(import (chicken format)) ; format printf
(import srfi-13)          ; string-copy!

(define (string-repeat str n)
  (let* ((slen (string-length str))
         (res (make-string (* slen n))))
   (do ((i 0 (+ i slen))) ((= i n) res)
    (string-copy! res i str))))
    
(define arrow "-->")
(define spacer (string-repeat " " (string-length arrow)))

(define (print-cell val)
  (printf "| ~a | *-|" val))

;;; Convert any value to a string, a hack though
(define (any->number val)
  (format #f "~a" val))

(define (print-top-bottom lst)
  (for-each 
    (lambda (e)
     (let ((vals (any->number e)))
       (printf "+~a+---+~a"
         (string-repeat "-" (+ (string-length vals) 2)) spacer)))
    lst)
  (display "\n"))

;;; Creates a ASCII-art representation of a list
(define (list-ascii lst)
  (print-top-bottom lst)
  (for-each (lambda (c)
             (print-cell c)
             (display arrow))
      lst)
  (display "NIL\n")
  (print-top-bottom lst))

(list-ascii '(1 2 3 4))
(list-ascii '("foo" #x27 "aaaeeeiiiooouuu" 100 28/8))