Polish existing skeleton API.

lib/i18n/date_time_format.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.
  *
- * DateFormat is for formatting and parsing dates in a locale-sensitive 
+ * DateTimeFormat is for formatting and parsing dates in a locale-sensitive 

[Alan Knight, 2012/06/04 19:58:37]

I'd called it DateFormat because the objects it operates on are Dates, and we
don't have either Time or DateTime objects. And it's shorter.

[Emily Fortuna, 2012/06/04 22:25:57]

You're right. I'll fix it right now. 

  * manner. 
- * It allows the user to use any customized pattern to parse or format 
+ * It allows the user to choose from a set of standard date time formats as well
+ * as specify a customized pattern under certain locales. Date elements that
+ * vary across locales include month name, weekname, field, order, etc.
+ * //TODO(efortuna): Customized pattern system -- suggested by i18n needs
+ * // feedback on appropriateness.
+ * We also allow the user to use any customized pattern to parse or format 
  * date-time strings under certain locales. Date elements that vary across 
  * locales include month name, weekname, field, order, etc.
  *
  * This library uses the ICU/JDK date/time pattern specification as described
  * below.
  *
  * Time Format Syntax: To specify the time format use a time pattern string.
  * In this pattern, following letters are reserved as pattern letters, which
  * are defined in the following manner:
  *
@@ skipping 39 matching lines @@
  * instance, characters like ':', '.', ' ', '#' and '@' will appear in the
  * resulting time text even they are not embraced within single quotes. In our
  * current pattern usage, we didn't use up all letters. But those unused
  * letters are strongly discouraged to be used as quoted text without quote.
  * That's because we may use other letter for pattern in future.
  *
  * Examples Using the US Locale:
  *
  *     Format Pattern                         Result
  *     --------------                         -------
- *     "yyyy.MM.dd G 'at' HH:mm:ss vvvv"->> 1996.07.10 AD at 15:08:56 Pacific Time
- *     "EEE, MMM d, ''yy"               ->> Wed, July 10, '96
- *     "h:mm a"                         ->> 12:08 PM
- *     "hh 'o''clock' a, zzzz"          ->> 12 o'clock PM, Pacific Daylight Time
- *     "K:mm a, vvv"                    ->> 0:00 PM, PT
- *     "yyyyy.MMMMM.dd GGG hh:mm aaa"   ->> 01996.July.10 AD 12:08 PM
+ *     "yyyy.MM.dd G 'at' HH:mm:ss vvvv"->1996.07.10 AD at 15:08:56 Pacific Time
+ *     "EEE, MMM d, ''yy"               ->Wed, July 10, '96
+ *     "h:mm a"                         ->12:08 PM
+ *     "hh 'o''clock' a, zzzz"          ->12 o'clock PM, Pacific Daylight Time
+ *     "K:mm a, vvv"                    ->0:00 PM, PT
+ *     "yyyyy.MMMMM.dd GGG hh:mm aaa"   ->01996.July.10 AD 12:08 PM
  *
  * When parsing a date string using the abbreviated year pattern ("yy"),
  * DateTimeParse must interpret the abbreviated year relative to some
  * century. It does this by adjusting dates to be within 80 years before and 20
  * years after the time the parse function is called. For example, using a
  * pattern of "MM/dd/yy" and a DateTimeParse instance created on Jan 1, 1997,
  * the string "01/11/12" would be interpreted as Jan 11, 2012 while the string
  * "05/04/64" would be interpreted as May 4, 1964. During parsing, only
  * strings consisting of exactly two digits, as defined by {@link
  * java.lang.Character#isDigit(char)}, will be parsed into the default
  * century. Any other numeric string, such as a one digit string, a three or
  * more digit string will be interpreted as its face value.
  *
  * If the year pattern does not have exactly two 'y' characters, the year is
  * interpreted literally, regardless of the number of digits. So using the
  * pattern "MM/dd/yyyy", "01/11/12" parses to Jan 11, 12 A.D.
  *
  * When numeric fields abut one another directly, with no intervening
  * delimiter characters, they constitute a run of abutting numeric fields. Such
  * runs are parsed specially. For example, the format "HHmmss" parses the input
  * text "123456" to 12:34:56, parses the input text "12345" to 1:23:45, and
  * fails to parse "1234". In other words, the leftmost field of the run is
  * flexible, while the others keep a fixed width. If the parse fails anywhere in
  * the run, then the leftmost field is shortened by one character, and the
  * entire run is parsed again. This is repeated until either the parse succeeds
  * or the leftmost field is one character in length. If the parse still fails at
  * that point, the parse of the run fails.
  */
 
-#library('DateFormat');
+#library('DateTimeFormat');
 
-class DateFormat {
+class DateTimeFormat {
 
   /** Definition of this object formats dates. */
   var formatDefinition;
 
-   /** Date/Time format patterns. */
-   // TODO(alanknight): There's a style question of whether to use fullDate or 
-   // FULL_DATE naming conventions.
-   static final int _fullDate = 0;
-   static final int _longDate = 1;
-   static final int _mediumDate = 2;
-   static final int _shortDate = 3;
-   static final int _fullTime = 4;
-   static final int _longTime = 5;
-   static final int _mediumTime = 6;
-   static final int _shortTime = 7;
-   static final int _fullDateTime = 8;
-   static final int _longDateTime = 9;
-   static final int _mediumDateTime = 10;
-   static final int _shortDateTime = 11;
+  /**
+   * String indicating a language code with which the message is to be

[Alan Knight, 2012/06/04 19:58:37]

Strictly I think language would be just the "en" part, and en-US would be a
locale code.

[Emily Fortuna, 2012/06/04 22:25:57]

Done.

+   * formatted (such as en-US).
+   */
+  String _locale;
+
+  /** 
+   * Date/Time format "skeleton" patterns. Also specifiable by String, but
+   * written this way so that they can be discoverable via autocomplete.

[Alan Knight, 2012/06/04 19:58:37]

We should probably say where these come from and/or indicate what the characters
mean. While most are obvious, some are less so, e.g. L, E. Maybe even examples
would be good for the non-i18n literate.

[Emily Fortuna, 2012/06/04 22:25:57]

Done.

+   */
+  static final String Hm = 'Hm';          // HH:mm

[Alan Knight, 2012/06/04 19:58:37]

So usage on these is, e.g.
   new DateTimeFormat(DateTimeFormat.Hms);
?
Are people going to want to type that instead of using the string literal? Is
the case significant on these? Seems like it probably is, but discoverability
would probably be better if all lowercase. But maybe autocomplete doesn't care.
Would named constructors for these be better? Or methods on Intl? e.g.
   new DateTimeFormat.Hms()
or 
   Intl.dateHms();

[Emily Fortuna, 2012/06/04 22:25:57]

Realistically, no, people are not going to want to type that. They're provided
more to be discovered than for extensive use... see page 4 on my User Guide --
they can also be called as intl.date.Hms. I can provide named constructors for
these (in addition??) if that would be better (seems like it would).

+  static final String Hms = 'Hms';        // HH:mm:ss 
+  static final String M = 'M';            // L
+  static final String MEd = 'MEd';        // E, M/d
+  static final String MMM = 'MMM';        // LLL
+  static final String MMMEd = 'MMMEd';    // E, MMM d
+  static final String MMMMEd = 'MMMMEd';  // E, MMMM d
+  static final String MMMMd = 'MMMMd';    // MMMM d
+  static final String MMMd = 'MMMd';      // MMM d
+  static final String Md = 'Md';          // M/d
+  static final String d = 'd';            // d
+  static final String hm = 'hm';          // h:mm a
+  static final String ms = 'ms';          // mm:ss
+  static final String y = 'y';            // yyyy
+  static final String yM = 'yM';          // M/yyyy
+  static final String yMEd = 'yMEd';      // EEE, M/d/yyyy
+  static final String yMMM = 'yMMM';      // MMM yyyy
+  static final String yMMMEd = 'yMMMEd';  // EEE, MM d, yyyy
+  static final String yMMMM = 'yMMMM';    // MMMM yyyy
+  static final String yQ = 'yQ';          // Q yyyy
+  static final String yQQQ = 'yQQQ';      // QQQ yyyy
+
+  /** Date/Time format patterns. */

[Alan Knight, 2012/06/04 19:58:37]

We should probably make this mechanism more consistent with the skeletons.

[Emily Fortuna, 2012/06/04 22:25:57]

Fixing...

+  // TODO(alanknight): There's a style question of whether to use fullDate or 
+  // FULL_DATE naming conventions.
+  static final int _fullDate = 0;
+  static final int _longDate = 1;
+  static final int _mediumDate = 2;
+  static final int _shortDate = 3;
+  static final int _fullTime = 4;
+  static final int _longTime = 5;
+  static final int _mediumTime = 6;
+  static final int _shortTime = 7;
+  static final int _fullDateTime = 8;
+  static final int _longDateTime = 9;
+  static final int _mediumDateTime = 10;
+  static final int _shortDateTime = 11;
     
   /**
    * Named constructors for each of the above values.
    * These could probably be made shorter if we just set the format to the 
    * constant and the parsing was lazy.
    */
-  DateFormat.fullDate() : this.formatDefinition = _fullDate;
-  DateFormat.longDate() : this.formatDefinition = _longDate;
-  DateFormat.mediumDate() : this.formatDefinition = _mediumDate;
-  DateFormat.shortDate() : this.formatDefinition = _shortDate;
-  DateFormat.fullTime() : this.formatDefinition = _fullTime;
-  DateFormat.longTime() : this.formatDefinition = _longTime;
-  DateFormat.mediumTime() : this.formatDefinition = _mediumTime;
-  DateFormat.shortTime() : this.formatDefinition = _shortTime;
-  DateFormat.fullDateTime() : this.formatDefinition = _fullDateTime;
-  DateFormat.longDateTime() : this.formatDefinition = _longDateTime;
-  DateFormat.mediumDateTime() : this.formatDefinition = _mediumDateTime;
-  DateFormat.shortDateTime() : this.formatDefinition = _shortDateTime;
+  DateTimeFormat.fullDate() : this.formatDefinition = _fullDate;
+  DateTimeFormat.longDate() : this.formatDefinition = _longDate;
+  DateTimeFormat.mediumDate() : this.formatDefinition = _mediumDate;
+  DateTimeFormat.shortDate() : this.formatDefinition = _shortDate;
+  DateTimeFormat.fullTime() : this.formatDefinition = _fullTime;
+  DateTimeFormat.longTime() : this.formatDefinition = _longTime;
+  DateTimeFormat.mediumTime() : this.formatDefinition = _mediumTime;
+  DateTimeFormat.shortTime() : this.formatDefinition = _shortTime;
+  DateTimeFormat.fullDateTime() : this.formatDefinition = _fullDateTime;
+  DateTimeFormat.longDateTime() : this.formatDefinition = _longDateTime;
+  DateTimeFormat.mediumDateTime() : this.formatDefinition = _mediumDateTime;
+  DateTimeFormat.shortDateTime() : this.formatDefinition = _shortDateTime;
   
-  DateFormat(this.formatDefinition);
+  /**
+   * Constructor accepts a [formatDefinition], which can be a String, one of the
+   * predefined static forms, or a custom date format using the syntax described
+   * above. An optional [_locale] can be provided 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).
+   */
+  DateTimeFormat(this.formatDefinition, [this._locale]);
 
   /**
-   * 
+   * Given user input, attempt to parse the [inputString] into the anticipated
+   * format.
    */
   String parse(String inputString) {
     return inputString;
   }
 
  /**
   * Format the given [date] object according to preset pattern and current 
   * locale and return a formated string for the given date.
   */
   String format(Date date, [TimeZone timeZone]) {
     // TODO(efortuna): optional TimeZone argument? TimeZone is deprecated...
     return date.toString();
   }
 }