(DE SAVE (XX)
  (SETQ STACK (CONS XX STACK))
  (IF OKP (PRINT ['H-STACK '/= (LENGTH STACK)])))

(DE RESTORE () (NEXTL STACK))

(DE UNREC () (SETQ  PC (NEXTL STACK)))

;;

;;;      BINDING AND UNBINDING FUNCTIONS ;
;;

(DE REBIND (XX YY) 
  (WHILE XX
         (SET (NEXTL XX) (NEXTL YY))))