Ah, I see. However, tried this in the scratch buffer:
(let ((str
"\\documentclass[11pt]{article}\n\n\n\\usepackage[utf8]{inputenc}
\\usepackage[french]{babel}\n"))
(if (string-match "\\\\usepackage\\[\\([^]]*\\)\\]{babel}" str)
(message (match-string 1 str))
(message "???")))
Ad it printed
french
So, apparently, you don't need the extra escape inside the charset,
\\([^]]*\\)
should be enough...
Cheers, /PA
On Fri, 22 May 2026 at 04:31, Derek Chen-Becker <[email protected]>
wrote:
> Hi Pedro,
>
> Thanks, I did try the non-greedy capture and it didn't work. I'm actually
> just realizing that it probably didn't work because it's not that it's
> greedy, it's that "]{babel}"doesn't sufficiently constrain the contents
> ahead of it.
>
> Cheers,
>
> Derek
>
>
>
> On Thu, May 21, 2026 at 9:30 AM Pedro Andres Aranda Gutierrez <
> [email protected]> wrote:
>
>> Hi Derek,
>>
>> the ox-latex.el part can be simplified as
>>
>> (not (string-match "\\\\usepackage\\[\\(.*?\\)\\]{babel}" header)))
>>
>> That will make the regex stop before the ']' and is easier to read (at
>> least for me-TM),
>>
>> Best,
>> /PA
>> ox-latex.el maintainer
>>
>>
>> On Thu, 21 May 2026 at 15:30, Derek Chen-Becker <[email protected]>
>> wrote:
>>
>>> Confirmed, against d34e34f3e.
>>>
>>> The replacement text of "utf8]{inputenc} \\usepackage[french, english"
>>> makes it appear that the regex patterns used in
>>> `org-latex-guess-babel-language' aren't sufficiently constrained. Checking
>>> the regex, it's using "\\[.*\\]", which is why you're only seeing this when
>>> you have more than one extra header (with only one, there's only one set of
>>> braces).
>>>
>>> I took a look and think I have a fix but I want a second opinion. The
>>> attached patch fixes the regex by changing the greedy match for the
>>> language to one that only captures what's between the "[...]". I tried
>>> using a non-greedy qualifier (".*?") and that didn't work, but I feel like
>>> I always get tripped up by Elisp regex patterns. If someone has a better
>>> suggestion for the regex I'm open to changing it.
>>>
>>> Owned.
>>>
>>> Cheers,
>>>
>>> Derek
>>>
>>> On Wed, May 20, 2026 at 11:41 AM <[email protected]> wrote:
>>>
>>>>
>>>> With the following Org file
>>>>
>>>> ----------------------
>>>> #
>>>> * subtree
>>>> :PROPERTIES:
>>>> :EXPORT_LATEX_HEADER: \usepackage[utf8]{inputenc}
>>>> :EXPORT_LATEX_HEADER+: \usepackage[french]{babel}
>>>> :END:
>>>>
>>>> bak
>>>> ----------------------
>>>>
>>>> upon subtree export (C-c C-e C-s lp), I get an error, the beginning of
>>>> the
>>>> backtrace of which is
>>>>
>>>> Debugger entered--Lisp error: (error "Invalid use of ‘\\’ in replacement
>>>> text")
>>>>
>>>> org-latex-guess-babel-language("\\documentclass[11pt]{article}\n\n\n\\usepackage[utf8]{inputenc}
>>>> \\usepackage[french]{babel}\n" (:export-options (subtree) :back-end
>>>> #s(org-export-backend :name latex :parent nil :transcoders (... ...
>>>> ... .
>>>>
>>>>
>>>> This occurs with
>>>>
>>>> GNU Emacs 30.2 (build 1, x86_64-redhat-linux-gnu, GTK+ Version 3.24.43,
>>>> cairo version 1.18.2) of 2025-08-18
>>>>
>>>> with either
>>>>
>>>> - a void .emacs and
>>>>
>>>> Org mode version 9.8.4 (9.8.4-2f6959 @
>>>> /home/cochard/.emacs.d/elpa/org-9.8.2/)
>>>>
>>>> - a void .emacs and
>>>>
>>>> Org mode version 9.8.2 (9.8.2-2ef390 @
>>>> /home/cochard/.emacs.d/elpa/org-9.8.2/)
>>>>
>>>> - emacs -Q and
>>>>
>>>> Org mode version 9.7.11 (release_9.7.11 @
>>>> /usr/share/emacs/30.2/lisp/org/)
>>>>
>>>> For what it's worth: (1) the problem does not show up for every
>>>> combination
>>>> of
>>>>
>>>> :EXPORT_LATEX_HEADER:
>>>> :EXPORT_LATEX_HEADER+:
>>>>
>>>> (2) I did not succeed in exhibiting the problem with a single
>>>>
>>>> :EXPORT_LATEX_HEADER:
>>>>
>>>> --
>>>> EOST (École et Observatoire des Sciences de la Terre)
>>>> ITE (Institut Terre & Environnement) | [email protected]
>>>> 5 rue René Descartes | Phone: +33 (0)3 68 85 50 44
>>>> F-67084 Strasbourg Cedex, France | bureau 110, ancien bât.
>>>>
>>>>
>>>
>>> --
>>> +---------------------------------------------------------------+
>>> | Derek Chen-Becker |
>>> | GPG Key available at https://keybase.io/dchenbecker and |
>>> | https://pgp.mit.edu/pks/lookup?search=derek%40chen-becker.org |
>>> | Fngrprnt: EB8A 6480 F0A3 C8EB C1E7 7F42 AFC5 AFEE 96E4 6ACC |
>>> +---------------------------------------------------------------+
>>>
>>>
>>
>> --
>> Fragen sind nicht da, um beantwortet zu werden,
>> Fragen sind da um gestellt zu werden
>> Georg Kreisler
>>
>> "Sagen's Paradeiser" (ORF: Als Radiohören gefährlich war) => write BE!
>> Year 2 of the New Koprocracy
>>
>>
>
> --
> +---------------------------------------------------------------+
> | Derek Chen-Becker |
> | GPG Key available at https://keybase.io/dchenbecker and |
> | https://pgp.mit.edu/pks/lookup?search=derek%40chen-becker.org |
> | Fngrprnt: EB8A 6480 F0A3 C8EB C1E7 7F42 AFC5 AFEE 96E4 6ACC |
> +---------------------------------------------------------------+
>
>
--
Fragen sind nicht da, um beantwortet zu werden,
Fragen sind da um gestellt zu werden
Georg Kreisler
"Sagen's Paradeiser" (ORF: Als Radiohören gefährlich war) => write BE!
Year 2 of the New Koprocracy
