Unify Date.fromString and support more Iso 8601.

frog/leg/lib/js_helper.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.
 
 #library('js_helper');
 
 #import('coreimpl.dart');
 
 #source('date_helper.dart');
 #source('regexp_helper.dart');
@@ skipping 1110 matching lines @@
   checkNull(receiver);
   if (receiver is !String) return UNINTERCEPTED(receiver.trim());
 
   return JS('String', @'$0.trim()', receiver);
 }
 
 class MathNatives {
   static int parseInt(str) {
     checkNull(str);
     if (str is !String) throw new IllegalArgumentException(str);
-    var trimmed = str.trim();
-    if (!JS('bool', @'/^(0[xX])?[+-]?[0-9]+$/.test($0)', trimmed)) {
+    if (!JS('bool', @'/^\s*[+-]?(0[xX])?\d+\s*$/.test($0)', str)) {
       throw new BadNumberFormatException(str);
     }
-    var ret = JS('num', @'parseInt($0, 10)', str);
+    var trimmed = str.trim();
+    var base = 10;;
+    if ((trimmed.length > 2 && (trimmed[1] == 'x' || trimmed[1] == 'X')) ||
+        (trimmed.length > 3 && (trimmed[2] == 'x' || trimmed[2] == 'X'))) {
+      base = 16;
+    }
+    var ret = JS('num', @'parseInt($0, $1)', trimmed, base);
     if (ret.isNaN()) throw new BadNumberFormatException(str);
     return ret;
   }
 
   static double parseDouble(String str) {
     checkNull(str);
     if (str is !String) throw new IllegalArgumentException();
     var ret = JS('num', @'parseFloat($0)', str);
     if (ret == 0 && (str.startsWith("0x") || str.startsWith("0X"))) {
       // TODO(ahe): This is unspecified, but tested by co19.
@@ skipping 141 matching lines @@
       }
     }
   } else if (JS('bool', @'$0 instanceof RangeError', ex)) {
     var message = JS('String', @'$0.message', ex);
     if (message.contains('call stack')) {
       return new StackOverflowException();
     }
   }
   return ex;
 }