Questions about (open-input-output-pipe

[luhux]

Hello everyone

I am a newbie to guile and I am learning to use guile to write scripts

I want to implement this shell command:


wg pubkey < private > public



This is a command to generate a key,
It inputs private key and EOF from stdin, then it outputs the public key and 
exits.

I implemented it using the following code in guile:



(use-modules (ice-9 popen)
             (ice-9 rdelim))

(define (wg-gen-private-key)
  (let* ((port (open-input-pipe "wg genkey"))
        (result (read-line port)))
    (close-pipe port)
    result))

(define (wg-gen-public-key private-key)
  (let ((port (open-input-output-pipe "wg pubkey")))
    (display private-key port)
    (let ((result (read-line port)))
      (close-port port)
      result)))


Then I executed the code to get the public key




scheme@(guile-user)> (wg-gen-public-key (wg-gen-private-key))




but the code got stuck in this place:




    (let ((result (read-line port)))




How should I do?

There are too few Guile information on the Internet. Sorry for asking such a 
basic question.

luhux