Start moving non-platform libraries from lib/ to pkg/ .

lib/i18n/date_format.dart

Index: lib/i18n/date_format.dart
===================================================================
--- lib/i18n/date_format.dart	(revision 10654)
+++ lib/i18n/date_format.dart	(working copy)
@@ -1,530 +0,0 @@
-// 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
- * manner.
- * 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, week name, 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 both for
- * complete format specifications and also the abbreviated "skeleton" form
- * which can also adapt to different locales and is preferred where available.
- *
- * Skeletons: These can be specified either as the ICU constant name or as the
- * skeleton to which it resolves. The supported set of skeletons is as follows
- *   ICU Name                   Skeleton
- *   --------                   --------
- *   DAY                          d
- *   ABBR_WEEKDAY                 E
- *   WEEKDAY                      EEEE
- *   ABBR_STANDALONE_MONTH        LLL
- *   STANDALONE_MONTH             LLLL
- *   NUM_MONTH                    M
- *   NUM_MONTH_DAY                Md
- *   NUM_MONTH_WEEKDAY_DAY        MEd
- *   ABBR_MONTH                   MMM
- *   ABBR_MONTH_DAY               MMMd
- *   ABBR_MONTH_WEEKDAY_DAY       MMMEd
- *   MONTH                        MMMM
- *   MONTH_DAY                    MMMMd
- *   MONTH_WEEKDAY_DAY            MMMMEEEEd
- *   ABBR_QUARTER                 QQQ
- *   QUARTER                      QQQQ
- *   YEAR                         y
- *   YEAR_NUM_MONTH               yM
- *   YEAR_NUM_MONTH_DAY           yMd
- *   YEAR_NUM_MONTH_WEEKDAY_DAY   yMEd
- *   YEAR_ABBR_MONTH              yMMM
- *   YEAR_ABBR_MONTH_DAY          yMMMd
- *   YEAR_ABBR_MONTH_WEEKDAY_DAY  yMMMEd
- *   YEAR_MONTH                   yMMMM
- *   YEAR_MONTH_DAY               yMMMMd
- *   YEAR_MONTH_WEEKDAY_DAY       yMMMMEEEEd
- *   YEAR_ABBR_QUARTER            yQQQ
- *   YEAR_QUARTER                 yQQQQ
- *   HOUR24                       H
- *   HOUR24_MINUTE                Hm
- *   HOUR24_MINUTE_SECOND         Hms
- *   HOUR                         j
- *   HOUR_MINUTE                  jm
- *   HOUR_MINUTE_SECOND           jms
- *   HOUR_MINUTE_GENERIC_TZ       jmv
- *   HOUR_MINUTE_TZ               jmz
- *   HOUR_GENERIC_TZ              jv
- *   HOUR_TZ                      jz
- *   MINUTE                       m
- *   MINUTE_SECOND                ms
- *   SECOND                       s
- *
- * Examples Using the US Locale:
- *
- *     Pattern                           Result
- *     ----------------                  -------
- *     "yMd"                            -> 07/10/1996
- *     "yMMMMd"                         -> July 10, 1996
- *     "Hm"                             -> 12:08 PM
- *
- * Explicit Pattern Syntax: Formats can also be specified with a pattern string.
- * The skeleton forms will resolve to explicit patterns of this form, but will
- * also adapt to different patterns in different locales.
- * The following characters are reserved:
- *
- *     Symbol   Meaning                Presentation        Example
- *     ------   -------                ------------        -------
- *     G        era designator         (Text)              AD
- *     y        year                   (Number)            1996
- *     M        month in year          (Text & Number)     July & 07
- *     L        standalone month       (Text & Number)     July & 07
- *     d        day in month           (Number)            10
- *     c        standalone day         (Number)            10
- *     h        hour in am/pm (1~12)   (Number)            12
- *     H        hour in day (0~23)     (Number)            0
- *     m        minute in hour         (Number)            30
- *     s        second in minute       (Number)            55
- *     S        fractional second      (Number)            978
- *     E        day of week            (Text)              Tuesday
- *     D        day in year            (Number)            189
- *     a        am/pm marker           (Text)              PM
- *     k        hour in day (1~24)     (Number)            24
- *     K        hour in am/pm (0~11)   (Number)            0
- *     z        time zone              (Text)              Pacific Standard Time
- *     Z        time zone (RFC 822)    (Number)            -0800
- *     v        time zone (generic)    (Text)              Pacific Time
- *     Q        quarter                (Text)              Q3
- *     '        escape for text        (Delimiter)         'Date='
- *     ''       single quote           (Literal)           'o''clock'
- *
- * The count of pattern letters determine the format.
- * **Text**:
- * * 5 pattern letters--use narrow form for standalone. Otherwise does not apply
- * * 4 or more pattern letters--use full form,
- * * 3 pattern letters--use short or abbreviated form if one exists
- * * less than 3--use numeric form if one exists
- *
- * **Number**: the minimum number of digits. Shorter numbers are zero-padded to
- * this amount (e.g. if "m" produces "6", "mm" produces "06"). Year is handled
- * specially; that is, if the count of 'y' is 2, the Year will be truncated to
- * 2 digits. (e.g., if "yyyy" produces "1997", "yy" produces "97".) Unlike other
- * fields, fractional seconds are padded on the right with zero.
- *
- * (Text & Number): 3 or over, use text, otherwise use number.
- *
- * Any characters that not in the pattern will be treated as quoted text. For
- * 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
- *
- * When parsing a date string using the abbreviated year pattern ("yy"),
- * DateFormat 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('date_format');
-
-#import('intl.dart');
-#import('date_time_patterns.dart');
-#import('date_symbols.dart');
-#import('date_symbol_data.dart');
-
-#source('lib/date_format_field.dart');
-#source('lib/date_format_helpers.dart');
-
-class DateFormat {
-
-  /**
-   * If [newPattern] matches one of the skeleton forms, it is looked up
-   * in [locale] or in the default if none is specified, and the corresponding
-   * full format string is used. If [newPattern] does not match one
-   * of the supported skeleton forms then it is used as a format directly.
-   *
-   * For example, in an en_US locale, specifying the skeleton
-   *     `new DateFormat('yMEd');`
-   * or the explicit
-   *     `new DateFormat('EEE, M/d/y');`
-   * would produce the same result, a date of the form
-   *     `Wed, 6/27/2012`
-   * However, the skeleton version would also adapt to other locales.
-   *
-   * If [locale] does not exist in our set of supported locales then an
-   * [IllegalArgumentException] is thrown.
-   */
-  DateFormat([String newPattern, String locale]) {
-    // TODO(alanknight): It should be possible to specify multiple skeletons eg
-    // date, time, timezone all separately. Adding many or named parameters to
-    // the constructor seems awkward, especially with the possibility of
-    // confusion with the locale. A "fluent" interface with cascading on an
-    // instance might work better? A list of patterns is also possible.
-    // TODO(alanknight): There will need to be at least setup type async
-    // operations to avoid the need to bring along every locale in every program
-    _locale = Intl.verifiedLocale(locale);
-    _setPattern(newPattern);
-  }
-
-  /**
-   * Return a string representing [date] formatted according to our locale
-   * and internal format.
-   */
-  String format(Date date) {
-    // TODO(efortuna): read optional TimeZone argument (or similar)?
-    var result = new StringBuffer();
-    _formatFields.forEach((field) => result.add(field.format(date)));
-    return result.toString();
-  }
-
-  /**
-   * Returns a date string indicating how long ago (3 hours, 2 minutes)
-   * something has happened or how long in the future something will happen
-   * given a [reference] Date relative to the current time.
-   */
-  String formatDuration(Date reference) {
-    return '';
-  }
-
-  /**
-   * Formats a string indicating how long ago (negative [duration]) or how far
-   * in the future (positive [duration]) some time is with respect to a
-   * reference [date].
-   */
-  String formatDurationFrom(Duration duration, Date date) {
-    return '';
-  }
-
-  /**
-   * Given user input, attempt to parse the [inputString] into the anticipated
-   * format, treating it as being in the local timezone.
-   */
-  Date parse(String inputString, [utc = false]) {
-    var dateFields = new _DateBuilder();
-    if (utc) dateFields.utc=true;
-    var stream = new _Stream(inputString);
-    _formatFields.forEach(
-        (each) => each.parse(stream, dateFields));
-    return dateFields.asDate();
-  }
-
-  /**
-   * Given user input, attempt to parse the [inputString] into the anticipated
-   * format, treating it as being in UTC.
-   */
-  Date parseUTC(String inputString) {
-    return parse(inputString, true);
-  }
-
-  /**
-   * Return the locale code in which we operate, e.g. 'en_US' or 'pt'.
-   */
-  String get locale() => _locale;
-
-  /**
-   * Constructors for a set of predefined formats for which
-   * internationalized forms are known. These can be specified
-   * either as ICU constants, or as skeletons.
-   */
-  DateFormat.DAY([locale]) : this(DAY, locale);
-  DateFormat.ABBR_WEEKDAY([locale]) : this(ABBR_WEEKDAY, locale);
-  DateFormat.WEEKDAY([locale]) : this(WEEKDAY, locale);
-  DateFormat.ABBR_STANDALONE_MONTH([locale]) :
-      this(ABBR_STANDALONE_MONTH, locale);
-  DateFormat.STANDALONE_MONTH([locale]) : this(STANDALONE_MONTH, locale);
-  DateFormat.NUM_MONTH([locale]) : this(NUM_MONTH, locale);
-  DateFormat.NUM_MONTH_DAY([locale]) : this(NUM_MONTH_DAY, locale);
-  DateFormat.NUM_MONTH_WEEKDAY_DAY([locale]) :
-      this(NUM_MONTH_WEEKDAY_DAY, locale);
-  DateFormat.ABBR_MONTH([locale]) : this(ABBR_MONTH, locale);
-  DateFormat.ABBR_MONTH_DAY([locale]) : this(ABBR_MONTH_DAY, locale);
-  DateFormat.ABBR_MONTH_WEEKDAY_DAY([locale]) :
-      this(ABBR_MONTH_WEEKDAY_DAY, locale);
-  DateFormat.MONTH([locale]) : this(MONTH, locale);
-  DateFormat.MONTH_DAY([locale]) : this(MONTH_DAY, locale);
-  DateFormat.MONTH_WEEKDAY_DAY([locale]) : this(MONTH_WEEKDAY_DAY, locale);
-  DateFormat.ABBR_QUARTER([locale]) : this(ABBR_QUARTER, locale);
-  DateFormat.QUARTER([locale]) : this(QUARTER, locale);
-  DateFormat.YEAR([locale]) : this(YEAR, locale);
-  DateFormat.YEAR_NUM_MONTH([locale]) : this(YEAR_NUM_MONTH, locale);
-  DateFormat.YEAR_NUM_MONTH_DAY([locale]) : this(YEAR_NUM_MONTH_DAY, locale);
-  DateFormat.YEAR_NUM_MONTH_WEEKDAY_DAY([locale]) :
-      this(YEAR_NUM_MONTH_WEEKDAY_DAY, locale);
-  DateFormat.YEAR_ABBR_MONTH([locale]) : this(YEAR_ABBR_MONTH, locale);
-  DateFormat.YEAR_ABBR_MONTH_DAY([locale]) : this(YEAR_ABBR_MONTH_DAY, locale);
-  DateFormat.YEAR_ABBR_MONTH_WEEKDAY_DAY([locale]) :
-      this(YEAR_ABBR_MONTH_WEEKDAY_DAY, locale);
-  DateFormat.YEAR_MONTH([locale]) : this(YEAR_MONTH, locale);
-  DateFormat.YEAR_MONTH_DAY([locale]) : this(YEAR_MONTH_DAY, locale);
-  DateFormat.YEAR_MONTH_WEEKDAY_DAY([locale]) :
-      this(YEAR_MONTH_WEEKDAY_DAY, locale);
-  DateFormat.YEAR_ABBR_QUARTER([locale]) : this(YEAR_ABBR_QUARTER, locale);
-  DateFormat.YEAR_QUARTER([locale]) : this(YEAR_QUARTER, locale);
-  DateFormat.HOUR24([locale]) : this(HOUR24, locale);
-  DateFormat.HOUR24_MINUTE([locale]) : this(HOUR24_MINUTE, locale);
-  DateFormat.HOUR24_MINUTE_SECOND([locale]) :
-      this(HOUR24_MINUTE_SECOND, locale);
-  DateFormat.HOUR([locale]) : this(HOUR, locale);
-  DateFormat.HOUR_MINUTE([locale]) : this(HOUR_MINUTE, locale);
-  DateFormat.HOUR_MINUTE_SECOND([locale]) : this(HOUR_MINUTE_SECOND, locale);
-  DateFormat.HOUR_MINUTE_GENERIC_TZ([locale]) :
-      this(HOUR_MINUTE_GENERIC_TZ, locale);
-  DateFormat.HOUR_MINUTE_TZ([locale]) : this(HOUR_MINUTE_TZ, locale);
-  DateFormat.HOUR_GENERIC_TZ([locale]) : this(HOUR_GENERIC_TZ, locale);
-  DateFormat.HOUR_TZ([locale]) : this(HOUR_TZ, locale);
-  DateFormat.MINUTE([locale]) : this(MINUTE, locale);
-  DateFormat.MINUTE_SECOND([locale]) : this(MINUTE_SECOND, locale);
-  DateFormat.SECOND([locale]) : this(SECOND, locale);
-
-  DateFormat.d([locale]) : this("d", locale);
-  DateFormat.E([locale]) : this("E", locale);
-  DateFormat.EEEE([locale]) : this("EEEE", locale);
-  DateFormat.LLL([locale]) : this("LLL", locale);
-  DateFormat.LLLL([locale]) : this("LLLL", locale);
-  DateFormat.M([locale]) : this("M", locale);
-  DateFormat.Md([locale]) : this("Md", locale);
-  DateFormat.MEd([locale]) : this("MEd", locale);
-  DateFormat.MMM([locale]) : this("MMM", locale);
-  DateFormat.MMMd([locale]) : this("MMMd", locale);
-  DateFormat.MMMEd([locale]) : this("MMMEd", locale);
-  DateFormat.MMMM([locale]) : this("MMMM", locale);
-  DateFormat.MMMMd([locale]) : this("MMMMd", locale);
-  DateFormat.MMMMEEEEd([locale]) : this("MMMMEEEEd", locale);
-  DateFormat.QQQ([locale]) : this("QQQ", locale);
-  DateFormat.QQQQ([locale]) : this("QQQQ", locale);
-  DateFormat.y([locale]) : this("y", locale);
-  DateFormat.yM([locale]) : this("yM", locale);
-  DateFormat.yMd([locale]) : this("yMd", locale);
-  DateFormat.yMEd([locale]) : this("yMEd", locale);
-  DateFormat.yMMM([locale]) : this("yMMM", locale);
-  DateFormat.yMMMd([locale]) : this("yMMMd", locale);
-  DateFormat.yMMMEd([locale]) : this("yMMMEd", locale);
-  DateFormat.yMMMM([locale]) : this("yMMMM", locale);
-  DateFormat.yMMMMd([locale]) : this("yMMMMd", locale);
-  DateFormat.yMMMMEEEEd([locale]) : this("yMMMMEEEEd", locale);
-  DateFormat.yQQQ([locale]) : this("yQQQ", locale);
-  DateFormat.yQQQQ([locale]) : this("yQQQQ", locale);
-  DateFormat.H([locale]) : this("H", locale);
-  DateFormat.Hm([locale]) : this("Hm", locale);
-  DateFormat.Hms([locale]) : this("Hms", locale);
-  DateFormat.j([locale]) : this("j", locale);
-  DateFormat.jm([locale]) : this("jm", locale);
-  DateFormat.jms([locale]) : this("jms", locale);
-  DateFormat.jmv([locale]) : this("jmv", locale);
-  DateFormat.jmz([locale]) : this("jmz", locale);
-  DateFormat.jv([locale]) : this("jv", locale);
-  DateFormat.jz([locale]) : this("jz", locale);
-  DateFormat.m([locale]) : this("m", locale);
-  DateFormat.ms([locale]) : this("ms", locale);
-  DateFormat.s([locale]) : this("s", locale);
-
-  /**
-   * ICU constants for format names, resolving to the corresponding skeletons.
-   */
-  static final String DAY = 'd';
-  static final String ABBR_WEEKDAY = 'E';
-  static final String WEEKDAY = 'EEEE';
-  static final String ABBR_STANDALONE_MONTH = 'LLL';
-  static final String STANDALONE_MONTH = 'LLLL';
-  static final String NUM_MONTH = 'M';
-  static final String NUM_MONTH_DAY = 'Md';
-  static final String NUM_MONTH_WEEKDAY_DAY = 'MEd';
-  static final String ABBR_MONTH = 'MMM';
-  static final String ABBR_MONTH_DAY = 'MMMd';
-  static final String ABBR_MONTH_WEEKDAY_DAY = 'MMMEd';
-  static final String MONTH = 'MMMM';
-  static final String MONTH_DAY = 'MMMMd';
-  static final String MONTH_WEEKDAY_DAY = 'MMMMEEEEd';
-  static final String ABBR_QUARTER = 'QQQ';
-  static final String QUARTER = 'QQQQ';
-  static final String YEAR = 'y';
-  static final String YEAR_NUM_MONTH = 'yM';
-  static final String YEAR_NUM_MONTH_DAY = 'yMd';
-  static final String YEAR_NUM_MONTH_WEEKDAY_DAY = 'yMEd';
-  static final String YEAR_ABBR_MONTH = 'yMMM';
-  static final String YEAR_ABBR_MONTH_DAY = 'yMMMd';
-  static final String YEAR_ABBR_MONTH_WEEKDAY_DAY = 'yMMMEd';
-  static final String YEAR_MONTH = 'yMMMM';
-  static final String YEAR_MONTH_DAY = 'yMMMMd';
-  static final String YEAR_MONTH_WEEKDAY_DAY = 'yMMMMEEEEd';
-  static final String YEAR_ABBR_QUARTER = 'yQQQ';
-  static final String YEAR_QUARTER = 'yQQQQ';
-  static final String HOUR24 = 'H';
-  static final String HOUR24_MINUTE = 'Hm';
-  static final String HOUR24_MINUTE_SECOND = 'Hms';
-  static final String HOUR = 'j';
-  static final String HOUR_MINUTE = 'jm';
-  static final String HOUR_MINUTE_SECOND = 'jms';
-  static final String HOUR_MINUTE_GENERIC_TZ = 'jmv';
-  static final String HOUR_MINUTE_TZ = 'jmz';
-  static final String HOUR_GENERIC_TZ = 'jv';
-  static final String HOUR_TZ = 'jz';
-  static final String MINUTE = 'm';
-  static final String MINUTE_SECOND = 'ms';
-  static final String SECOND = 's';
-
-  /** The locale in which we operate, e.g. 'en_US', or 'pt'. */
-  String _locale;
-
-  /**
-   * The full template string. This may have been specified directly, or
-   * it may have been derived from a skeleton and the locale information
-   * on how to interpret that skeleton.
-   */
-  String _pattern;
-
-  /**
-   * We parse the format string into individual fields and store them here.
-   * This is what is actually used to do the formatting.
-   */
-  List<_DateFormatField> _formatFields;
-
-  /**
-   * A series of regular expressions used to parse a format string into its
-   * component fields.
-   */
-  static var _matchers = const [
-      // Quoted String - anything between single quotes, with escaping
-      //   of single quotes by doubling them.
-      // e.g. in the pattern "hh 'o''clock'" will match 'o''clock'
-      const RegExp("^\'(?:[^\']|\'\')*\'"),
-      // Fields - any sequence of 1 or more of the same field characters.
-      // e.g. in "hh:mm:ss" will match hh, mm, and ss. But in "hms" would
-      // match each letter individually.
-      const RegExp(
-        "^(?:G+|y+|M+|k+|S+|E+|a+|h+|K+|H+|c+|L+|Q+|d+|m+|s+|v+|z+|Z+)"),
-      // Everything else - A sequence that is not quotes or field characters.
-      // e.g. in "hh:mm:ss" will match the colons.
-      const RegExp("^[^\'GyMkSEahKHcLQdmsvzZ]+")
-  ];
-
-  /**
-   * Given a format from the user look it up in our list of known skeletons.
-   * If it's there, then use the corresponding pattern for this locale.
-   * If it's not, then treat it as an explicit pattern.
-   */
-  _setPattern(String inputPattern) {
-    // TODO(alanknight): This is an expensive operation. Caching recently used
-    // formats, or possibly introducing an entire "locale" object that would
-    // cache patterns for that locale could be a good optimization.
-    if (!_availableSkeletons.containsKey(inputPattern)) {
-      _pattern = inputPattern;
-    } else {
-      _pattern = _availableSkeletons[inputPattern];
-    }
-    _formatFields = parsePattern(_pattern);
-  }
-
-  /** Return the pattern that we use to format dates.*/
-  get pattern() => _pattern;
-
-  /** Return the skeletons for our current locale. */
-  Map get _availableSkeletons() {
-    return dateTimePatterns[locale];
-  }
-
-  /**
-   * Set the locale. If the locale can't be found, we also look up
-   * based on alternative versions, e.g. if we have no 'en_CA' we will
-   * look for 'en' as a fallback. It will also translate en-ca into en_CA.
-   * Null is also considered a valid value for [newLocale], indicating
-   * to use the default.
-   */
-  _setLocale(String newLocale) {
-    _locale = Intl.verifiedLocale(newLocale);
-  }
-
-  /**
-   * Return true if the locale exists, or if it is null. The null case
-   * is interpreted to mean that we use the default locale.
-   */
-  static bool localeExists(localeName) {
-    if (localeName == null) return false;
-    return dateTimeSymbols.containsKey(localeName);
-  }
-
-  // TODO(alanknight): This can be a variable once that's permitted.
-  static List get _fieldConstructors() => [
-      (pattern, parent) => new _DateFormatQuotedField(pattern, parent),
-      (pattern, parent) => new _DateFormatPatternField(pattern, parent),
-      (pattern, parent) => new _DateFormatLiteralField(pattern, parent)];
-
-  /** Parse the template pattern and return a list of field objects.*/
-  List parsePattern(String pattern) {
-    if (pattern == null) return null;
-    return _reverse(_parsePatternHelper(pattern));
-  }
-
-  /** Recursive helper for parsing the template pattern. */
-  List _parsePatternHelper(String pattern) {
-    if (pattern.isEmpty()) return [];
-
-    var matched = _match(pattern);
-    if (matched == null) return [];
-
-    var parsed = _parsePatternHelper(
-                      pattern.substring(matched.fullPattern().length));
-    parsed.add(matched);
-    return parsed;
-  }
-
-  /** Find elements in a string that are patterns for specific fields.*/
-  _DateFormatField _match(String pattern) {
-    for (var i = 0; i < _matchers.length; i++) {
-      var regex = _matchers[i];
-      var match = regex.firstMatch(pattern);
-      if (match != null) {
-        return _fieldConstructors[i](match.group(0), this);
-      }
-    }
-  }
-
-  /** Polyfill for missing library function. */
-  List _reverse(List list) {
-    // TODO(alanknight): Use standardized list reverse when implemented.
-    // See Issue 2804.
-    var result = new List();
-    for (var i = list.length-1; i >= 0; i--) {
-      result.addLast(list[i]);
-    }
-    return result;
-  }
-}