Implement JSON serialization to stream.

lib/json/json.dart

 // Copyright (c) 2011, 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("json");
 
 // Pure Dart implementation of JSON protocol.
 
 /**
  * Utility class to parse JSON and serialize objects to JSON.
@@ skipping 14 matching lines @@
   static int length(String str) {
     return _JsonParser.objectLength(str);
   }
 
   /**
    * Serializes [:object:] into JSON string.
    */
   static String stringify(Object object) {
     return JsonStringifier.stringify(object);
   }
+
+  /**
+   * Serializes [:object:] into [:output:] stream.

[Søren Gjesse, 2012/06/25 07:46:38]

DBC

Shouldn this be just [object] and [output] (without the :'s) when referring to
the arguments?

[podivilov, 2012/06/25 13:28:44]

grep showed that it probably should. Do you know if this syntax is documented
somewhere?

[ahe, 2012/06/25 13:30:22]

Sorry, Google-internal URL:

http://chromegw.corp.google.com/viewvc/dash/attic/guide/dartguide.xml#Comment...

+   */
+  static void printOn(Object object, StringBuffer output) {
+    return JsonStringifier.printOn(object, output);
+  }
 }
 
 //// Implementation ///////////////////////////////////////////////////////////
 
 // TODO(ajohnsen): Introduce when we have a common exception interface for json.
 class JSONParseException {
   JSONParseException(int position, String message) :
       position = position,
       message = 'JSONParseException: $message, at offset $position';
 
@@ skipping 349 matching lines @@
   static List<int> tokens;
 }
 
 // TODO: proper base class.
 class JsonUnsupportedObjectType {
   const JsonUnsupportedObjectType();
 }
 
 class JsonStringifier {
   static String stringify(final object) {
-    JsonStringifier stringifier = new JsonStringifier._internal();
+    StringBuffer output = new StringBuffer();
+    JsonStringifier stringifier = new JsonStringifier._internal(output);
     stringifier._stringify(object);
-    return stringifier._result;
+    return output.toString();
   }
 
-  JsonStringifier._internal()
-      : _sb = new StringBuffer(), _seen = new List<Object>() {}
+  static void printOn(final object, StringBuffer output) {
+    JsonStringifier stringifier = new JsonStringifier._internal(output);
+    stringifier._stringify(object);
+  }
+
+  JsonStringifier._internal(this._sb)
+      : _seen = [];
+
   StringBuffer _sb;
   List<Object> _seen;  // TODO: that should be identity set.
-  String get _result() { return _sb.toString(); }
 
   static String _numberToString(num x) {
     // TODO: need some more investigation what to do with precision
     // of double values.
     if (x is int) {
       return x.toString();
     } else if (x is double) {
       return x.toString();
     } else {
       return x.toDouble().toString();
@@ skipping 109 matching lines @@
         first = false;
       });
       _sb.add('}');
       _seen.removeLast();
       return;
     } else {
       throw const JsonUnsupportedObjectType();
     }
   }
 }