Adds facilities for extracting Intl.message calls and generating code from translations

pkg/intl/test/message_extraction/generate_from_json.dart

+#!/usr/bin/env dart
+// Copyright (c) 2013, 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.
+
+/**
+ * A main program that takes as input a source Dart file and a number
+ * of JSON files representing translations of messages from the corresponding
+ * Dart file. See extract_to_json.dart and make_hardcoded_translation.dart.
+ *
+ * This produces a series of files named
+ * "messages_<locale>.dart" containing messages for a particular locale
+ * and a main import file named "messages_all.dart" which has imports all of
+ * them and provides an initializeMessages function.
+ */
+library generate_from_json;
+
+import 'dart:io';
+import 'package:intl/extract_messages.dart';
+import 'package:intl/src/intl_message.dart';
+import 'extract_to_json.dart';
+import 'package:intl/generate_localized.dart';
+import 'dart:json' as json;
+import 'package:pathos/path.dart' as path;
+
+/**
+ * Keeps track of all the messages we have processed so far, keyed by message
+ * name.
+ */
+Map<String, IntlMessage> messages;
+
+main() {
+  var args = new Options().arguments;
+  if (args.length == 0) {
+    print('Usage: generate_from_json [originalFiles.dart] '
+        '[translationFiles.json]');
+    exit(0);
+  }
+
+  ifNull(x, y) => (x == null) ? y : x;
+  var target = ifNull(Platform.environment["INTL_MESSAGE_OUTPUT"], '.');
+  var isDart = new RegExp(r'\.dart');
+  var isJson = new RegExp(r'\.json');
+  var dartFiles = args.where(isDart.hasMatch).toList();
+  var jsonFiles = args.where(isJson.hasMatch).toList();
+
+  var allMessages = dartFiles.map((each) => parseFile(new File(each)));
+
+  messages = new Map();
+  for (var eachMap in allMessages) {
+    eachMap.forEach((key, value) => messages[key] = value);
+  }
+  for (var arg in jsonFiles) {
+    var file = new File(path.join(target, arg));
+    var translations = generateLocaleFile(new File(arg));
+  }
+
+  var mainImportFile = new File(path.join(target, 'messages_all.dart'));
+  mainImportFile.writeAsStringSync(generateMainImportFile());
+}
+
+/**
+ * Create the file of generated code for a particular locale. We read the json
+ * data and create [BasicTranslatedMessage] instances from everything,
+ * excluding only the special _locale attribute that we use to indicate the
+ * locale.
+ */
+generateLocaleFile(File file) {
+  var src = file.readAsStringSync();
+  var data = json.parse(src);
+  var locale = data["_locale"];
+  allLocales.add(locale);
+
+  var translations = [];
+  data.forEach((key, value) {
+    if (key[0] != "_") {
+      translations.add(new BasicTranslatedMessage(key, value));
+    }
+  });
+  generateIndividualMessageFile(locale, translations);
+}
+
+/**
+ * A TranslatedMessage that just uses the name as the id and knows how to look
+ * up its original message in our [messages].
+ */
+class BasicTranslatedMessage extends TranslatedMessage {
+  BasicTranslatedMessage(String name, String translated) :
+      super(name, translated);
+
+  get originalMessage =>
+      (super.originalMessage == null) ? _findOriginal() : super.originalMessage;
+
+  // We know that our [id] is the name of the message, which is used as the
+  //key in [messages].
+  _findOriginal() => originalMessage = messages[id];
+}