anchor.diff:            *kill-ring-max*
             *kill-new-flag*
             *kill-before-p*
  -          *kill-disable-p*
             kill-append
             kill-push
             yank
  
positive.code: 
  (defvar *kill-new-flag* t)
  (defvar *kill-before-p* nil)
  (defvar *kill-disable-p* nil)
  
  (defun kill-append (lines before-p)
    (setf (car *kill-ring*)
  
negative.code:         (kill-ring-nth n)))
  
  (defmacro with-kill (() &body body)
    `(progn
       (when-interrupted-flag :kill
                              (setq *kill-new-flag* t))
       ,@body))
  