improve DateTime parsing a UTC timezone offset

sdk/lib/core/date_time.dart

Index: sdk/lib/core/date_time.dart
diff --git a/sdk/lib/core/date_time.dart b/sdk/lib/core/date_time.dart
index 0b4a63a19a0c63eb8fe2baa877c109c800b595a6..566260607c1c566f0670e58e90bc2377bde162a3 100644
--- a/sdk/lib/core/date_time.dart
+++ b/sdk/lib/core/date_time.dart
@@ -48,7 +48,7 @@ part of dart.core;
  * unless explicitly created in the UTC time zone.
  *
  *     DateTime dDay = new DateTime.utc(1944, 6, 6);
- *    
+ *
  * Use [isUtc] to determine whether a DateTime object is based in UTC.
  * Use the methods [toLocal] and [toUtc]
  * to get the equivalent date/time value specified in the other time zone.
@@ -199,13 +199,14 @@ class DateTime implements Comparable {
    * * `"20120227"`
    * * `"+20120227"`
    * * `"2012-02-27T14Z"`
+   * * `"2012-02-27T14+00:00"`
    * * `"-123450101 00:00:00 Z"`: in the year -12345.
    */
   // TODO(floitsch): specify grammar.
   static DateTime parse(String formattedString) {
     final RegExp re = new RegExp(
         r'^([+-]?\d?\d\d\d\d)-?(\d\d)-?(\d\d)'  // The day part.
-        r'(?:[ T](\d\d)(?::?(\d\d)(?::?(\d\d)(.\d{1,6})?)?)? ?([zZ])?)?$');
+        r'(?:[ T](\d\d)(?::?(\d\d)(?::?(\d\d)(.\d{1,6})?)?)? ?([zZ]|(\+00(:?00)?)?))?$');

[floitsch, 2013/10/28 23:01:24]

80 chars.
The "(\+00" should be a non-capturing ("(:?").

     Match match = re.firstMatch(formattedString);
     if (match != null) {
       int parseIntOrZero(String matched) {