update.lisp

(defmacro update/fn-1! (generaized-variable update-fn &rest args)
  (let ((old-val (gensym)))
    `(let ((,old-val ,generaized-variable))
      (setf ,generaized-variable (funcall ,update-fn ,old-val ,@args))
      ,old-val)))

(defmacro update/fn-2! (generaized-variable update-fn &rest args)
  `(setf ,generaized-variable (funcall ,update-fn ,generaized-variable ,@args)))

(defmacro update/fn-r-1 (generaized-variable update-fn &rest args)
  (let ((old-val (gensym)))
    `(let ((,old-val ,generaized-variable))
      (setf ,generaized-variable (funcall ,update-fn  ,@args ,old-val))
      ,old-val))
  
(defmacro update/fn-r-2! (generaized-variable update-fn &rest args)
  `(setf ,generaized-variable (funcall ,update-fn ,@args ,generaized-variable )))