Async initialization for DateFormat

pkg/intl/date_symbol_data_file.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.
+
+/**
+ * This file should be imported, along with date_format.dart in order to read
+ * locale data from files in the file system.
+ */
+
+#library('date_symbol_data_json');
+
+#import("date_symbols.dart");
+#import("lib/lazy_locale_data.dart");
+#import('lib/date_format_internal.dart');
+#import('lib/file_data_reader.dart');
+#import('dart:io');
+
+#source("data/dates/localeList.dart");
+
+/**
+ * This should be called for at least one [locale] before any date formatting
+ * methods are called. It sets up the lookup for date symbols using [path].
+ * The [path] parameter should end with a directory separator: '/' or '\' as

[Emily Fortuna, 2012/09/05 01:06:21]

'\' should be => '\\', right? Or better -- just get rid of the '/' or '\' and
just say as appropriate for the platform.

[Alan Knight, 2012/09/05 19:56:02]

Done.

+ * appropriate for the platform.
+ */
+Future initializeDateFormatting(String locale, String path) {
+  var reader = new FileDataReader('${path}symbols${Platform.pathSeparator}');
+  initializeDateSymbols(() => new LazyLocaleData(
+      reader, _createDateSymbol, availableLocalesForDateFormatting));
+  var reader2 = new FileDataReader('${path}patterns${Platform.pathSeparator}');
+  initializeDatePatterns(() => new LazyLocaleData(
+      reader2, (x) => x, availableLocalesForDateFormatting));
+  return initializeIndividualLocaleDateFormatting(
+      (symbols, patterns) {
+        return Futures.wait([
+            symbols.initLocale(locale),
+            patterns.initLocale(locale)]);
+      });
+}
+
+/** Defines how new date symbol entries are created. */
+DateSymbols _createDateSymbol(Map map) {
+  return new DateSymbols.deserializeFromMap(map);
+}