anchor.diff:    }
   
     Map clone() => _cloneMap(target);
  -  
  +
     max([Expr expr]) => List$.fn(target.getValues()).max(expr);
     min([Expr expr]) => List$.fn(target.getValues()).min(expr);
   
  
positive.code:   bool isDate() => e is Date;
    bool isRegExp() => e is RegExp;
    bool isNull() => e == null;
    bool isUndefined() => isNull(); 
    bool isFalsy() => _isFalsy(e); 
    bool isTruthy() => !_isFalsy(e); 
    int size() => e.length;
    bool isEmpty() => e is RegExp ? true : _isFalsy(e);
  
    List toArray() => e == null ? 
        [] : 
      e is List ? 
        _cloneList(e) : 
      e is Map ? 
        (e['toArray'] is Function ?
          e['toArray']() :
          e.getValues())
      : new List.from(e);
          
    void each(f(x)) {
      if (e == null) return;
      if (e is Collection) e.forEach(f);
      else if (e is Map) e.forEach((k,v) => f(v));
    }
    void forEach(f(x)) => each(f);
    
    map(f(x)) {
      if (e == null) return [];
      return e.map(f);
    }
    void collect(f(x)) => map(f);
    
    reduce(f(x,y), [memo]) {
      if (e == null)
        if (memo == null)
  
negative.code:       return args[0];
      };
    }
  
    after(int times) {
      if (times <= 0) return target();
      return ([arg1, arg2, arg3, arg4]) {
        if (--times < 1) return _call(target, arg1, arg2, arg3, arg4);
      };
    }
  
  }
  
  typedef IteratorFn(memo, value);
  