anchor.diff:    compact() => filter((value) => _isFalsy(value));
   
     List flatten([shallow=false]) {
  -    return reduce((List memo, value) {
  -      if (value is List) {
  +    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]) {
  
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:         [target.substring(0, pos), target.substring(pos + 1)];
    }
  
    static String debugString(str) {
      return "$str".replaceAll("[", "")
            .replaceAll("]", "")
            .replaceAll("{", "")
            .replaceAll("}", "")
            .replaceAll("null", "")
            .replaceAll(" ", "");
    }
  }
  
  class List$ extends Mixin {
  