Add observatory_pub_packages snapshot to third_party

observatory_pub_packages/polymer_expressions/visitor.dart

Index: observatory_pub_packages/polymer_expressions/visitor.dart
===================================================================
--- observatory_pub_packages/polymer_expressions/visitor.dart	(revision 0)
+++ observatory_pub_packages/polymer_expressions/visitor.dart	(working copy)
@@ -0,0 +1,133 @@
+// Copyright (c) 2013, 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 polymer_expressions.visitor;
+
+import 'expression.dart';
+
+abstract class Visitor {
+  visit(Expression s) => s.accept(this);
+  visitEmptyExpression(EmptyExpression e);
+  visitParenthesizedExpression(ParenthesizedExpression e);
+  visitGetter(Getter i);
+  visitIndex(Index i);
+  visitInvoke(Invoke i);
+  visitLiteral(Literal l);
+  visitListLiteral(ListLiteral l);
+  visitMapLiteral(MapLiteral l);
+  visitMapLiteralEntry(MapLiteralEntry l);
+  visitIdentifier(Identifier i);
+  visitBinaryOperator(BinaryOperator o);
+  visitUnaryOperator(UnaryOperator o);
+  visitTernaryOperator(TernaryOperator o);
+  visitInExpression(InExpression c);
+  visitAsExpression(AsExpression c);
+}
+
+class RecursiveVisitor extends Visitor {
+  preVisitExpression(Expression e) {}
+  visitExpression(Expression e) {}
+
+  visitEmptyExpression(EmptyExpression e) {
+    preVisitExpression(e);
+    visitExpression(e);
+  }
+
+  visitParenthesizedExpression(ParenthesizedExpression e) {
+    preVisitExpression(e);
+    visit(e.child);
+    visitExpression(e);
+  }
+
+  visitGetter(Getter i) {
+    preVisitExpression(i);
+    visit(i.receiver);
+    visitExpression(i);
+  }
+
+  visitIndex(Index i) {
+    preVisitExpression(i);
+    visit(i.receiver);
+    visit(i.argument);
+    visitExpression(i);
+  }
+
+  visitInvoke(Invoke i) {
+    preVisitExpression(i);
+    visit(i.receiver);
+    if (i.arguments != null) {
+      for (var a in i.arguments) {
+        visit(a);
+      }
+    }
+    visitExpression(i);
+  }
+
+  visitLiteral(Literal l) {
+    preVisitExpression(l);
+    visitExpression(l);
+  }
+
+  visitListLiteral(ListLiteral l) {
+    preVisitExpression(l);
+    for (var i in l.items) {
+      visit(i);
+    }
+    visitExpression(l);
+  }
+
+  visitMapLiteral(MapLiteral l) {
+    preVisitExpression(l);
+    for (var e in l.entries) {
+      visit(e);
+    }
+    visitExpression(l);
+  }
+
+  visitMapLiteralEntry(MapLiteralEntry e) {
+    preVisitExpression(e);
+    visit(e.key);
+    visit(e.entryValue);
+    visitExpression(e);
+  }
+
+  visitIdentifier(Identifier i) {
+    preVisitExpression(i);
+    visitExpression(i);
+  }
+
+  visitBinaryOperator(BinaryOperator o) {
+    preVisitExpression(o);
+    visit(o.left);
+    visit(o.right);
+    visitExpression(o);
+  }
+
+  visitUnaryOperator(UnaryOperator o) {
+    preVisitExpression(o);
+    visit(o.child);
+    visitExpression(o);
+  }
+
+  visitTernaryOperator(TernaryOperator o) {
+    preVisitExpression(o);
+    visit(o.condition);
+    visit(o.trueExpr);
+    visit(o.falseExpr);
+    visitExpression(o);
+  }
+
+  visitInExpression(InExpression c) {
+    preVisitExpression(c);
+    visit(c.left);
+    visit(c.right);
+    visitExpression(c);
+  }
+
+  visitAsExpression(AsExpression c) {
+    visit(c.left);
+    visit(c.right);
+    visitExpression(c);
+  }
+}