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From: Ihor Radchenko <yantar92@gmail.com>
To: Tim Cross <theophilusx@gmail.com>
Cc: Org-mode <emacs-orgmode@gnu.org>
Subject: Re: org-babel-load-languages usability issue
Date: Fri, 09 Sep 2022 19:25:19 +0800	[thread overview]
Message-ID: <871qsk3i3k.fsf@localhost> (raw)
In-Reply-To: <8635d3nhjf.fsf@gmail.com>

Tim Cross <theophilusx@gmail.com> writes:

>> We have [[info:org#Languages]] linking to
>> https://orgmode.org/worg/org-contrib/babel/languages/index.html
>> I guess we can simply add the manual link to the docstring. Would it be
>> sufficient?
> Yes, I think so. That was what I was thinking would be reasonable and
> would avoid maintenance issues for the doc string when languages are
> added/removed.


>>> Would it load them if the default values for all the languages which
>>> have bundleed modes in Emacs were set to nil rather than t?
>> I am not sure if it is a good idea.
>> I am now looking at the usage of org-babel-load-languages in the code,
>> and I am seeing `org-lint-wrong-header-argument',
>> `org-babel-demarcate-block' ignoring difference between (lang . nil) and
>> (lang .t).
> OK, so if I understand you correctly, not all of org code honours the
> enabled/disabled setting so adding all bundled languages, but setting
> them to nil, would result in unexpected or additional processing for
> those languages despite them being disabled?

Yes, though I am not 100% sure if the impact is significant enough for
us to care.

> If that is the case, you right and adding them would be
> problematic. However, I would also argue this is probably a
> bug. Essentially, it means that the value associated with the language
> symbol key is sometimes interpreted and sometimes ignored. I think this
> is an inconsistency which can potentially cause confusion and could
> contribute to subtle bugs.


> One thing I do wonder though wrt the two examples you cited. Could this
> be deliberate/intentional for these functions?
> I wondering about the scenario where you want to include blocks for a
> certain language, but you do not need to evaluate them, so no need for
> babel support. Might this be a case where you would set the language to
> nil, but be fine with lint and other checks verifying the block
> structure? Provided this isn't also resulting in loading of language
> specific babel code, it may not be an issue?

I do not think that your example is a valid use-case.
(lang . nil), when set during startup, means that (require 'ob-lang) has
never been executed (or, at least, we cannot guarantee it).
When (lang . nil) is changed from (lang . t) at some point,
(require 'ob-lang) is executed, but org-babel-do-load-languages
explicitly unloads the babel function that executes the LANG blocks.

In general, we cannot assume that any of the ob-lang functions are
loaded when there is (lang . nil). No LANG-specific info is available.

Also, (lang . nil) is supposed to deny loading LANG. It should be no
different compared to not listing LANG at all.

Ihor Radchenko,
Org mode contributor,
Learn more about Org mode at https://orgmode.org/.
Support Org development at https://liberapay.com/org-mode,
or support my work at https://liberapay.com/yantar92

  reply	other threads:[~2022-09-09 11:27 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-05  7:23 org-babel-load-languages usability issue Tim Cross
2022-09-05 11:59 ` Ihor Radchenko
2022-09-05 13:11   ` Tim Cross
2022-09-07  4:41     ` Ihor Radchenko
2022-09-07 18:38       ` Tim Cross
2022-09-09 11:25         ` Ihor Radchenko [this message]
2022-09-09 21:56           ` Tim Cross

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