Changes in polymer-expressions to prepare for codegen in polymer:

pkg/polymer_expressions/lib/visitor.dart

 // 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);
 }
 
-abstract class RecursiveVisitor extends Visitor {
-  visitExpression(Expression e);
+class RecursiveVisitor extends Visitor {
+  preVisitExpression(Expression e) {}

[Siggi Cherem (dart-lang), 2014/03/21 01:43:46]

I'll use this in my codegen change.

+  visitExpression(Expression e) {}

[Siggi Cherem (dart-lang), 2014/03/21 01:43:46]

I felt I ended up overriding this for no purpose, it seemed useful to make this
class concrete and leave this empty as a default.

[Jennifer Messerly, 2014/03/21 20:08:54]

agree.

 
-  visitEmptyExpression(EmptyExpression e) => visitExpression(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) => visitExpression(l);
+  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) => visitExpression(i);
+  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);
   }
-}
+}