Find the system locale from the browser or OS

pkg/intl/intl.dart

Index: pkg/intl/intl.dart
===================================================================
--- pkg/intl/intl.dart	(revision 12455)
+++ pkg/intl/intl.dart	(working copy)
@@ -106,7 +106,7 @@
     if (_localeExists(newLocale)) {
       return newLocale;
     }
-    for (var each in [_canonicalized(newLocale), _shortLocale(newLocale)]) {
+    for (var each in [canonicalizedLocale(newLocale), _shortLocale(newLocale)]) {
       if (_localeExists(each)) {
         return each;
       }
@@ -124,7 +124,7 @@
    * Return a locale name turned into xx_YY where it might possibly be
    * in the wrong case or with a hyphen instead of an underscore.
    */
-  static String _canonicalized(String aLocale) {
+  static String canonicalizedLocale(String aLocale) {
     // Locales of length < 5 are presumably two-letter forms, or else malformed.
     // Locales of length > 6 are likely to be malformed. In either case we
     // return them unmodified and if correct they will be found.
@@ -152,7 +152,7 @@
   static String withLocale(String locale, Function msg_function) {
     // We have to do this silliness because Locale is not known at compile time,
     // but must be a static variable.
-    if (_defaultLocale == null) _defaultLocale = _getDefaultLocale();
+    if (_defaultLocale == null) _defaultLocale = systemLocale;
     var oldLocale = _defaultLocale;
     _defaultLocale = locale;
     var result = msg_function();
@@ -175,14 +175,20 @@
   }
 
   /**
+   * The system's locale, as obtained from the window.navigator.language
+   * or other operating system mechanism. Note that due to system limitations
+   * this is not automatically set, and must be set by importing one of
+   * intl_browser.dart or intl_standalone.dart and calling findSystemLocale().
+   */
+  // TODO(alanknight): Detect this without forcing the jump through hoops.
+  // Issue 5171.
+  static String systemLocale = 'en_US';

[Emily Fortuna, 2012/09/17 21:26:38]

in that case, should by default we make systemLocale = '' or null, to ensure
that the user ends up with the locale they want?

Also, if we're making another class field, let's move it up with the other
fields at the top of this file

[Alan Knight, 2012/09/17 22:16:18]

Default: The user may not call either of these mechanisms, so I wanted to give
it a default that would at least do something rather than just failing. If we
can make this happen transparently, then we wouldn't need a default value.

Moving up: Done.

+
+  /**
    * Helper to detect the locale as defined at runtime.
    */
   static String _getDefaultLocale() {
-    // TODO(efortuna): Detect the default locale given the user preferences.
-    // That would mean using window.navigator.language in a browser or
-    // an environment variable or other OS mechanism for the standalone VM.
-    // Yay, hard-coding for now!
-    return 'en_US';
+    return systemLocale;
   }
 
   /**
@@ -191,7 +197,7 @@
    * locale.
    */
   static String getCurrentLocale() {
-    if (_defaultLocale == null) _defaultLocale = _getDefaultLocale();
+    if (_defaultLocale == null) _defaultLocale = systemLocale;

[Emily Fortuna, 2012/09/17 21:26:38]

if you add this systemLocale variable, the necessity for the _getDefaultLocale()
function goes away. Can we just get rid of it?

[Alan Knight, 2012/09/17 22:16:18]

Yes. I think I'd thought that but then forgot. Done.

     return _defaultLocale;
   }
 }