Switching to the new build system and to the ne...

Switching to the new build system and to the new build system. This is a
MAJOR commit, so be careful when updating.

1 files changed, 50 insertions, 0 deletions

diff --git a/src/compiler/scala/tools/nsc/backend/WorklistAlgorithm.scala b/src/compiler/scala/tools/nsc/backend/WorklistAlgorithm.scala
new file mode 100644
index 0000000000..6676c820bc
--- /dev/null
+++ b/src/compiler/scala/tools/nsc/backend/WorklistAlgorithm.scala
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+/* NSC -- new scala compiler
+ * Copyright 2005 LAMP/EPFL
+ * @author  Martin Odersky
+ */
+
+// $Id$
+
+package scala.tools.nsc.backend;
+
+import scala.tools.nsc.ast._;
+import scala.collection.mutable.MutableList;
+
+/**
+ * Simple implementation of a worklist algorithm. A processing
+ * function is applied repeatedly to the first element in the
+ * worklist, as long as the stack is not empty.
+ *
+ * The client class should mix-in this trait and initialize the
+ * worklist field and define the processElement method. Then call
+ * the 'run' method providing a function that initializes the
+ * worklist.
+ *
+ * @see scala.tools.nsc.backend.icode.Linearizers
+ */
+trait WorklistAlgorithm {
+  type Elem;
+  type WList <: MutableList[Elem];
+
+  val worklist: WList;
+
+  /**
+   * Run the iterative algorithm until the worklist
+   * remains empty. The initializer is run once before
+   * the loop starts and should initialize the worklist.
+   */
+  def run(initWorklist: => Unit) = {
+    initWorklist;
+
+    while (!(worklist.length == 0))
+      processElement(dequeue);
+  }
+
+  /**
+   * Process the current element from the worklist.
+   */
+  def processElement(e: Elem): Unit;
+
+  /** Remove and return the first element to be processed from the worklist. */
+  def dequeue: Elem;
+}