Add a visitor for Elements

sdk/lib/_internal/compiler/implementation/elements/visitor.dart

Index: sdk/lib/_internal/compiler/implementation/elements/visitor.dart
diff --git a/sdk/lib/_internal/compiler/implementation/elements/visitor.dart b/sdk/lib/_internal/compiler/implementation/elements/visitor.dart
new file mode 100644
index 0000000000000000000000000000000000000000..cdbe2ebfb3934c4c19e3473051e0708d7219e7ac
--- /dev/null
+++ b/sdk/lib/_internal/compiler/implementation/elements/visitor.dart
@@ -0,0 +1,89 @@
+// 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 visitor;
+
+import 'elements.dart';
+import 'modelx.dart';
+import '../scanner/scannerlib.dart'
+    show PartialClassElement;
+import '../ssa/ssa.dart'
+    show InterceptedElement;
+import '../closure.dart'
+    show ThisElement,
+         CheckVariableElement,
+         BoxElement,
+         BoxFieldElement,
+         ClosureClassElement,
+         ClosureFieldElement;
+
+abstract class ElementVisitor<R> {
+  R visit(Element e) => e.accept(this);
+
+  R visitElement(Element e);
+  R visitElementX(ElementX e) => visitElement(e);
+  R visitErroneousElement(ErroneousElement e) => visitFunctionElement(e);
+  R visitWarnOnUseElement(WarnOnUseElement e) => visitElement(e);
+  R visitAmbiguousElement(AmbiguousElement e) => visitElement(e);
+  R visitScopeContainerElement(ScopeContainerElement e) => visitElement(e);
+  R visitCompilationUnitElement(CompilationUnitElement e) => visitElement(e);
+  R visitLibraryElement(LibraryElement e) => visitScopeContainerElement(e);
+  R visitPrefixElement(PrefixElement e) => visitElement(e);
+  R visitTypedefElement(TypedefElement e) => visitElement(e);
+  R visitVariableElement(VariableElement e) => visitElement(e);
+  R visitFieldParameterElement(FieldParameterElement e) => visitElement(e);
+  R visitVariableListElement(VariableListElement e) => visitElement(e);
+  R visitAbstractFieldElement(AbstractFieldElement e) => visitElement(e);
+  R visitFunctionElement(FunctionElement e) => visitElement(e);
+  R visitConstructorBodyElement(ConstructorBodyElement e) => visitElement(e);
+  R visitClassElement(ClassElement e) => visitScopeContainerElement(e);
+  R visitTypeDeclarationElement(TypeDeclarationElement e) => visitElement(e);
+  R visitBaseClassElementX(BaseClassElementX e) => visitClassElement(e);
+  R visitClassElementX(ClassElementX e) => visitBaseClassElementX(e);

[ahe, 2013/11/29 11:44:50]

Can we find a way to avoid having X-elements in this visitor?

[sigurdm, 2013/11/29 12:29:52]

yes

+  R visitMixinApplicationElement(MixinApplicationElement e) {
+    visitClassElement(e);
+  }
+  R visitLabelElement(LabelElement e) => visitElement(e);
+  R visitTargetElement(TargetElement e) => visitElement(e);
+  R visitTypeVariableElement(TypeVariableElement e) => visitElement(e);
+  R visitErroneousElementX(ErroneousElementX e) => visitErroneousElement(e);
+  R visitWarnOnUseElementX(WarnOnUseElementX e) => visitWarnOnUseElement(e);
+  R visitAmbiguousElementX(AmbiguousElementX e) => visitAmbiguousElement(e);
+  R visitLibraryElementX(LibraryElementX e) => visitLibraryElement(e);
+  R visitPrefixElementX(PrefixElementX e) => visitPrefixElement(e);
+  R visitTypedefElementX(TypedefElementX e) => visitTypedefElement(e);
+  R visitVariableElementX(VariableElementX e) => visitVariableElement(e);
+  R visitFieldParameterElementX(FieldParameterElementX e) {
+    return visitFieldParameterElement(e);
+  }
+  R visitVariableListElementX(VariableListElementX e) {
+    return visitVariableListElement(e);
+  }
+  R visitAbstractFieldElementX(AbstractFieldElementX e) {
+    return visitAbstractFieldElement(e);
+  }
+  R visitFunctionElementX(FunctionElementX e) => visitFunctionElement(e);
+  R visitConstructorBodyElementX(ConstructorBodyElementX e) {
+    return visitFunctionElementX(e);
+  }
+  R visitSynthesizedConstructorElementX(SynthesizedConstructorElementX e) {
+    return visitFunctionElementX(e);
+  }
+  R visitVoidElementX(VoidElementX e) => visitElementX(e);
+  R visitLabelElementX(LabelElementX e) => visitLabelElement(e);
+  R visitTargetElementX(TargetElementX e) => visitTargetElement(e);
+  R visitTypeVariableElementX(TypeVariableElementX e) {
+    visitTypeVariableElement(e);
+  }
+  R visitPartialClassElement(PartialClassElement e) {
+    return visitClassElementX(e);
+  }
+  R visitInterceptedElement(InterceptedElement e) => visitElementX(e);
+  R visitThisElement(ThisElement e) => visitElementX(e);
+  R visitCheckVariableElement(CheckVariableElement e ) => visitElementX(e);
+  R visitBoxElement(BoxElement e) => visitElementX(e);
+  R visitBoxFieldElement(BoxFieldElement e) => visitElementX(e);
+  R visitClosureClassElement(ClosureClassElement e) => visitClassElementX(e);
+  R visitClosureFieldElement(ClosureFieldElement e) => visitVariableElement(e);
+}