Re: [babel] eval code only once :eval once

["Sebastien Vauban" <wxhgmqzgwmuf-geNee64TY+gS+FvcfC7Uqw@public.gmane.org>]

Hi Thomas,

Thomas S. Dye wrote:
> Torsten Wagner <torsten.wagner-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> writes:
>> I started to use lisp (as well as other) code blocks more and more to
>> modify my work environment (emacs) for a particular (buffer-based)
>> task.
>> That is I change some variables, add some stuff etc.
>> A real world example is for example the section below
>>
>> * Set-up							  :nonexport:
>> #+source: setup-minted
>> #+begin_src emacs-lisp :exports none :results silent
>>     (setq org-export-latex-listings 'minted)
>>     (setq org-export-latex-custom-lang-environments
>>           '(
>>            (emacs-lisp "common-lispcode")
>>             ))
>>     (setq org-export-latex-minted-options
>>           '(("frame" "lines")
>>             ("fontsize" "\\scriptsize")
>>             ("linenos" "")))
>>     (setq org-latex-to-pdf-process
>>           '("pdflatex -shell-escape -interaction nonstopmode
>> -output-directory %o %f"
>>             "pdflatex -shell-escape -interaction nonstopmode
>> -output-directory %o %f"
>>             "pdflatex -shell-escape -interaction nonstopmode
>> -output-directory %o %f"))
>> #+end_src
>>
>> This are settings from worg, which I use only during my work on that
>> particular file/buffer e.g. to modify the export of the following
>> beamer presentation.
>> Whenever I load the buffer I jump to set-up and hit C-c C-C to execute
>> it once. After that exports will do what I want.
>> If I would change the above to :exports results and :results silent I
>> would be asked to execute the code block on every export.
>> Thanks to the new auto completion feature, I came across :eval and
>> wonder if it makes sense to add
>> :eval once
>> and
>> :eval once-query
>>
>> Which would allow to execute it only once (with query) if not called
>> before and otherwise keeps quite.
>> That would make *Set-up blocks much more efficient.
>> Was thinking why there is no 'no-query' resp. 'always' flag which
>> would execute code blocks without query even if asked for it in
>> general but that would be somehow against safety measures ;)
>
> Aloha Totti,
>
> Will :cache yes do what you want?

I'd answer no, as this wouldn't be re-eval'ed the next time he opens that
buffer.

But...?

Best regards,
  Seb

-- 
Sebastien Vauban