From: "Ludovic Courtès" <ludo@gnu.org>
To: Fredrik Salomonsson <plattfot@posteo.net>
Cc: 55420@debbugs.gnu.org
Subject: [bug#55420] [PATCH 0/2] Add a function to parse emacs elisp's package header
Date: Thu, 02 Jun 2022 15:44:53 +0200 [thread overview]
Message-ID: <87fsknp4bu.fsf@gnu.org> (raw)
In-Reply-To: <87zgivai89.fsf@d2.com> (Fredrik Salomonsson's message of "Thu, 02 Jun 2022 02:53:42 +0000")
Hi,
Fredrik Salomonsson <plattfot@posteo.net> skribis:
> Here is what I have so far:
>
> (define-condition-type &emacs-batch-error &error
> emacs-batch-error?
> (expression emacs-batch-error-expression)
> (message emacs-batch-error-message))
>
> (define (emacs-batch-script expr)
> "Execute the Elisp code EXPR in Emacs batch mode and return output."
> (let* ((error-pipe (open-output-string))
> (pipe (with-error-to-port error-pipe
> (lambda ()
> (open-pipe*
> OPEN_READ
> (%emacs) "--quick" "--batch"
> (string-append "--eval=" (expr->string expr))))))
> (output (read-string pipe))
> (error (get-output-string error-pipe))
> (status (close-pipe pipe)))
> (unless (zero? status)
> (raise (condition (&emacs-batch-error
> (expression expr)
> (message error)))))
> output))
Unfortunately ‘open-pipe*’ is not smart enough to redirect stderr to a
non-file port (a string port in this case).
One way around it would be to merge stdout and stderr, like so:
(parameterize ((current-error-port (current-output-port)))
(open-pipe* …))
but then you get both on the same stream, which could be a problem for
instance if Emacs emits warnings and such.
You could work around it by establishing a second pipe:
(match (pipe)
((stderr-input . stderr-output)
(parameterize ((current-error-port stderr-output))
(open-pipe* …))))
Here you should be able to read, in the parent process, from
‘stderr-input’.
Another option is to not try to capture stderr: after all, that’ll get
printed on the screen anyway.
HTH,
Ludo’.
next prev parent reply other threads:[~2022-06-02 13:46 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-14 23:00 [bug#55420] [PATCH 0/2] Add a function to parse emacs elisp's package header Fredrik Salomonsson
2022-05-14 23:05 ` [bug#55420] [PATCH 1/2] guix: emacs-utils: Add emacs-batch-script Fredrik Salomonsson
2022-05-14 23:05 ` [bug#55420] [PATCH 2/2] guix: emacs-utils: Add emacs-header-parse Fredrik Salomonsson
2022-06-01 20:39 ` [bug#55420] [PATCH 0/2] Add a function to parse emacs elisp's package header Ludovic Courtès
2022-06-01 20:38 ` Ludovic Courtès
2022-06-02 2:53 ` Fredrik Salomonsson
2022-06-02 13:44 ` Ludovic Courtès [this message]
2022-06-05 0:42 ` Fredrik Salomonsson
2022-06-05 0:19 ` [bug#55420] [PATCH v2 1/2] guix: emacs-utils: Add emacs-batch-script Fredrik Salomonsson
2022-06-05 0:19 ` [bug#55420] [PATCH v2 2/2] guix: emacs-utils: Add emacs-header-parse Fredrik Salomonsson
2022-06-05 9:52 ` [bug#55420] [PATCH v2 1/2] guix: emacs-utils: Add emacs-batch-script Maxime Devos
2022-06-05 20:02 ` Fredrik Salomonsson
2022-06-05 19:51 ` [bug#55420] [PATCH v3 " Fredrik Salomonsson
2022-06-05 19:51 ` [bug#55420] [PATCH v3 2/2] guix: emacs-utils: Add emacs-header-parse Fredrik Salomonsson
2022-06-17 20:29 ` bug#55420: [PATCH 0/2] Add a function to parse emacs elisp's package header Ludovic Courtès
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