Scritch a rough outline of a scratch pad using Racket

scritch.rkt

#lang racket/gui
(define f (new (class frame%
                 (super-new))
               [label "Scritch"]
               [width 800]
               [height 600]))
(define c (new editor-canvas% [parent f]))
(define t (new text%))
(send c set-editor t)
(send f show #t)

(define filename "scritch.txt")

(if (file-exists? filename)
    (begin
      (display "File exists, reading content:\n")
      (call-with-input-file filename
        (lambda (in)
          (let ((line (read-line in 'any)))
            (unless (eof-object? line)
              (send t insert line))))))
    (display "File does not exist.\n"))

(define (write-to-file)
  (call-with-output-file filename
    #:exists 'replace
    (lambda (out)
      (write (send t get-text) out)
      (newline out))))


(define timer (new timer% [notify-callback
                (lambda ()
                  (write-to-file)
                  (newline))]
              [interval 5000]))