anchor.diff:    
     String get allowedExtensions => '.mixologist.yaml';
       
  -  Future apply(Transform transform) {
  -    return transform
  +  Future apply(Transform transform) =>
  +    transform
         .primaryInput
         .readAsString()
         .then(yaml.loadYaml)
  
positive.code:               .where((name) => !mixins.containsKey(name)),
              (name) => transform
                .getInput(new AssetId(transform.primaryInput.id.package,
                    '${_prefixFrom(transform.primaryInput.id)}$path/name.dart'))
                .then((asset) => asset.read())
                .then((byteStream) => byteStream.pipe(
                    new mixologist.MixinReader()))
  
negative.code:         transform.addOutput(new Asset.fromString(id, lines.join('\n')));
        })
      );
  }
  
  String _prefixFrom(AssetId asset) => (asset.path.split('/')..removeLast()..add('')).join('/');