anchor.diff:          [target.substring(0, pos), target.substring(pos + 1)];
     }
   
  -  static String debugString(str) =>
  -    "$str".replaceAll("[", "")
  +  static String debugString(str) {
  +    return "$str".replaceAll("[", "")
             .replaceAll("]", "")
             .replaceAll("{", "")
             .replaceAll("}", "")
             .replaceAll("null", "")
             .replaceAll(" ", "");
  +  }
   }
   
   class List$ extends Mixin {
  
positive.code:       } else { return memo;
      }
        }
      return List$.fn(e).reduce(f,memo);
    }
    void foldl(f(x,y), [memo]) => reduce(f,memo);
    void inject(f(x,y), [memo]) => reduce(f,memo);
  
negative.code:   compact() => filter((value) => _isFalsy(value));
  
    List flatten([shallow=false]) {
      var red = reduce((List memo, value) {
        if (value is Iterable) {
          memo.addAll(shallow ? value : fn(value).flatten());
        } else {
          memo.add(value);
        }
        return memo;
      }, []);
      return red;
    }
  
    uniq([isSorted=false, iterator]) {
  