LISPUSER

LOOP マクロによる AA 折れ線グラフ

Common Lisp のループマクロによる AA 降れ線グラフ (Haskell 版 , Scheme 版 (2006/03/14 21:31:12 PST))

CL-USER> (plot "RCRFCRFFCCRFFRRCRRCCFRFRFF")
                  __
                 /  \/\/\
 _/\_/\        _/        \
/      \__/\  /
            \/
NIL
CL-USER> 

バリバリ値を書きかえてみる．

(defun plot (data &aux (top 0) (bottom 0) (current 0))
  (labels ((parse (cur pos char)
             (setf current cur
                   top     (max top current)
                   bottom  (min bottom current))
             (cons pos char))
           (aa-plot (buf)
             (loop for n from top downto bottom do
                   (loop for (i . char) in buf do
                         (write-char (if (= i n) char #\space)))
                   (terpri))))
    (aa-plot
     (loop for c across data collect
           (case c
             (#\R (parse (1+ current) current #\/))
             (#\F (parse (1- current) (1- current) #\\))
             (#\C (parse current current #\_)))))))

が，Scheme 版より長かったです．