PrettyPrinter: add an ability to prefix node fields, so instead of:

lib/compiler/implementation/tree/prettyprint.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.
 
 /**
  * Pretty-prints Node tree in XML-like format.
  *
  * TODO(smok): Add main() to run from command-line to print out tree for given
  * .dart file.
  */
 class PrettyPrinter implements Visitor {
 
   /** String used to represent one level of indent. */
   static final String INDENT = "  ";
 
   StringBuffer sb;
   int depth;
+  /** Prefix for the type passed to the next [openNode()] call. */
+  String nextTypePrefix;
 
   PrettyPrinter() : sb = new StringBuffer(), depth = 0;
 
   /**
    * Adds given string to result string.
    */
   void add(SourceString string) {
     string.printOn(sb);
   }
 
@@ skipping 26 matching lines @@
    */
   void closeNode(String type, [Map params]) {
     depth--;
     addCurrentIndent();
     sb.add("</");
     addTypeWithParams(type, params);
     sb.add(">\n");
   }
 
   void addTypeWithParams(String type, [Map params]) {
+    if (nextTypePrefix !== null) {
+      sb.add(nextTypePrefix);
+      nextTypePrefix = null;
+    }
     sb.add("${type}");
     if (params != null) {
       // TODO(smok): Escape doublequotes in values.
       params.forEach((k, v) => sb.add(' $k="$v"'));
     }
   }
 
   void addCurrentIndent() {
     for (int i = 0; i < depth; i++) {
       sb.add(INDENT);
@@ skipping 161 matching lines @@
   }
 
   visitReturn(Return node) {
     visitNodeWithChildren(node, "Return");
   }
 
   visitScriptTag(ScriptTag node) {
     visitNodeWithChildren(node, "ScriptTag");
   }
 
+  /** Custom helper to visit given node and print its type with prefix. */
+  visitWithPrefix(Node node, String prefix) {
+    nextTypePrefix = prefix;
+    node.accept(this);
+  }
+
+  openSendNodeWithFields(Send node, String type) {
+    openNode(type, {
+        "isPrefix" : "${node.isPrefix}",
+        "isPostfix" : "${node.isPostfix}",
+        "isIndex" : "${node.isIndex}"
+    });
+    if (node.receiver !== null) visitWithPrefix(node.receiver, "receiver:");
+    if (node.selector !== null) visitWithPrefix(node.selector, "selector:");
+    if (node.argumentsNode !== null)
+        visitWithPrefix(node.argumentsNode, "argumentsNode:");
+  }
+
   visitSend(Send node) {
-    visitNodeWithChildren(node, "Send");
+    openSendNodeWithFields(node, "Send");
+    closeNode("Send");
   }
 
   visitSendSet(SendSet node) {
-    visitNodeWithChildren(node, "SendSet");
+    openSendNodeWithFields(node, "SendSet");
+    if (node.assignmentOperator !== null)
+        visitWithPrefix(node.assignmentOperator, "assignmentOperator:");
+    closeNode("SendSet");
   }
 
   visitStringInterpolation(StringInterpolation node) {
     visitNodeWithChildren(node, "StringInterpolation");
   }
 
   visitStringInterpolationPart(StringInterpolationPart node) {
     visitNodeWithChildren(node, "StringInterpolationPart");
   }
 
@@ skipping 30 matching lines @@
   }
 
   visitVariableDefinitions(VariableDefinitions node) {
     visitNodeWithChildren(node, "VariableDefinitions");
   }
 
   visitWhile(While node) {
     visitNodeWithChildren(node, "While");
   }
 }