anchor.diff:  
   (defun generate-simple-defstruct-list-constructor (leader-name slots name area)
     `(defun ,name (&key ,@(mapcar (lambda (slot)
  -                                  (list (first slot) (third slot)))
  +                                  (list (structure-slot-name slot) (structure-slot-initform slot)))
                                   slots))
        (list ,@(when leader-name (list `',leader-name))
  -           ,@(mapcar 'first slots))))
  +           ,@(mapcar #'structure-slot-name slots))))
   
   (defun generate-defstruct-list-constructor (leader-name slots name lambda-list area)
     (multiple-value-bind (required optional rest enable-keys keys allow-other-keys aux)
  
positive.code: 				   (mapcar #'cadar keys)
  				   (remove 'nil (mapcar #'third keys))
  				   (mapcar #'first aux)))
  	   (default-slots (set-difference (mapcar #'first slots) assigned-slots)))
        `(defun ,name ,lambda-list
           (vector ,@(when leader-name (list `',leader-name))
                   ,@(mapcar (lambda (s)
                               (if (member (first s) default-slots)
                                   (third s)
                                   (first s)))
                             slots))))))
  
  (defun compute-defstruct-slots (conc-name slot-descriptions included-structure included-slot-descriptions)
  
negative.code:            (mapcar (lambda (s)
                       (incf n)
                       `(progn
                          (defun ,(structure-slot-accessor s) (object)
                            ,@(when (and named predicate)
                                (list `(check-type object (satisfies ,predicate))))
                            (nth ,n object))
                          ,@(unless (structure-slot-read-only s)
                              (list `(defun (setf ,(structure-slot-accessor s)) (new-value object)
                                       ,@(when (and named predicate)
                                           (list `(check-type object (satisfies ,predicate))))
                                       (setf (nth ,n object) (the ,(structure-slot-type s) new-value)))))))
                     slots))
         ,@(mapcar (lambda (x)
                     (if (symbolp x)
  