gistfile1.rkt

#lang racket

(define (emit s) s)

(define (process-file in out)
  (with-input-from-file in
    (lambda ()
      (with-output-to-file out
        #:exists 'replace
        (lambda ()
          (let loop ([sexp (read)])
            (if (eof-object? sexp)
              #f
              (begin 
                (display (emit sexp))
                (loop (read))))))))))

(process-file "in.isw" "out.scm")