Add a visitor for Elements

sdk/lib/_internal/compiler/implementation/closure.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 closureToClassMapper;
 
 import "elements/elements.dart";
 import "dart2jslib.dart";
 import "dart_types.dart";
 import "scanner/scannerlib.dart" show Token;
 import "tree/tree.dart";
 import "util/util.dart";
 import "elements/modelx.dart" show ElementX, FunctionElementX, ClassElementX;
+import "elements/visitor.dart" show ElementVisitor;
 
 class ClosureNamer {
   String getClosureVariableName(String name, int id) {
     return "${name}_$id";
   }
 }
 
 class ClosureTask extends CompilerTask {
   Map<Node, ClosureClassMap> closureMappingCache;
   ClosureNamer namer;
@@ skipping 67 matching lines @@
   }
 
   bool isInstanceMember() => true;
   bool isAssignable() => false;
 
   DartType computeType(Compiler compiler) {
     return variableElement.computeType(compiler);
   }
 
   String toString() => "ClosureFieldElement($name)";
+
+  accept(ElementVisitor visitor) => visitor.visitClosureFieldElement(this);
 }
 
 // TODO(ahe): These classes continuously cause problems.  We need to
 // move these classes to elements/modelx.dart or see if we can find a
 // more general solution.
 class ClosureClassElement extends ClassElementX {
   DartType rawType;
   DartType thisType;
   /// Node that corresponds to this closure, used for source position.
   final FunctionExpression node;
@@ skipping 24 matching lines @@
   bool isClosure() => true;
 
   Token position() => node.getBeginToken();
 
   Node parseNode(DiagnosticListener listener) => node;
 
   /**
    * The most outer method this closure is declared into.
    */
   final Element methodElement;
+
+  accept(ElementVisitor visitor) => visitor.visitClosureClassElement(this);
 }
 
 // TODO(ahe): These classes continuously cause problems.  We need to
 // move these classes to elements/modelx.dart or see if we can find a
 // more general solution.
 class BoxElement extends ElementX {
   BoxElement(String name, Element enclosingElement)
       : super(name, ElementKind.VARIABLE_LIST, enclosingElement);
 
   DartType computeType(Compiler compiler) => compiler.types.dynamicType;
+
+  accept(ElementVisitor visitor) => visitor.visitBoxElement(this);
 }
 
 // TODO(ngeoffray, ahe): These classes continuously cause problems.  We need to
 // move these classes to elements/modelx.dart or see if we can find a
 // more general solution.
 class BoxFieldElement extends ElementX {
   BoxFieldElement(String name,
                   this.variableElement,
                   BoxElement enclosingBox)
       : super(name, ElementKind.FIELD, enclosingBox);
 
   DartType computeType(Compiler compiler) {
     return variableElement.computeType(compiler);
   }
 
   final Element variableElement;
+
+  accept(ElementVisitor visitor) => visitor.visitBoxFieldElement(this);
 }
 
 // TODO(ahe): These classes continuously cause problems.  We need to
 // move these classes to elements/modelx.dart or see if we can find a
 // more general solution.
 class ThisElement extends ElementX {
   ThisElement(Element enclosing)
       : super('this', ElementKind.PARAMETER, enclosing);
 
   bool isAssignable() => false;
 
   DartType computeType(Compiler compiler) => compiler.types.dynamicType;
 
   // Since there is no declaration corresponding to 'this', use the position of
   // the enclosing method.
   Token position() => enclosingElement.position();
+
+  accept(ElementVisitor visitor) => visitor.visitThisElement(this);
 }
 
 // TODO(ahe): These classes continuously cause problems.  We need to
 // move these classes to elements/modelx.dart or see if we can find a
 // more general solution.
 class CheckVariableElement extends ElementX {
   Element parameter;
   CheckVariableElement(String name, this.parameter, Element enclosing)
       : super(name, ElementKind.VARIABLE, enclosing);
 
   DartType computeType(Compiler compiler) => compiler.types.dynamicType;
 
   // Since there is no declaration for the synthetic 'check' variable, use
   // parameter.
   Token position() => parameter.position();
+
+  accept(ElementVisitor visitor) => visitor.visitCheckVariableElement(this);
 }
 
 // The box-element for a scope, and the captured variables that need to be
 // stored in the box.
 class ClosureScope {
   Element boxElement;
   Map<Element, Element> capturedVariableMapping;
   // If the scope is attached to a [For] contains the variables that are
   // declared in the initializer of the [For] and that need to be boxed.
   // Otherwise contains the empty List.
@@ skipping 615 matching lines @@
   }
 
   visitTryStatement(TryStatement node) {
     // TODO(ngeoffray): implement finer grain state.
     bool oldInTryStatement = inTryStatement;
     inTryStatement = true;
     node.visitChildren(this);
     inTryStatement = oldInTryStatement;
   }
 }