anchor.diff:      (setf index start)))
   
   (defmethod next ((iter iterator))
  -  (with-slots (index length increment id quiet cyclic initial-element
  -                     comparer bound-check initial-contents) iter
  -    (if (or (funcall bound-check index length) (eq length -1))
  +  (with-slots (index end increment id quiet cyclic initial-element
  +                     accessor bound-check initial-contents) iter
  +    (if (or (funcall bound-check index end) (eq end -1))
           (let ((current
                  (funcall id (cond
  -                             ((not (null initial-contents)) (funcall comparer index initial-contents))
  +                             ((not (null initial-contents)) (funcall accessor index initial-contents))
                                ((not (null initial-element)) initial-element)
                                (T index)))))
             (incf index increment)
  
positive.code:           :documentation "The start of the iteration, either an index value or integer value to mark the start of iteration")
     (index :initform 0
            :documentation "the current index of the iteration") 
     (length :initform -1 :initarg :length
             :documentation "The length of the iteration, -1 denotes an infinite iteration, for lists/sequences, the sequence length limits the iteration")
     (increment :initform 1 :initarg :inc
                :documentation "the increment of the iteration")
     (id :initform #'identity :initarg :id
  
negative.code:                      :documentation "A list/sequence of initial-contents to be iterated")
     (initial-element :initform nil :initarg :initial-element
                      :documentation "When supplied and no initial-contents supplied, iteration returns the value instead of the index")
     (bound-check :initform #'< :initarg :from-end
                  :documentation "When T, direction of iteration is from-end")
     (accessor :initform #'nth
               :documentation "Function to access to individual members of a initial-contents, #'nth for lists, #'elt for others")))
  
  (defmethod reset ((iter iterator))
  