anchor.diff:                                           (cdr elements-rest))
                                      (setf (cdr prev-elements-rest)
                                            (cdr elements-rest))))
  +                              ((<= pos (+ pos n) start)
  +                               (setf (car elements-rest)
  +                                     (list (- start n) (- end n) value)))
                                 ((< pos start (+ pos n))
                                  (setf (car elements-rest)
                                        (list pos (- end n) value)))
                                 ((<= start pos (+ pos n) end)
                                  (setf (car elements-rest)
  -                                     (list start (- end n))))
  +                                     (list start (- end n) value)))
                                 ((<= start pos end (+ pos n))
                                  (setf (car elements-rest)
  -                                     (list start pos))))))))
  +                                     (list start pos value))))))))
   
   (defun line-property-delete-line (line pos)
     (loop :for plist-rest :on (line-plist line) :by #'cddr
  
positive.code:                                        (setf (cdr prev-elements-rest)
                                               (cdr elements-rest))))
                                    ((<= pos end)
                                     (push (car elements-rest) new-values)
                                     (setf (car elements-rest)
                                           (list start pos value))))))
                  (unless (null new-values)
  
negative.code:                 (cond ((<= pos start)
                         (incf (first v) offset)
                         (incf (second v) offset))
                        ((< start pos end)
                         (incf (second v) offset))
                        ((< pos end)
                         (incf (second v) offset)))))))
  
  (defun line-property-insert-newline (line next-line pos)
    (let ((new-plist '()))
  