Re: Re: [BUG] beamer export

[Pedro Andres Aranda Gutierrez <paaguti@gmail.com>]

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Hi

CAVEAT EMPTOR: Although it’s some years that I have been using org to create my slides, I never needed this… Interesting to learn new things ;-) 

I personally would not oppose to have a customizable org-frame-environment variable, with its default value being “frame”. 
Then, when actually emitting the code, add something like:

(unless (string= org-frame-environment “frame”
 …)

Which would create the code most of us would expect (i.e. \begin{frame}…\end{frame}) in almost any case except when you really need the `newenvironment’ construct.

My .02 cents, /PA

> El 27 ene 2024, a las 18:00, emacs-orgmode-request@gnu.org escribió:
> 
> Message: 2
> Date: Fri, 26 Jan 2024 20:54:17 +0000
> From: Leo Butler <Leo.Butler@umanitoba.ca <mailto:Leo.Butler@umanitoba.ca>>
> To: Ihor Radchenko <yantar92@posteo.net <mailto:yantar92@posteo.net>>
> Cc: Ihor Radchenko <yantar92@gmail.com <mailto:yantar92@gmail.com>>, Daniel Fleischer
> 	<danflscr@gmail.com <mailto:danflscr@gmail.com>>, Org Mode Mailing List <emacs-orgmode@gnu.org <mailto:emacs-orgmode@gnu.org>>
> Subject: Re: [BUG] beamer export
> Message-ID: <87wmrvlsso.fsf@t14.reltub.ca <mailto:87wmrvlsso.fsf@t14.reltub.ca>>
> Content-Type: text/plain; charset="iso-8859-1"
> 
> On Fri, Jan 26 2024, Ihor Radchenko <yantar92@posteo.net <mailto:yantar92@posteo.net>> wrote:
> 
>> Leo Butler <Leo.Butler@umanitoba.ca <mailto:Leo.Butler@umanitoba.ca>> writes:
>> 
>>>> Apparently, LaTeX has really hard time processing verbatim code inside
>>>> beamer frames.
>>> 
>>> I looked again at the solution here:
>>> https://tex.stackexchange.com/questions/140719/verbatim-in-beamer-showing-error-file-ended-while-scanning-use-of-xverbatim <https://tex.stackexchange.com/questions/140719/verbatim-in-beamer-showing-error-file-ended-while-scanning-use-of-xverbatim>
>>> 
>>> and it errors out with a recent version of pdflatex:
>>> 
>>>   This is pdfTeX, Version 3.141592653-2.6-1.40.25 (TeX Live 2023/Debian) (preloaded format=pdflatex)
>>> 
>>> This is, apparently, a known problem:
>>> 
>>> https://github.com/josephwright/beamer/issues/360 <https://github.com/josephwright/beamer/issues/360>
>>> 
>>> The end of that issue report includes a work-around that we might apply
>>> in org. I have attached a patch for your feedback. The example that
>>> stimulated this discussion compiles with the patch and the testsuite
>>> shows no errors related to it.
>> 
>> Thanks!
>> I have concerns about your approach though.
>> 
>> You are replacing all the frame environments with custom environment
>> unconditionally. However, custom environment has downsides. For example,
>> \againframe will stop working, as pointed earlier in the linked beamer
>> thread
>> https://github.com/josephwright/beamer/issues/360#issuecomment-708705250 <https://github.com/josephwright/beamer/issues/360#issuecomment-708705250>
> 
> The comment that you are citing shows how to define the custom
> environment so that \againframe works correctly. See the attachment
> `beamer-example-againframe.tex' and pdf. You can see that \againframe
> works with the custom environment.
> 
>> 
>> Since the problem appears only when the frame contents contains
>> \end{frame}, it may be sufficient to replace the standard frame
>> environment with the workaround only in such scenario.
> 
> Yes, that might be true. But my feeling is that it would be simpler and
> more robust to use the custom frame environment in most cases.
> 
>> 
>>> +;; Needed to set-up Beamer export.
>>> +(defconst org-beamer--frame-environment
>>> +  (concat "orgframe" (org-id-uuid))
>>> +  "Name of the beamer frame environment.
>>> +This is randomized to prevent collisions.")
>> 
>> Please use constant name. (org-id-uuid) makes export randomized for no
>> good reason.
> 
> There is a good reason to randomize (or at least make customize-able)
> the environment name: so that beamer code generated by ox-beamer can be
> safely inserted into org files and exported by ox-beamer. With a fixed
> name for the environment, we will have just recreated the original
> source of the bug report. As a compromise, in the attached patch, I have
> made the environment name customize-able.
> 
>> 
>>> ;; Install a default set-up for Beamer export.
>>> (unless (assoc "beamer" org-latex-classes)
>>>   (add-to-list 'org-latex-classes
>>> -	       '("beamer"
>>> -		 "\\documentclass[presentation]{beamer}"
>>> +	       `("beamer"
>>> +		 ,(concat "\\documentclass[presentation]{beamer}\n"
>>> +                          ;; Define an alias for the beamer frame environment
>>> +                         "\\newenvironment<>{"
>>> +                         org-beamer--frame-environment
>>> +                         "}[1][]{\\begin{frame}[environment="
>>> +                         org-beamer--frame-environment
>>> +                         ",#1]}{\\end{frame}}")
>> 
>> Please use `org-beamer-template' rather than modifying the class.
>> Modifying the class may confuse users.
> 
> Ok, I have done so.
> 
> The docstring of `org-latex-classes' says:
> 
>    The HEADER-STRING is the header that will be inserted into the
>    LaTeX file.  It should contain the \documentclass macro, and
>    anything else that is needed for this setup.
> 
>> From that, I figured that would be the correct place to put that
> \newenvironment command. I have moved it, as requested.
> 
> Please see the revised patch. I believe that I have taken into account
> your suggestions.
> 
> Leo


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