1 files changed, 70 insertions, 0 deletions
diff --git a/src/scalap/scala/tools/scalap/rules/Result.scala b/src/scalap/scala/tools/scalap/rules/Result.scala
new file mode 100644
index 0000000000..ef4d0eb8b0
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+++ b/src/scalap/scala/tools/scalap/rules/Result.scala
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+// -----------------------------------------------------------------------------
+//
+//  Scalax - The Scala Community Library
+//  Copyright (c) 2005-8 The Scalax Project. All rights reserved.
+//
+//  The primary distribution site is http://scalax.scalaforge.org/
+//
+//  This software is released under the terms of the Revised BSD License.
+//  There is NO WARRANTY.  See the file LICENSE for the full text.
+//
+// -----------------------------------------------------------------------------
+
+package scala.tools.scalap.rules;
+
+/** Represents the combined value of two rules applied in sequence.
+ *
+ * @see the Scala parser combinator
+ */
+case class ~[+A, +B](_1 : A, _2 : B) {
+  override def toString = "(" + _1 + " ~ " + _2 + ")"
+}
+
+
+sealed abstract class Result[+Out, +A, +X] {
+  def out : Out
+  def value : A
+  def error : X
+
+  implicit def toOption : Option[A]
+
+  def map[B](f : A => B) : Result[Out, B, X]
+  def mapOut[Out2](f : Out => Out2) : Result[Out2, A, X]
+  def map[Out2, B](f : (Out, A) => (Out2, B)) : Result[Out2, B, X]
+  def flatMap[Out2, B](f : (Out, A) => Result[Out2, B, Nothing]) : Result[Out2, B, X]
+  def orElse[Out2 >: Out, B >: A](other : => Result[Out2, B, Nothing]) : Result[Out2, B, X]
+}
+
+case class Success[+Out, +A](out : Out, value : A) extends Result[Out, A, Nothing] {
+  def error = throw new ScalaSigParserError("No error")
+
+  def toOption = Some(value)
+
+  def map[B](f : A => B) : Result[Out, B, Nothing] = Success(out, f(value))
+  def mapOut[Out2](f : Out => Out2) : Result[Out2, A, Nothing] = Success(f(out), value)
+  def map[Out2, B](f : (Out, A) => (Out2, B)) : Success[Out2, B] = f(out, value) match { case (out2, b) => Success(out2, b) }
+  def flatMap[Out2, B](f : (Out, A) => Result[Out2, B, Nothing]) : Result[Out2, B, Nothing]= f(out, value)
+  def orElse[Out2 >: Out, B >: A](other : => Result[Out2, B, Nothing]) : Result[Out2, B, Nothing] = this
+}
+
+sealed abstract class NoSuccess[+X] extends Result[Nothing, Nothing, X] {
+  def out = throw new ScalaSigParserError("No output")
+  def value = throw new ScalaSigParserError("No value")
+
+  def toOption = None
+
+  def map[B](f : Nothing => B) = this
+  def mapOut[Out2](f : Nothing => Out2) = this
+  def map[Out2, B](f : (Nothing, Nothing) => (Out2, B)) = this
+  def flatMap[Out2, B](f : (Nothing, Nothing) => Result[Out2, B, Nothing]) = this
+  def orElse[Out2, B](other : => Result[Out2, B, Nothing]) = other
+}
+
+case object Failure extends NoSuccess[Nothing] {
+  def error = throw new ScalaSigParserError("No error")
+}
+
+case class ScalaSigParserError(msg: String) extends RuntimeException(msg)
+
+case class Error[+X](error : X) extends NoSuccess[X] {
+}