Roll Observatory packages and add a roll script

packages/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,
+      help: 'Suppress printing of warnings.');
+  parser.addFlag("warnings-are-errors",
+      defaultsTo: false,
+      callback: (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,
+      help: 'Specify the output directory.');
+  parser.parse(args);
+  if (args.length == 0) {
+    print('Accepts Dart files and produces intl_messages.json');
+    print('Usage: extract_to_arb [options] [files.dart]');
+    print(parser.usage);
+    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) {
+    exit(1);
+  }
+}
+
+/**
+ * This is a placeholder for transforming a parameter substitution from
+ * the translation file format into a Dart interpolation. In our case we
+ * store it to the file in Dart interpolation syntax, so the transformation
+ * is trivial.
+ */
+String leaveTheInterpolationsInDartForm(MainMessage msg, chunk) {
+  if (chunk is String) return chunk;
+  if (chunk is int) return "\$${msg.arguments[chunk]}";
+  return chunk.toCode();
+}
+
+/**
+ * Convert the [MainMessage] to a trivial JSON format.
+ */
+Map toARB(MainMessage message) {
+  if (message.messagePieces.isEmpty) return null;
+  var out = {};
+  out[message.name] = icuForm(message);
+  out["@${message.name}"] = arbMetadata(message);
+  return out;
+}
+
+Map arbMetadata(MainMessage message) {
+  var out = {};
+  var desc = message.description;
+  if (desc != null) {
+    out["description"] = desc;
+  }
+  out["type"] = "text";
+  var placeholders = {};
+  for (var arg in message.arguments) {
+    addArgumentFor(message, arg, placeholders);
+  }
+  out["placeholders"] = placeholders;
+  return out;
+}
+
+void addArgumentFor(MainMessage message, String arg, Map result) {
+  var extraInfo = {};
+  if (message.examples != null && message.examples[arg] != null) {
+    extraInfo["example"] = message.examples[arg];
+  }
+  result[arg] = extraInfo;
+}
+
+/**
+ * Return a version of the message string with
+ * with ICU parameters "{variable}" rather than Dart interpolations "$variable".
+ */
+String icuForm(MainMessage message) =>
+    message.expanded(turnInterpolationIntoICUForm);
+
+String turnInterpolationIntoICUForm(Message message, chunk,
+    {bool shouldEscapeICU: false}) {
+  if (chunk is String) {
+    return shouldEscapeICU ? escape(chunk) : chunk;
+  }
+  if (chunk is int && chunk >= 0 && chunk < message.arguments.length) {
+    return "{${message.arguments[chunk]}}";
+  }
+  if (chunk is SubMessage) {
+    return chunk.expanded((message, chunk) =>
+        turnInterpolationIntoICUForm(message, chunk, shouldEscapeICU: true));
+  }
+  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("}", "'}'");
+}