;;;*******************************************************************
;;; digirdr.lsp - Translate digits to words
;;; 2016 David Meyer <papa@sdf.org> +JMJ
;;;*******************************************************************

(defun digiword (d)
  (cond
   ((not (numberp d)) 'error)
   ((or (< d 0) (> d 9)) 'error)
   ((= d 0) "zero")
   ((= d 1) "one")
   ((= d 2) "two")
   ((= d 3) "three")
   ((= d 4) "four")
   ((= d 5) "five")
   ((= d 6) "six")
   ((= d 7) "seven")
   ((= d 8) "eight")
   ((= d 9) "nine")))

(defun digilst (n)
  (digilst-r n nil))

(defun digilst-r (n l)
  (cond
   ((< n 10) (append l (list n)))
   (t (append (digilst-r (quotient n 10) l) (list (remainder n 10))))))