anchor.diff:    "If FUNCTION is not NIL, apply it."
     (when function (apply #'apply function args)))
   
  -;;; Remove keyword pairs from an argument list, consing as little as possible
  -
  +;;; Remove keyword pairs from an argument list, consing as little as
  +;;; possible.
   (defun remove-keywords (arg-list keywords)
     (let ((clean-tail arg-list))
       ;; First, determine a tail in which there are no keywords to be removed.
  
positive.code:          new-values-set-form old-values-set-form
           update-form)
      (loop for (place new-value) in forms
         for (vars vals store-vars writer-form reader-form)
           = (multiple-value-list (get-setf-expansion place env))
         for old-value-names = (mapcar (lambda (var)
                                         (declare (ignore var))
                                         (gensym))
                                       store-vars)
         nconc (mapcar #'list vars vals) into temp-init-let-form
         nconc (copy-list store-vars) into temp-init-let-form
         nconc (copy-list old-value-names) into temp-init-let-form
         nconc `(,(valueify old-value-names) ,reader-form) into temp-save-old-values-setf-form
         nconc `(,(valueify store-vars) ,new-value) into temp-new-values-set-form
         nconc `(,(valueify store-vars) ,(valueify old-value-names)) into temp-old-values-set-form
         collect writer-form into temp-update-form
         finally (setq init-let-form temp-init-let-form
                       save-old-values-setf-form temp-save-old-values-setf-form
                       new-values-set-form temp-new-values-set-form
                       old-values-set-form temp-old-values-set-form
                       update-form (cons 'progn temp-update-form)))
      `(let* ,init-let-form
         (setf ,@save-old-values-setf-form)
         (unwind-protect
  
negative.code: 	    nconc clean-tail
  	    and do (loop-finish)
  	  else if (not (member key keywords :test #'eq))
  		 nconc (list key value)
  	  end)))
  
  (defmacro with-keywords-removed ((var keywords &optional (new-var var))
  