Add a flag to prohibit plurals/genders that don't take up the whole string.

pkg/intl/bin/extract_to_arb.dart

 #!/usr/bin/env dart
 // Copyright (c) 2014, 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 script uses the extract_messages.dart library to find the Intl.message
  * calls in the target dart files and produces ARB format output. See
  * https://code.google.com/p/arb/wiki/ApplicationResourceBundleSpecification
  */
 library extract_to_arb;
 
 import 'dart:convert';
 import 'dart:io';
 import 'package:intl/extract_messages.dart';
 import 'package:path/path.dart' as path;
 import 'package:intl/src/intl_message.dart';
 import 'package:args/args.dart';
 
 main(List<String> args) {
   var targetDir;
   var parser = new ArgParser();
   parser.addFlag("suppress-warnings", defaultsTo: false, callback: (x) =>
-      suppressWarnings = x);
+      suppressWarnings = x, help: 'Suppress printing of warnings.');
   parser.addFlag("warnings-are-errors", defaultsTo: false, callback: (x) =>
-      warningsAreErrors = x);
+      warningsAreErrors = x,
+      help: 'Treat all warnings as errors, stop processing ');
+  parser.addFlag("embedded-plurals", defaultsTo: true,
+      callback: (x) => allowEmbeddedPluralsAndGenders = x,
+      help: 'Allow plurals and genders to be embedded as part of a larger '
+          'string, otherwise they must be at the top level.');
 
   parser.addOption("output-dir", defaultsTo: '.', callback: (value) => targetDir
-      = value);
+      = value, help: 'Specify the output directory.');
   parser.parse(args);
   if (args.length == 0) {
-    print('Usage: extract_to_arb [--output-dir=<dir>] [files.dart]');
     print('Accepts Dart files and produces intl_messages.json');
+    print('Usage: extract_to_arb [options] [files.dart]');
+    print(parser.getUsage());
     exit(0);
   }
   var allMessages = {};
   for (var arg in args.where((x) => x.contains(".dart"))) {
     var messages = parseFile(new File(arg));
     messages.forEach((k, v) => allMessages.addAll(toARB(v)));
   }
   var file = new File(path.join(targetDir, 'intl_messages.arb'));
   file.writeAsStringSync(JSON.encode(allMessages));
   if (hasWarnings && warningsAreErrors) {
@@ skipping 70 matching lines @@
   if (chunk is Message) {
     return chunk.expanded((message, chunk) => turnInterpolationIntoICUForm(
         message, chunk, shouldEscapeICU: shouldEscapeICU));
   }
   throw new FormatException("Illegal interpolation: $chunk");
 }
 
 String escape(String s) {
   return s.replaceAll("'", "''").replaceAll("{", "'{'").replaceAll("}", "'}'");
 }