Switch-implementation.

frog/leg/elements/elements.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #library('elements');
 
 #import('../tree/tree.dart');
 #import('../scanner/scannerlib.dart');
 #import('../leg.dart');  // TODO(karlklose): we only need type.
 #import('../util/util.dart');
@@ skipping 829 matching lines @@
     isBreakTarget = true;
     target.isBreakTarget = true;
   }
   void setContinueTarget() {
     isContinueTarget = true;
     target.isContinueTarget = true;
   }
 
   bool get isTarget() => isBreakTarget || isContinueTarget;
   Node parseNode(DiagnosticListener l) => label;
+
+  Token position() => label.token;
+  String toString() => "${labelName}:";
 }
 
 // Represents a reference to a statement, either a label or the
 // default target of a break or continue.
 class StatementElement extends Element {
   final Statement statement;
+  final int nestingLevel;
   Link<LabelElement> labels = const EmptyLink<LabelElement>();
   bool isBreakTarget = false;
   bool isContinueTarget = false;
 
-  StatementElement(this.statement, Element enclosingElement)
+  StatementElement(this.statement, this.nestingLevel, Element enclosingElement)
       : super(const SourceString(""), ElementKind.STATEMENT, enclosingElement);
   bool get isTarget() => isBreakTarget || isContinueTarget;
 
   LabelElement addLabel(Identifier label, String labelName) {
     LabelElement result = new LabelElement(label, labelName, this,
                                            enclosingElement);
     labels = labels.prepend(result);
     return result;
   }
 
   Node parseNode(DiagnosticListener l) => statement;
+
+  String implicitLabel() =>
+      (statement is SwitchStatement) ? '\$$nestingLevel' : null;
+
+  Token position() => statement.getBeginToken();
+  String toString() => statement.toString();
 }