Welcome to the CHICKEN Scheme pasting service

;;
;; Copyright (c) 2016, Luiz de Milon (kori)
;;
;; Permission to use, copy, modify, and/or distribute this software for any
;; purpose with or without fee is hereby granted, provided that the above
;; copyright notice and this permission notice appear in all copies.
;;
;; THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
;; WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
;; MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
;; ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
;; WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
;; ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
;; OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

(use utf8)

(define default-bars '(#\▁ #\▂ #\▃ #\▄ #\▅ #\▆ #\▇ #\█))

; create spark line from list using the bars defined by b
(define spark-line
  (lambda (l b)
    (list->string
      (map (lambda (index)
             (list-ref b index))
           (map
             (lambda (number)
               (quotient
                 (inexact->exact (floor (* (sub1 (length b)) number)))
                 (inexact->exact (floor (apply max l)))))
             l)))))


; spark with default bars
(define spark
  (lambda (l)
    (spark-line l default-bars)))