anchor.diff:  import 'package:path/path.dart' as Path;
   
   
  -build(List<String> args, [FileListFactory fileListFactory]){
  +Future build(List<String> args, [FileListFactory fileListFactory]){
     final opts = BuildOptions.parse(args);
     
     if (fileListFactory == null) {
  
positive.code:   //TODO : several compilers ?
    var compiler = new DirectoryCompiler(directory, modules, fileListFactory,
        srcName:'web.src', outName:'web');
    compiler.start().then((_){
    
      if(opts.clean) compiler.clean();
      
  
negative.code:         .then((_) => Future.wait(opts.removed.map(map('web.src',compiler.removeFile))));
      }
      
      return _done.then((_){
        Iterable files = compiler.fileList.files.values;
        
        final result = new BuildResult();
  