Polish Date formatting API.

lib/i18n/date_format.dart

Index: lib/i18n/date_format.dart
===================================================================
--- lib/i18n/date_format.dart	(revision 8135)
+++ lib/i18n/date_format.dart	(working copy)
@@ -5,11 +5,13 @@
  *
  * DateFormat is for formatting and parsing dates in a locale-sensitive 
  * manner. 
- * It allows 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.
+ * 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 -- needs feedback on
+ * // appropriateness.
  *
- * This library uses the ICU/JDK date/time pattern specification as described
+ * This library uses the ICU date/time pattern specification as described
  * below.
  *
  * Time Format Syntax: To specify the time format use a time pattern string.
@@ -19,7 +21,7 @@
  *     Symbol   Meaning                Presentation        Example
  *     ------   -------                ------------        -------
  *     G        era designator         (Text)              AD
- *     y#       year                   (Number)            1996
+ *     y        year                   (Number)            1996
  *     M        month in year          (Text & Number)     July & 07
  *     d        day in month           (Number)            10
  *     h        hour in am/pm (1~12)   (Number)            12
@@ -35,11 +37,7 @@
  *     z        time zone              (Text)              Pacific Standard Time
  *     Z        time zone (RFC 822)    (Number)            -0800
  *     v        time zone (generic)    (Text)              Pacific Time
- *     '        escape for text        (Delimiter)         'Date='
- *     ''       single quote           (Literal)           'o''clock'
  *
- * Items marked with '#' work differently than in Java.
- *
  * The count of pattern letters determine the format.
  * (Text): 4 or more pattern letters--use full form,
  *         less than 4--use short or abbreviated form if one exists.
@@ -65,12 +63,12 @@
  *
  *     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
@@ -100,49 +98,49 @@
  * that point, the parse of the run fails.
  */
 
-#library('DateFormat');
+#library('DateTimeFormat');

[Alan Knight, 2012/06/03 17:19:52]

I had deliberately called it DateFormat, rather than DateTimeFormat, on the
basis that the things it operates on are of class Date, and we don't have Time
or DateTime.

 
-class DateFormat {
+class DateTimeFormat {
 
   /** Definition of this object formats dates. */
-  var formatDefinition;
+  String 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;
-    
-  /**
-   * 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.
+  /** 
+   * Date/Time format patterns. Also specifiable by String, but written this way
+   * so that they can be discoverable via autocomplete.
    */
-  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;
-  
-  DateFormat(this.formatDefinition);
+  static final String Hm = 'Hm';          // HH:mm
+  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
+    
 
+  DateTimeFormat(this.formatDefinition, [this._locale]) {

[Alan Knight, 2012/06/03 17:19:52]

Should we allow formatDefinition to also be optional so you can just ask for a
new instance with a default format? Or would that then force people to use names
on the arguments? It might be that that use case is supported once we have the
Intl object and they can just ask for a default instance that way.

+    default_forms = ['Hm', 'Hms', 'M', 'MEd', 'MMM', 'MMMEd', 'MMMMEd', 'MMMMd',
+                     'MMMd', 'Md', 'd', 'hm', 'ms', 'y', 'yM', 'yMEd', 'yMMM',
+                     'yMMMEd', 'yMMMM', 'yQ', 'yQQQ'];
+    // Default to full date and time if it does not match one of our expected
+    // forms (for now).
+    if(!default_forms.contains(formatDefinition)) formatDefinition = 'yMMMEd';
+  }
+
   /**
    * 
    */
@@ -154,7 +152,7 @@
   * 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]) {
+  String format(Date date) {
     // TODO(efortuna): optional TimeZone argument? TimeZone is deprecated...
     return date.toString();
   }