parent-script.scm

(use gauche.process)
(use rfc.http)

(define (spawn-and-talk-to-server)
  (let* ([p (run-process '("gosh" "./server-script.scm") :wait #f :output :pipe)]
         [s (read-line (process-output p))])
    (unwind-protect
        (and (string? s) (#/^\d+$/ s)
             (http-get #"localhost:~s" "/"))
      (process-kill p)
      (process-wait p))))