anchor.diff:  (defmethod field-writer ((field form-field))
     (or (slot-value field 'writer)
         (and (field-accessor field)
  -           (fdefinition `(setf ,(field-accessor field)))))) 
  +           (fdefinition `(setf ,(field-accessor field))))))
   
   (defmethod field-value ((field form-field))
     (if (and (field-reader field) (form-model (field-form field)))
  
positive.code:                                (field-name form-field))))))
      ((and (not (field-required-p form-field))
            (empty-value-p (field-value form-field)))
            (values t nil))
      (t (call-next-method))))
  
  (defmethod validate-form-field ((form-field form-field))
  
negative.code:     `(setf (get ',form-name :form)
             (lambda ,args
               (let ((,form (progn ,@body)))
                 (check-type ,form forms:form)
                 (setf (form-name ,form) ',form-name)
                 ,form)))))
  
  