scheme-textplot/plot.body.scm

#!/usr/bin/env scheme-r7rs

; This is a library for plotting a function with text
(define (plot f y-min y-max x-min x-max text-height text-width)
  (define delta-x (/ (- x-max x-min) text-width))
  (define delta-y (/ (- y-max y-min) text-height))
  (let row-loop ((row 0)
                 (y y-max))
    (if (< row text-height)
        (let col-loop ((col 0)
                       (x x-min))
          (if (< col text-width)
              (begin
                (if (< y (f x))
                    (display "*")
                    (display " "))
                (col-loop (+ col 1)
                          (+ x delta-x)))
              (begin
                (newline)
                (row-loop (+ row 1)
                          (- y delta-y))))))))