Refactor command code and add support for --help and --version.

utils/pub/command_list.dart

 // Copyright (c) 2012, 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.
 
 /** Handles the `list` pub command. */
-void commandList(PubOptions options, List<String> args) {
-  // TODO(rnystrom): Validate args. Right now, this just lists the packages in
-  // your cache.
-  final cache = new PackageCache(options.cacheDir);
-  cache.listAll().then((packages) {
-    for (final package in packages) {
-      print(package.name);
-    }
-  });
-}
+class ListCommand extends PubCommand {
+  String get description() => 'print the contents of repositories';

[nweiz, 2012/04/25 20:49:41]

This isn't really accurate... currently what this does is prints the contents of
the cache.

I'm not sure that's actually the most useful behavior, though. The cache should
be largely transparent to the user. It may make sense as an option, but it seems
like a more useful default would be to print the transitive dependency list of
the current package.

[Bob Nystrom, 2012/04/25 22:56:40]

Right.
Yeah, this command basically exists so that we can get some information out of
pub for some of the early integration tests. If you'd like, we can give it a
more obvious temp name like "debuglist". It's basically here so that I could
write tests of the basic package loading code before any other useful commands
had been written.

[nweiz, 2012/04/25 23:09:22]

Oh, sure. Maybe just add a comment about that here.

[Bob Nystrom, 2012/04/26 00:22:13]

Done.

+
+  void onRun() {
+    cache.listAll().then((packages) {
+      for (final package in packages) {
+        print(package.name);
+      }
+    });
+  }
+}