Formatter code transform bit-flip support.

pkg/analyzer_experimental/bin/formatter.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.
 
 import 'dart:convert';
 import 'dart:io';
 import 'dart:utf';
 
 import 'package:args/args.dart';
 import 'package:path/path.dart' as path;
 
 import 'package:analyzer_experimental/src/services/formatter_impl.dart';
 
 
 const BINARY_NAME = 'dartfmt';
 final dartFileRegExp = new RegExp(r'^[^.].*\.dart$', caseSensitive: false);
 final argParser = _initArgParser();
+final defaultSelection = new Selection(-1, -1);
 
 bool machineFormat;
 bool overwriteFileContents;
 Selection selection;
 const followLinks = false;
 
 main() {
   var options = argParser.parse(new Options().arguments);
   if (options['help']) {
     _printUsage();
     return;
   }
 
   _readOptions(options);
-  
+
   if (options.rest.isEmpty) {
     _formatStdin(options);
   } else {
     _formatPaths(options.rest);
   }
 }
 
 _readOptions(options) {
   machineFormat = options['machine'];
   overwriteFileContents = options['write'];
@@ skipping 70 matching lines @@
   // NOTE: these flags are placeholders only!
   var parser = new ArgParser();
   parser.addFlag('write', abbr: 'w', negatable: false,
       help: 'Write reformatted sources to files (overwriting contents).  '
             'Do not print reformatted sources to standard output.');
   parser.addFlag('machine', abbr: 'm', negatable: false,
       help: 'Produce output in a format suitable for parsing.');
   parser.addOption('selection', abbr: 's',
       help: 'Specify selection information as an offset,length pair '
             '(e.g., -s "0,4").');
+  parser.addFlag('transform', abbr: 't', negatable: true,
+      help: 'Perform code transformations.');
   parser.addFlag('help', abbr: 'h', negatable: false,
       help: 'Print this usage information.');
   return parser;
 }
 
 
 /// Displays usage information.
 _printUsage() {
   var buffer = new StringBuffer();
   buffer..write('$BINARY_NAME formats Dart programs.')
         ..write('\n\n')
         ..write('Without an explicit path, $BINARY_NAME processes the standard '
                 'input.  Given a file, it operates on that file; given a '
                 'directory, it operates on all .dart files in that directory, '
                 'recursively. (Files starting with a period are ignored.) By '
                 'default, $BINARY_NAME prints the reformatted sources to '
                 'standard output.')
         ..write('\n\n')
         ..write('Supported flags are:')
         ..write('Usage: $BINARY_NAME [flags] [path...]\n\n')
         ..write('${argParser.getUsage()}\n\n');
   _log(buffer.toString());
 }
 
 /// Format the given [src] as a compilation unit.
 String _formatCU(src, {options: const FormatterOptions()}) {
   var formatResult = new CodeFormatter(options).format(
       CodeKind.COMPILATION_UNIT, src, selection: selection);
   if (machineFormat) {
+    if (formatResult.selection == null) {
+      formatResult.selection = defaultSelection;
+    }
     return _toJson(formatResult);
   }
   return formatResult.source;
 }
 
-_toJson(formatResult) => 
+_toJson(formatResult) =>
     // Actual JSON format TBD
     JSON.encode({'source': formatResult.source,
                  'selection': {
                      'offset': formatResult.selection.offset,
                      'length': formatResult.selection.length
                   }
     });
 
 /// Log the given [msg].
 _log(String msg) {
   //TODO(pquitslund): add proper log support
   print(msg);
 }