Adding support for number formating to the JS i18n API.

src/extensions/experimental/i18n.js

Index: src/extensions/experimental/i18n.js
===================================================================
--- src/extensions/experimental/i18n.js	(revision 8248)
+++ src/extensions/experimental/i18n.js	(working copy)
@@ -223,6 +223,96 @@
 };
 
 /**
+ * NumberFormat class implements locale-aware number formatting.
+ * Constructor is not part of public API.
+ * @param {Object} locale - locale object to pass to formatter.
+ * @param {Object} settings - formatting flags:
+ *   - skeleton
+ *   - pattern
+ *   - style - decimal, currency, percent or scientific
+ *   - currencyCode - ISO 4217 3-letter currency code
+ * @private
+ * @constructor
+ */
+v8Locale.__NumberFormat = function(locale, settings) {
+  native function NativeJSNumberFormat();
+
+  settings = v8Locale.__createSettingsOrDefault(settings, {});
+
+  var cleanSettings = {};
+  if (settings.hasOwnProperty('skeleton')) {
+    cleanSettings['skeleton'] = settings['skeleton'];
+  } else if (settings.hasOwnProperty('pattern')) {
+    cleanSettings['pattern'] = settings['pattern'];
+  } else {
+    cleanSettings = {};
+    if (settings.hasOwnProperty('style')) {
+      var style = settings['style'];
+      if (!/^decimal|currency|percent|scientific$/.test(style)) {
+        style = 'decimal';
+      }
+      cleanSettings['style'] = style;
+    }
+  }
+
+  // Default is to show decimal style.
+  if (!cleanSettings.hasOwnProperty('skeleton') &&
+      !cleanSettings.hasOwnProperty('pattern') &&
+      !cleanSettings.hasOwnProperty('style')) {
+    cleanSettings = {'style': 'decimal'};
+  }
+
+  // Add currency code if available and valid (3-letter ASCII code).
+  if (settings.hasOwnProperty('currencyCode') &&
+      /^[a-zA-Z]{3}$/.test(settings['currencyCode'])) {

[jungshik at Google, 2011/06/16 18:08:19]

Is it your intent to allow mixed-case 3-letter code?  

[Nebojša Ćirić, 2011/06/17 17:48:45]

I don't think it's a problem to allow that in this case. User can do EUR or eur,
or less likely EUr.

On 2011/06/16 18:08:19, Jungshik Shin wrote:

+    cleanSettings['currencyCode'] = settings['currencyCode'].toUpperCase();

[jungshik at Google, 2011/06/16 18:08:19]

It looks like it's assumed that v8's toUpperCase will remain always
locale-independent (i.e. acting like POSIX locale : [a-z] => [A-Z]).  At least,
add a comment about that. 

[Nebojša Ćirić, 2011/06/17 17:48:45]

It's locale independent. There is a locale depended version - toLocaleUpperCase
(https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/String/t...).

On 2011/06/16 18:08:19, Jungshik Shin wrote:

+  }
+
+  locale = v8Locale.__createLocaleOrDefault(locale);
+  // Pass in region ID for proper currency detection. Use ZZ if region is empty.
+  var region = locale.options.regionID !== '' ? locale.options.regionID : 'ZZ';
+  var formatter = NativeJSNumberFormat(
+      locale.__icuLocaleID, 'und_' + region, cleanSettings);
+
+  for (key in cleanSettings) {
+    // Don't overwrite keys that are alredy in.
+    if (formatter.hasOwnProperty(key)) continue;
+
+    formatter.options[key] = cleanSettings[key];
+  }
+
+  /**
+   * Clones existing number format with possible overrides for some
+   * of the options.
+   * @param {!Object} overrideSettings - overrides for current format settings.
+   * @returns {Object} - new or cached NumberFormat object.
+   * @public
+   */
+  formatter.derive = function(overrideSettings) {
+    // To remove a setting user can specify undefined as its value. We'll remove
+    // it from the map in that case.
+    for (var prop in overrideSettings) {
+      if (settings.hasOwnProperty(prop) && !overrideSettings[prop]) {
+        delete settings[prop];
+      }
+    }
+    return new v8Locale.__NumberFormat(
+        locale, v8Locale.__createSettingsOrDefault(overrideSettings, settings));
+  };
+
+  return formatter;
+};
+
+/**
+ * Creates new NumberFormat based on current locale.
+ * @param {Object} - formatting flags. See constructor.
+ * @returns {Object} - new or cached NumberFormat object.
+ */
+v8Locale.prototype.createNumberFormat = function(settings) {
+  return new v8Locale.__NumberFormat(this, settings);
+};
+
+/**
  * Merges user settings and defaults.
  * Settings that are not of object type are rejected.
  * Actual property values are not validated, but whitespace is trimmed if they