccess => ns
+       }
+     }
+
+    // shortcuts for combinators:
+
+    /** Returns into(fq) */
+    def >>[U](fq: T => Parser[U])=into(fq)
+
+
+    /** Returns a parser that repeatedly parses what this parser parses
+     *
+     * @return rep(this)
+     */
+    def * = rep(this)
+
+    /** Returns a parser that repeatedly parses what this parser parses, interleaved with the `sep' parser.
+     * The `sep' parser specifies how the results parsed by this parser should be combined.
+     *
+     * @return chainl1(this, sep)
+     */
+    def *[U >: T](sep: => Parser[(U, U) => U]) = chainl1(this, sep)
+
+    // TODO: improve precedence? a ~ b*(",") = a ~ (b*(","))  should be true
+
+    /** Returns a parser that repeatedly (at least once) parses what this parser parses.
+     *
+     * @return rep1(this)
+     */
+    def + = rep1(this)
+
+    /** Returns a parser that optionally parses what this parser parses.
+     *
+     * @return opt(this)
+     */
+    def ? = opt(this)
+  }
+
+  // TODO: can this implemented in ParseResult, like map?
+  /** A helper method for sequential composition of (unit-)parsers
+  */
+  private def seq[T, U, V](p: => Input => ParseResult[T], q: => Input => ParseResult[U])
+                          (compose: (T, U) => V)
+                          (in: Input): ParseResult[V]
+    = p(in) match {
+      case Success(x, next1) => q(next1) match {
+          case Success(y, next2) => Success(compose(x, y), next2)
+          case ns: NoSuccess => ns
+        }
+      case ns: NoSuccess => ns
+    }
+
+  /** Wrap a parser so that its failures become errors (the | combinator will give up as soon as
+   *  it encounters an error, on failure it simply tries the next alternative)
+   */
+  def commit[T](p: => Parser[T]) = new Parser[T] {
+    def apply(in: Input) = p(in) match{
+      case s @ Success(_, _) => s
+      case e @ Error(_, _) => e
+      case f @ Failure(msg, next) => Error(msg, next)
+    }
+  }
+
+	/*trait ElemFun
+  case class EFCons(hd: Elem => ElemFun, tl: ElemFun) extends ElemFun
+  case class EFNil(res: Boolean) extends ElemFun*/
+
+
+  /** A parser matching input elements that satisfy a given predicate
+   *
+   * <p>elem(kind, p) succeeds if the input starts with an element `e' for which p(e) is true.</p>
+   *
+   * @param  kind   The element kind, used for error messages
+   * @param  p      A predicate that determines which elements match.
+   * @return
+   */
+  def elem(kind: String, p: Elem => Boolean) = new Parser[Elem] {
+    def apply(in: Input) =
+      if (p(in.first)) Success(in.first, in.rest)
+      else Failure(kind+" expected", in)
+  }
+
+  /** A parser that matches only the given element `e'
+   *
+   * <p>elem(e) succeeds if the input starts with an element `e'</p>
+   *
+   * @param e the `Elem' that must be the next piece of input for the returned parser to succeed
+   * @return a `Parser' that succeeds if `e' is the next available input (and returns it).
+   */
+  def elem(e: Elem): Parser[Elem] = new Parser[Elem] {
+    def apply(in: Input) =
+      if (in.first == e) Success(e, in.rest)
+      else Failure("`"+e+"' expected but " + in.first + " found", in)
+  }
+
+
+  /** A parser that matches only the given element `e'
+   *<p>
+   * The method is implicit so that elements can automatically be lifted to their parsers.
+   * For example, when parsing `Token's, Identifier("new") (which is a `Token') can be used directly,
+   * instead of first creating a `Parser' using accept(Identifier("new")).</p>
+   *
+   * @param e the `Elem' that must be the next piece of input for the returned parser to succeed
+   * @return a `tParser' that succeeds if `e' is the next available input.
+   */
+  implicit def accept(e: Elem): Parser[Elem] = new Parser[Elem] {
+    def apply(in: Input) =
+      if (in.first == e) Success(e, in.rest)
+      else Failure("`"+e+"' expected but " + in.first + " found", in)
+  }
+
+  /** A parser that matches only the given list of element `es'
+   *
+   * <p>accept(es) succeeds if the input subsequently provides the elements in the list `es'.</p>
+   *
+   * @param  es the list of expected elements
+   * @return a Parser that recognizes a specified list of elements
+   */
+  def accept[ES <% List[Elem]](es: ES) = new Parser[List[Elem]] {
+    def apply(in0: Input) = {
+      var these: List[Elem] = es
+      var in = in0
+
+      while(!these.isEmpty && in.first == these.head) {
+        these = these.tail
+        in = in.rest
+      }
+
+      if (these.isEmpty) Success(es: List[Elem], in)
+      else Failure("Expected: '"+these.head+"', found: '"+in.first+"'", in0)
+    }
+  }
+
+  /** The parser that matches an element in the domain of the partial function `f'
+   *<p>
+   * If `f' is defined on the first element in the input, `f' is applied to it to produce
+   * this parser's result.</p>
+   *<p>
+   * Example: The parser <code>accept("name", {case Identifier(n) => Name(n)})</code>
+   *          accepts an <code>Identifier(n)</code> and returns a <code>Name(n)</code>.</p>
+   *
+   * @param expected a description of the kind of element this parser expects (for error messages)
+   * @param f a partial function that determines when this parser is successful and what its output is
+   * @return A parser that succeeds if `f' is applicable to the first element of the input,
+   *         applying `f' to it to produce the result.
+   */
+  def accept[U](expected: String, f: PartialFunction[Elem, U]): Parser[U] = new Parser[U] {
+    def apply(in: Input) =
+      if (f.isDefinedAt(in.first)) Success(f(in.first), in.rest)
+      else Failure(expected+" expected", in)
+  }
+
+  /** A parser that always fails
+   *
+   * @param msg The error message describing the failure.
+   * @return A parser that always fails with the specified error message.
+   */
+  def failure(msg: String) = new Parser[Nothing] {
+    def apply(in: Input) = Failure(msg, in)
+  }
+
+  /** A parser that results in an error
+   *
+   * @param msg The error message describing the failure.
+   * @return A parser that always fails with the specified error message.
+   */
+  def err(msg: String) = new Parser[Nothing] {
+    def apply(in: Input) = Error(msg, in)
+  }
+
+  /** A parser that always succeeds
+   *
+   * @param v The result for the parser
+   * @return A parser that always succeeds, with the given result `v'
+   */
+  def success[T](v: T) = new Parser[T] {
+    def apply(in: Input) = Success(v, in)
+  }
+
+  def log[T](p: => Parser[T])(name: String): Parser[T] = new Parser[T] {
+    def apply(in: Input) = {println("trying "+name+" at "+in.pos); val r = p(in); println(name+" --> "+r); r }
+  }
+
+  /** A parser generator for repetitions.
+   *
+   * <p> rep(p)   repeatedly uses `p' to parse the input until `p' fails (the result is a List
+   *  of the consecutive results of `p') </p>
+   *
+   * @param p a `Parser' that is to be applied successively to the input
+   * @return A parser that returns a list of results produced by repeatedly applying `p' to the input.
+   */
+  def rep[T](p: => Parser[T]): Parser[List[T]] = rep1(p) | success(List())
+
+  /** A parser generator for interleaved repetitions.
+   *
+   * <p> repsep(p, q)   repeatedly uses `p' interleaved with `q' to parse the input, until `p' fails.
+   *  (The result is a `List' of the results of `p'.) </p>
+   *
+   * <p>Example: <code>repsep(term, ",")</code> parses a comma-separated list of term's,
+   *          yielding a list of these terms</p>
+   *
+   * @param p a `Parser' that is to be applied successively to the input
+   * @param q a `Parser' that parses the elements that separate the elements parsed by `p'
+   * @return A parser that returns a list of results produced by repeatedly applying `p' (interleaved
+   *         with `q') to the input.
+   *         The results of `p' are collected in a list. The results of `q' are discarded.
+   */
+  def repsep[T](p: => Parser[T], q: => Parser[Any]): Parser[List[T]] =
+    rep1sep(p, q) | success(List())
+
+  /** A parser generator for non-empty repetitions.
+   *
+   * <p> rep1(p) repeatedly uses `p' to parse the input until `p' fails -- `p' must succeed at least
+   *             once (the result is a `List' of the consecutive results of `p')</p>
+   *
+   * @param p a `Parser' that is to be applied successively to the input
+   * @return A parser that returns a list of results produced by repeatedly applying `p' to the input
+   *        (and that only succeeds if `p' matches at least once).
+   */
+  def rep1[T](p: => Parser[T]): Parser[List[T]] = rep1(p, p)
+
+  /** A parser generator for non-empty repetitions.
+   *
+   * <p> rep1(f, p) first uses `f' (which must succeed) and then repeatedly uses `p' to
+   *     parse the input until `p' fails
+   *     (the result is a `List' of the consecutive results of `f' and `p')</p>
+   *
+   * @param first a `Parser' that parses the first piece of input
+   * @param p a `Parser' that is to be applied successively to the rest of the input (if any)
+   * @return A parser that returns a list of results produced by first applying `f' and then
+   *         repeatedly `p' to the input (it only succeeds if `f' matches).
+   */
+  def rep1[T](first: => Parser[T], p: => Parser[T]): Parser[List[T]] = first ~ rep(p) ^^ { case ~(x, xs) => x :: xs }
+
+  /* new Parser[List[T]] {
+    def apply(in0: Input) = {
+      val xs = new scala.collection.mutable.ListBuffer[T]
+      var in = in0
+
+      var res = first(in)
+
+      while(res.successful) {
+        xs += res.get
+        in = res.next
+        res = p(in)
+      }
+
+      if (!xs.isEmpty) Success(xs.toList, res.next)
+      else Failure("TODO", TODO)
+    }
+  }*/
+
+  /** A parser generator for a specified number of repetitions.
+   *
+   * <p> repN(n, p)  uses `p' exactly `n' time to parse the input
+   *       (the result is a `List' of the `n' consecutive results of `p')</p>
+   *
+   * @param p a `Parser' that is to be applied successively to the input
+   * @param n the exact number of times `p' must succeed
+   * @return A parser that returns a list of results produced by repeatedly applying `p' to the input
+   *        (and that only succeeds if `p' matches exactly `n' times).
+   */
+  def repN[T](n: Int, p: => Parser[T]): Parser[List[T]] =
+    if(n==0) success(Nil) else p ~ repN(n-1, p) ^^ { case ~(x, xs) => x :: xs }
+
+  /** A parser generator for non-empty repetitions.
+   *
+   *  <p>rep1sep(first, p, q) starts by using `first', followed by repeatedly uses of `p' interleaved with `q'
+   *                to parse the input, until `p' fails. `first' must succeed (the result is a `List' of the
+   *                consecutive results of `first' and `p')</p>
+   *
+   * @param first a `Parser' that is to be applied to the first element of input
+   * @param p a `Parser' that is to be applied successively to the input
+   * @param q a `Parser' that parses the elements that separate the elements parsed by `p'
+   *          (interleaved with `q')
+   * @return A parser that returns a list of results produced by repeatedly applying `p' to the input
+   *         (and that only succeeds if `p' matches at least once).
+   *         The results of `p' are collected in a list. The results of `q' are discarded.
+   */
+  def rep1sep[T](p: => Parser[T], q: => Parser[Any]): Parser[List[T]] =
+    p ~ (q ~ rep1sep(p, q) ^^ { case x ~ y => y } | success(List())) ^^ { case x ~ y => x :: y }
+
+  /** A parser generator that, roughly, generalises the rep1sep generator so that `q', which parses the separator,
+   * produces a left-associative function that combines the elements it separates.
+   *
+   * <p> From: J. Fokker. Functional parsers. In J. Jeuring and E. Meijer, editors, Advanced Functional Programming, volume 925 of Lecture Notes in Computer Science, pages 1--23. Springer, 1995.</p>
+   *
+   * @param p a parser that parses the elements
+   * @param q a parser that parses the token(s) separating the elements, yielding a left-associative function that
+   *          combines two elements into one
+   */
+  def chainl1[T](p: => Parser[T], q: => Parser[(T, T) => T]): Parser[T] =
+    p ~ rep(q ~ p) ^^ {case x ~ xs => xs.foldLeft(x)((a, f_b) => f_b._1(a, f_b._2))}  // ((a, {f, b}) => f(a, b))
+
+  /** A parser generator that, roughly, generalises the rep1sep generator so that `q', which parses the separator,
+   * produces a left-associative function that combines the elements it separates.
+   *
+   * @param first a parser that parses the first element
+   * @param p a parser that parses the subsequent elements
+   * @param q a parser that parses the token(s) separating the elements, yielding a left-associative function that
+   *          combines two elements into one
+   */
+  def chainl1[T, U](first: => Parser[T], p: => Parser[U], q: => Parser[(T, U) => T]): Parser[T] =
+    first ~ rep(q ~ p) ^^ {case x ~ xs => xs.foldLeft(x)((a, f_b) => f_b._1(a, f_b._2))}  // ((a, {f, b}) => f(a, b))
+
+  /** A parser generator that generalises the rep1sep generator so that `q', which parses the separator,
+   * produces a right-associative function that combines the elements it separates. Additionally,
+   * The right-most (last) element and the left-most combinating function have to be supplied.
+   *
+   * rep1sep(p: Parser[T], q) corresponds to chainr1(p, q ^^ cons, cons, Nil) (where val cons = (x: T, y: List[T]) => x :: y)
+   *
+   * @param p a parser that parses the elements
+   * @param q a parser that parses the token(s) separating the elements, yielding a right-associative function that
+   *          combines two elements into one
+   * @param combine the "last" (left-most) combination function to be applied
+   * @param first   the "first" (right-most) element to be combined
+   */
+  def chainr1[T, U](p: Parser[T], q: Parser[(T, U) => U], combine: (T, U) => U, first: U): Parser[U] =
+    p ~ rep(q ~ p) ^^ {case x ~ xs =>
+                          (new ~(combine, x) :: xs).foldRight(first)((f_a, b) => f_a._1(f_a._2, b))}  // (({f, a}, b) => f(a, b))
+
+  /** A parser generator for optional sub-phrases.
+   *
+   *  <p>opt(p) is a parser that returns `Some(x)' if `p' returns `x' and `None' if `p' fails</p>
+   *
+   * @param p A `Parser' that is tried on the input
+   * @return a `Parser' that always succeeds: either with the result provided by `p' or
+   *         with the empty result
+   */
+  def opt[T](p: => Parser[T]): Parser[Option[T]] =
+    p ^^ (x => Some(x)) | success(None)
+
+  /** `positioned' decorates a parser's result with the start position of the input it consumed.
+   *
+   * @param p a `Parser' whose result conforms to `Positional'.
+   * @return A parser that has the same behaviour as `p', but which marks its result with the
+   *         start position of the input it consumed, if it didn't already have a position.
+   */
+  def positioned[T <: Positional](p: => Parser[T]): Parser[T] = new Parser[T] {
+    def apply(in: Input) = p(in) match {
+      case Success(t, in1) => Success(if (t.pos == NoPosition) t setPos in.pos else t, in1)
+      case ns: NoSuccess => ns
+    }
+  }
+
+  case class ~[+a, +b](_1: a, _2: b) {
+    override def toString = "("+ _1 +" ~ "+ _2 +")"
+  }
+
+  /** A function that always returns a given constant; useful as right-hand argument of ^^
+   */
+
+  def const[T, U] (result: U): T => U = x => result
+
+  /** A parser whose ~ combinator disallows back-tracking.
+   */
+  trait OnceParser[+T] extends Parser[T] {
+    override def ~ [U](q: => Parser[U]): Parser[~[T, U]] = new Parser[~[T, U]] with OnceParser[~[T, U]] {
+      def apply(in: Input) = seq(OnceParser.this, commit(q))((x, y) => new ~(x, y))(in)
+    }
+  }
+}
diff --git a/src/library/scala/util/parsing/combinator1/lexical/Lexical.scala b/src/library/scala/util/parsing/combinator1/lexical/Lexical.scala
new file mode 100644
index 0000000000..31ecdc629d
--- /dev/null
+++ b/src/library/scala/util/parsing/combinator1/lexical/Lexical.scala
@@ -0,0 +1,41 @@
+/*                     __                                               *\
+**     ________ ___   / /  ___     Scala API                            **
+**    / __/ __// _ | / /  / _ |    (c) 2006-2007, LAMP/EPFL             **
+**  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
+** /____/\___/_/ |_/____/_/ | |                                         **
+**                          |/                                          **
+\*                                                                      */
+
+// $Id: Lexical.scala 12268 2007-07-11 13:45:53Z michelou $
+
+
+package scala.util.parsing.combinator1.lexical
+
+import scala.util.parsing.syntax._
+import scala.util.parsing.input.CharArrayReader.EofCh
+
+/** <p>
+ *    This component complements the <code>Scanners</code> component with
+ *    common operations for lexical parsers.
+ *  </p>
+ *  <p>
+ *   {@see StdLexical} for a concrete implementation for a simple, Scala-like
+ *   language.
+ *  </p>
+ *
+ * @author Martin Odersky, Adriaan Moors
+ */
+abstract class Lexical extends Scanners with Tokens {
+
+  /** A character-parser that matches a letter (and returns it)*/
+  def letter = elem("letter", _.isLetter)
+
+  /** A character-parser that matches a digit (and returns it)*/
+  def digit = elem("digit", _.isDigit)
+
+  /** A character-parser that matches any character except the ones given in `cs' (and returns it)*/
+  def chrExcept(cs: Char*) = elem("", ch => (cs forall (ch !=)))
+
+  /** A character-parser that matches a white-space character (and returns it)*/
+  def whitespaceChar = elem("space char", ch => ch <= ' ' && ch != EofCh)
+}
diff --git a/src/library/scala/util/parsing/combinator1/lexical/Scanners.scala b/src/library/scala/util/parsing/combinator1/lexical/Scanners.scala
new file mode 100644
index 0000000000..af5c141267
--- /dev/null
+++ b/src/library/scala/util/parsing/combinator1/lexical/Scanners.scala
@@ -0,0 +1,75 @@
+/*                     __                                               *\
+**     ________ ___   / /  ___     Scala API                            **
+**    / __/ __// _ | / /  / _ |    (c) 2006-2007, LAMP/EPFL             **
+**  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
+** /____/\___/_/ |_/____/_/ | |                                         **
+**                          |/                                          **
+\*                                                                      */
+
+// $Id: Scanners.scala 12407 2007-07-25 02:33:18Z emir $
+
+
+package scala.util.parsing.combinator1.lexical
+
+import scala.util.parsing.syntax._
+import scala.util.parsing.input._
+
+/** <p>
+ *    This component provides core functionality for lexical parsers.
+ *  </p>
+ *  <p>
+ *    See its subclasses {@see Lexical} and -- most interestingly
+ *    {@see StdLexical}, for more functionality.
+ *  </p>
+ *
+ *  @requires token      a parser that produces a token (from a stream of characters)
+ *  @requires whitespace a unit-parser for white-space
+ *  @provides Scanner    essentially a parser that parses a stream of characters
+ *                       to produce `Token's, which are typically passed to a
+ *                       syntactical parser (which operates on `Token's, not on
+ *                       individual characters).
+ *
+ *  @author Martin Odersky, Adriaan Moors
+ */
+trait Scanners extends Parsers {
+  type Elem = Char
+  type Token
+
+  /** This token is produced by a scanner {@see Scanner} when scanning failed. */
+  def errorToken(msg: String): Token
+
+  /** a parser that produces a token (from a stream of characters) */
+  def token: Parser[Token]
+
+  /** a parser for white-space -- its result will be discarded */
+  def whitespace: Parser[Any]
+
+  /** <p>
+   *    <code>Scanner</code> is essentially(*) a parser that produces `Token's
+   *    from a stream of characters. The tokens it produces are typically
+   *    passed to parsers in <code>TokenParsers</code>.
+   *  </p>
+   *  <p>
+   *   Note: (*) <code>Scanner</code> is really a `Reader' of `Token's
+   *  </p>
+   */
+  class Scanner(in: Reader[Char]) extends Reader[Token] {
+    /** Convenience constructor (makes a character reader out of the given string) */
+    def this(in: String) = this(new CharArrayReader(in.toCharArray()))
+    private val (tok, rest1, rest2) = whitespace(in) match {
+      case Success(_, in1) =>
+        token(in1) match {
+          case Success(tok, in2) => (tok, in1, in2)
+          case ns: NoSuccess => (errorToken(ns.msg), ns.next, skip(ns.next))
+        }
+      case ns: NoSuccess => (errorToken(ns.msg), ns.next, skip(ns.next))
+    }
+    private def skip(in: Reader[Char]) = if (in.atEnd) in else in.rest
+
+    def first = tok
+    def rest = new Scanner(rest2)
+    def pos = rest1.pos
+    def atEnd = in.atEnd || (whitespace(in) match { case Success(_, in1) => in1.atEnd case _ => false })
+  }
+}
+
diff --git a/src/library/scala/util/parsing/combinator1/lexical/StdLexical.scala b/src/library/scala/util/parsing/combinator1/lexical/StdLexical.scala
new file mode 100644
index 0000000000..fc04116692
--- /dev/null
+++ b/src/library/scala/util/parsing/combinator1/lexical/StdLexical.scala
@@ -0,0 +1,90 @@
+/*                     __                                               *\
+**     ________ ___   / /  ___     Scala API                            **
+**    / __/ __// _ | / /  / _ |    (c) 2006-2007, LAMP/EPFL             **
+**  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
+** /____/\___/_/ |_/____/_/ | |                                         **
+**                          |/                                          **
+\*                                                                      */
+
+// $Id: StdLexical.scala 12242 2007-07-09 09:43:09Z michelou $
+
+
+package scala.util.parsing.combinator1.lexical
+
+import scala.util.parsing.syntax._
+import scala.util.parsing.input.CharArrayReader.EofCh
+import collection.mutable.HashSet
+
+/** <p>
+ *    This component provides a standard lexical parser for a simple, Scala-like language.
+ *    It parses keywords and identifiers, numeric literals (integers), strings, and delimiters.
+ *  </p>
+ *  <p>
+ *    To distinguish between identifiers and keywords, it uses a set of reserved identifiers:
+ *    every string contained in `reserved' is returned as a keyword token.
+ *    (Note that "=>" is hard-coded as a keyword.)
+ *    Additionally, the kinds of delimiters can be specified by the `delimiters' set.
+ *  </p>
+ *  <p>
+ *    Usually this component is used to break character-based input into bigger tokens,
+ *    which are then passed to a token-parser {@see TokenParsers}.
+ *  </p>
+ *
+ * @author Martin Odersky, Iulian Dragos, Adriaan Moors
+ */
+class StdLexical extends Lexical with StdTokens {
+  // see `token' in `Scanners'
+  def token: Parser[Token] =
+    ( letter ~ rep( letter | digit )                    ^^ { case first ~ rest => processIdent(first :: rest mkString "") }
+    | digit ~ rep( digit )                              ^^ { case first ~ rest => NumericLit(first :: rest mkString "") }
+    | '\'' ~ rep( chrExcept('\'', '\n', EofCh) ) ~ '\'' ^^ { case _ ~ chars ~ _ => StringLit(chars mkString "") }
+    | '\"' ~ rep( chrExcept('\"', '\n', EofCh) ) ~ '\"' ^^ { case _ ~ chars ~ _ => StringLit(chars mkString "") }
+    | EofCh                                             ^^ const(EOF)
+    | '\'' ~> failure("unclosed string literal")
+    | '\"' ~> failure("unclosed string literal")
+    | delim
+    | failure("illegal character")
+    )
+
+  // see `whitespace in `Scanners'
+  def whitespace: Parser[Any] = rep(
+      whitespaceChar
+    | '/' ~ '*' ~ comment
+    | '/' ~ '/' ~ rep( chrExcept(EofCh, '\n') )
+    | '/' ~ '*' ~ failure("unclosed comment")
+    )
+
+  protected def comment: Parser[Any] = (
+      '*' ~ '/'  ^^ { case _ => ' '  }
+    | chrExcept(EofCh) ~ comment
+    )
+
+  /** The set of reserved identifiers: these will be returned as `Keyword's */
+  val reserved = new HashSet[String]
+
+  /** The set of delimiters (ordering does not matter) */
+  val delimiters = new HashSet[String]
+
+  protected def processIdent(name: String) =
+    if (reserved contains name) Keyword(name) else Identifier(name)
+
+  private var _delim: Parser[Token] = null
+  protected def delim: Parser[Token] = {
+    if(_delim eq null) { // construct parser for delimiters by |'ing together the parsers for the individual delimiters,
+    // starting with the longest one (hence the sort + reverse) -- otherwise a delimiter D will never be matched if
+    // there is another delimiter that is a prefix of D
+      def parseDelim(s: String): Parser[Token] = accept(s.toList) ^^ { x => Keyword(s) }
+
+      val d = new Array[String](delimiters.size)
+      delimiters.copyToArray(d,0)
+      scala.util.Sorting.quickSort(d)
+      _delim = d.toList.reverse.map(parseDelim).reduceRight[Parser[Token]](_ | _) // no offence :-)
+    }
+
+    _delim
+  }
+
+  private def lift[T](f: String => T)(xs: List[Char]): T = f(xs.mkString("", "", ""))
+
+  private def lift2[T](f: String => T)(p: ~[Char, List[Char]]): T = lift(f)(p._1 :: p._2)
+}
diff --git a/src/library/scala/util/parsing/combinator1/syntactical/StandardTokenParsers.scala b/src/library/scala/util/parsing/combinator1/syntactical/StandardTokenParsers.scala
new file mode 100644
index 0000000000..68d0d07c39
--- /dev/null
+++ b/src/library/scala/util/parsing/combinator1/syntactical/StandardTokenParsers.scala
@@ -0,0 +1,24 @@
+/*                     __                                               *\
+**     ________ ___   / /  ___     Scala API                            **
+**    / __/ __// _ | / /  / _ |    (c) 2006-2007, LAMP/EPFL             **
+**  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
+** /____/\___/_/ |_/____/_/ | |                                         **
+**                          |/                                          **
+\*                                                                      */
+
+// $Id: StdTokenParsers.scala 12242 2007-07-09 09:43:09Z michelou $
+
+
+package scala.util.parsing.combinator1.syntactical
+
+import scala.util.parsing.syntax._
+import scala.util.parsing.combinator1.lexical.StdLexical
+
+/** This component provides primitive parsers for the standard tokens defined in `StdTokens'.
+*
+* @author Martin Odersky, Adriaan Moors
+ */
+class StandardTokenParsers extends StdTokenParsers {
+  type Tokens = StdTokens
+  val lexical = new StdLexical
+}
diff --git a/src/library/scala/util/parsing/combinator1/syntactical/StdTokenParsers.scala b/src/library/scala/util/parsing/combinator1/syntactical/StdTokenParsers.scala
new file mode 100644
index 0000000000..e344f988f8
--- /dev/null
+++ b/src/library/scala/util/parsing/combinator1/syntactical/StdTokenParsers.scala
@@ -0,0 +1,44 @@
+/*                     __                                               *\
+**     ________ ___   / /  ___     Scala API                            **
+**    / __/ __// _ | / /  / _ |    (c) 2006-2007, LAMP/EPFL             **
+**  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
+** /____/\___/_/ |_/____/_/ | |                                         **
+**                          |/                                          **
+\*                                                                      */
+
+// $Id: StdTokenParsers.scala 12242 2007-07-09 09:43:09Z michelou $
+
+
+package scala.util.parsing.combinator1.syntactical
+
+import scala.util.parsing.syntax._
+
+/** This component provides primitive parsers for the standard tokens defined in `StdTokens'.
+*
+* @author Martin Odersky, Adriaan Moors
+ */
+trait StdTokenParsers extends TokenParsers {
+  type Tokens <: StdTokens
+  import lexical.{Keyword, NumericLit, StringLit, Identifier}
+
+  /** A parser which matches a single keyword token.
+   *
+   * @param chars    The character string making up the matched keyword.
+   * @return a `Parser' that matches the given string
+   */
+  implicit def keyword(chars: String): Parser[String] = accept(Keyword(chars)) ^^ (_.chars)
+
+  /** A parser which matches a numeric literal */
+  def numericLit: Parser[String] =
+    elem("number", _.isInstanceOf[NumericLit]) ^^ (_.chars)
+
+  /** A parser which matches a string literal */
+  def stringLit: Parser[String] =
+    elem("string literal", _.isInstanceOf[StringLit]) ^^ (_.chars)
+
+  /** A parser which matches an identifier */
+  def ident: Parser[String] =
+    elem("identifier", _.isInstanceOf[Identifier]) ^^ (_.chars)
+}
+
+
diff --git a/src/library/scala/util/parsing/combinator1/syntactical/TokenParsers.scala b/src/library/scala/util/parsing/combinator1/syntactical/TokenParsers.scala
new file mode 100644
index 0000000000..d4f8a9dfc8
--- /dev/null
+++ b/src/library/scala/util/parsing/combinator1/syntactical/TokenParsers.scala
@@ -0,0 +1,64 @@
+/*                     __                                               *\
+**     ________ ___   / /  ___     Scala API                            **
+**    / __/ __// _ | / /  / _ |    (c) 2006-2007, LAMP/EPFL             **
+**  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
+** /____/\___/_/ |_/____/_/ | |                                         **
+**                          |/                                          **
+\*                                                                      */
+
+// $Id: TokenParsers.scala 12242 2007-07-09 09:43:09Z michelou $
+
+
+package scala.util.parsing.combinator1.syntactical
+
+/** <p>
+ *    This is the core component for token-based parsers.
+ *  </p>
+ *  <p>
+ *    @requires lexical a component providing the tokens consumed by the
+ *    parsers in this component.
+ *  </p>
+ *
+ *  @author Martin Odersky, Adriaan Moors
+ */
+trait TokenParsers extends Parsers {
+  /** Tokens is the abstract type of the `Token's consumed by the parsers in this component*/
+  type Tokens <: scala.util.parsing.syntax.Tokens
+
+  /** lexical is the component responsible for consuming some basic kind of
+   *  input (usually character-based) and turning it into the tokens
+   *  understood by these parsers.
+   */
+  val lexical: Tokens
+
+  /** The input-type for these parsers*/
+  type Elem = lexical.Token
+
+  /** <p>
+   *    A parser generator delimiting whole phrases (i.e. programs).
+   *  </p>
+   *  <p>
+   *    <code>phrase(p)</code> succeeds if <code>p</code> succeeds and
+   *    no input is left over after <code>p</code>.
+   *  </p>
+   *
+   *  @param p the parser that must consume all input for the resulting parser
+   *           to succeed.
+   *  @return  a parser that has the same result as `p', but that only succeeds
+   *           if <code>p</code> consumed all the input.
+   */
+  def phrase[t](p: Parser[t]) = new Parser[t] {
+    def apply(in: Input) = p(in) match {
+      case s @ Success(out, in1) if in1.atEnd => s
+      case s @ Success(out, in1) => Failure("end of input expected", in1)
+      case f @ Failure(_, in1) => in1.first match {
+        case lexical.ErrorToken(msg)  => Failure(msg, in1)
+        case lexical.EOF  => Failure("unexpected end of input", in1)
+        case t  => Failure("unexpected token "+t, in1)
+      }
+      case f => f
+    }
+  }
+}
+
+
diff --git a/src/library/scala/util/parsing/combinator1/testing/Tester.scala b/src/library/scala/util/parsing/combinator1/testing/Tester.scala
new file mode 100644
index 0000000000..e2f5d61e53
--- /dev/null
+++ b/src/library/scala/util/parsing/combinator1/testing/Tester.scala
@@ -0,0 +1,45 @@
+/*                     __                                               *\
+**     ________ ___   / /  ___     Scala API                            **
+**    / __/ __// _ | / /  / _ |    (c) 2006-2007, LAMP/EPFL             **
+**  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
+** /____/\___/_/ |_/____/_/ | |                                         **
+**                          |/                                          **
+\*                                                                      */
+
+package scala.util.parsing.combinator1.testing
+
+import scala.util.parsing.combinator1.lexical.Lexical
+import scala.util.parsing.combinator1.syntactical.TokenParsers
+
+/** <p>
+ *    Facilitates testing a given parser on various input strings.
+ *  </p>
+ *  <p>
+ *    Example use:
+ *  </p><pre>
+ *    <b>val</b> syntactic = <b>new</b> MyParsers</pre>
+ *  <p>
+ *    and
+ *  </p><pre>
+ *    <b>val</b> parser = syntactic.term</pre>
+ *  <p>
+ *    (if MyParsers extends TokenParsers with a parser called `term')
+ *  </p>
+ *
+ * @author Martin Odersky, Adriaan Moors
+ */
+abstract class Tester {
+
+  val syntactic: TokenParsers { val lexical: Lexical }
+  val parser: syntactic.Parser[Any]
+
+
+  /** Scans a String (using a `syntactic.lexical.Scanner'), parses it
+   *  using <code>phrase(parser)</code>, and  prints the input and the
+   *  parsed result to the console.
+   */
+  def test(in: String) {
+    Console.println("\nin : "+in)
+    Console.println(syntactic.phrase[Any](parser)(new syntactic.lexical.Scanner(in)))
+  }
+}