Modify scanner and parser to be standalone packages.

pkg/dart_parser/lib/src/main.dart

Index: pkg/dart_parser/lib/src/main.dart
diff --git a/pkg/dart_parser/lib/src/main.dart b/pkg/dart_parser/lib/src/main.dart
new file mode 100644
index 0000000000000000000000000000000000000000..830b6f897e9ff3b7f6de2a4b444115f4abadeabe
--- /dev/null
+++ b/pkg/dart_parser/lib/src/main.dart
@@ -0,0 +1,57 @@
+// Copyright (c) 2016, 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.
+
+library parser.main;
+
+import 'dart:convert' show
+    LineSplitter,
+    UTF8;
+
+import 'dart:io' show
+    File;
+
+import 'package:scanner/src/token.dart' show
+    Token;
+
+import 'package:scanner/io.dart' show
+    readBytesFromFileSync;
+
+import 'package:scanner/scanner.dart' show
+    scan;
+
+import 'listener.dart' show
+    Listener;
+
+import 'top_level_parser.dart' show
+    TopLevelParser;
+
+class DebugListener extends Listener {
+  void handleIdentifier(Token token) {
+    logEvent("Identifier: ${token.value}");
+  }
+
+  void logEvent(String name) {
+    print(name);
+  }
+}
+
+main(List<String> arguments) async {
+  for (String argument in arguments) {
+    if (argument.startsWith("@")) {
+      Uri uri = Uri.base.resolve(argument.substring(1));
+      await for (String file in new File.fromUri(uri).openRead()
+                     .transform(UTF8.decoder)
+                     .transform(const LineSplitter())) {
+        outLine(uri.resolve(file));
+      }
+    } else {
+      outLine(Uri.base.resolve(argument));
+    }
+  }
+}
+
+void outLine(Uri uri) {
+  new TopLevelParser(new DebugListener()).parseUnit(

[Johnni Winther, 2017/01/12 13:14:37]

Should the DebugListener be used unconditionally?

[ahe, 2017/01/12 13:57:54]

I think so. This program isn't worth much without that listener. With the debug
listener it prints the events, without it it doesn't do much (except if there is
an error).

+      scan(readBytesFromFileSync(uri)).tokens);
+}