(let* ((unparsers (json-unparsers))
       (unparse-alist (alist-ref list? unparsers))
       (unparse-vector (alist-ref vector? unparsers)))
  (json-unparsers
   (append (list (cons hash-table? (compose unparse-alist hash-table->alist))
		 (cons list? (compose unparse-vector list->vector)))
	   unparsers)))