anchor.diff:    }
   
     List<Resource> getChildren() => _localChildren;
  -  /**
  -   * Returns a pre-order traversal of all the children of `this`.
  -   */
  -  Iterable<Resource> walkChildren() => preOrderTraversal(this);
  +
  +  /**
  +   * Returns an iterable of the children of the container as a pre-order traversal
  +   * of the tree of subcontainers and their children.
  +   */
  +  Iterable<Resource> walkChildren() => _workspaceTraversal(this);
  +
  +  static Iterable<Resource> _workspaceTraversal(Resource r) {
  +    if (r is Container) {
  +      return [ [r], r.getChildren().expand((c) => _workspaceTraversal(c)) ]
  +      .expand((i) => i);
  +    } else {
  +      return [r];
  +    }
  +  }
   }
   
   abstract class Resource {
  
positive.code: 
    List<Resource> getChildren() => _localChildren;
  
    Iterable<Resource> walkChildren() => preOrderTraversal(this);
  
    List<File> getFiles() => _localChildren.where((c) => c is File).toList();
  
  
negative.code:   String toString() => '${type}: ${resource}';
  }
  
  
  
  
  