commander-s/scheme/tty-debug.scm

(define *tty-port* #f)

(define (init-tty-debug-output!)
  (call-with-values 
      open-pty
    (lambda (input-port name)
      (set! *tty-port* (dup->outport input-port))
      (close input-port)
      (set-port-buffering *tty-port* bufpol/none)
      name)))

(define debug-message
  (lambda args
    (with-current-output-port*
     *tty-port*
     (lambda ()
       (for-each display args)
       (newline)))))