Add date formatting and parsing code.

lib/i18n/intl.dart

Index: lib/i18n/intl.dart
===================================================================
--- lib/i18n/intl.dart	(revision 8510)
+++ lib/i18n/intl.dart	(working copy)
@@ -1,8 +1,8 @@
+// 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.
+
 /**
- * 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.
- *
  * Internationalization object providing access to message formatting objects,
  * date formatting, parsing, bidirectional text relative to a specific locale.
  */
@@ -13,7 +13,6 @@
 #import('date_format.dart');
 
 class Intl {
-
   /**
    * String indicating the locale code with which the message is to be
    * formatted (such as en-CA).
@@ -22,17 +21,46 @@
 
   IntlMessage intlMsg;
 
-  DateFormat date;
+  /**
+   * Return a new date format using the specified [pattern] or with no
+   * pattern if it was omitted. In the second case we assume that pattern
+   * will be set later, otherwise the format is not useful.

[Emily Fortuna, 2012/07/31 05:52:53]

why make pattern optional?

[Alan Knight, 2012/08/03 23:02:15]

OK, made it required.

+   * If [locale] is not specified, then we default to the locale specified

[Emily Fortuna, 2012/07/31 05:52:53]

desiredLocale

[Alan Knight, 2012/08/03 23:02:15]

Done.

+   * in this instance. Note that this is different from using the static

[Emily Fortuna, 2012/07/31 05:52:53]

"locale specified in this instance" please clarify.

[Alan Knight, 2012/08/03 23:02:15]

Done.

+   * version of this, in which case we will default to the overall default

[Emily Fortuna, 2012/07/31 05:52:53]

please rephrase this last sentence. "this" is a bit unclear unless you re-read
the sentence carefully.

[Alan Knight, 2012/08/03 23:02:15]

Moot, since I removed the static version as per a later comment.

+   * locale.
+   */
+  DateFormat date([String pattern, String desiredLocale]) {
+    var actualLocale = (desiredLocale == null) ? _locale : desiredLocale;
+    return new DateFormat(pattern,actualLocale);
+  }
 
   /**
+   * Return a new date format using the specified [pattern] or with no
+   * pattern if it was omitted. In the second case we assume that pattern
+   * will be set later, otherwise the format is not useful.
+   * If [locale] is not specified, then we use the global default locale.
+   * Note that this is different from using the instance method
+   * version of this, in which case we will default to the locale of that
+   * instance.
+   */
+  static DateFormat Date([pattern, desiredLocale]) {

[Emily Fortuna, 2012/07/31 05:52:53]

types for parameters

[Alan Knight, 2012/08/03 23:02:15]

Method removed.

+    //TODO(alanknight): I don't love the uppercase for static convention here
+    // but couldn't come up with better names, and it seems useful to be able
+    // to do this both statically and on an instance.

[Emily Fortuna, 2012/07/31 05:52:53]

if you're going to do this statically the user might as well just create a Date
object explicitly. Let's provide one way to use the Intl object, and you have to
construct the DateFormatting objects explicitly if you want to do "on the fly"
locale detection versus a specific locale.

[Alan Knight, 2012/08/03 23:02:15]

Done.

+    var actualLocale = (desiredLocale == null) ? defaultLocale: desiredLocale;
+    return new DateFormat(pattern,actualLocale);
+  }
+
+  /**
    * Constructor optionally [_locale] for specifics of the language
    * locale to be used, otherwise, we will attempt to infer it (acceptable if
    * Dart is running on the client, we can infer from the browser/client
    * preferences).
    */
-  Intl([this._locale]) {
+  Intl([locale]) {
+    _locale = locale;
     intlMsg = new IntlMessage(_locale);
-    date = new DateFormat(_locale);
   }
 
   /**
@@ -53,7 +81,24 @@
     return message_str;
   }
 
+  /** The default locale for this environment. */
+  //TODO(alanknight): Return the correct locale using either
+  // window.navigator.language or appropriate environment variable or other
+  // mechanism for command-line apps.
+  static String defaultLocale = 'en_US';
+
   /**
+   * Return the locale for this instance. If none was set, returns the
+   * default.
+   */
+  String get locale() {
+    if (_locale == null) {

[Emily Fortuna, 2012/07/31 05:52:53]

please sync your files before submitting for review. This mechanism is built
into the constructor in the current version in the repo.

+      return defaultLocale;
+    } else {
+      return _locale;}
+  }
+
+  /**
    * Support method for message formatting. Select the correct plural form from
    * [cases] given [howMany].
    */