loss of text properties in org-export--generate-copy-script

loss of text properties in org-export--generate-copy-script

[John Kitchin]

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In the function org-export--generate-copy-script, the buffer contents are
copied over with buffer-substring-no-properties, so it appears that all
text properties are lost in the temporary copy.

I wondered why that is done?

I came across this because I was using text properties to find pieces of
text to modify before exporting in a org-export-before hook, but it doesn't
work since the text properties are gone.

The text properties are put on by font-lock. Curiously, if I add these
three lines

  (switch-to-buffer (current-buffer))
  (sem-mode 1)  # refontifies buffer
  (message-box "")

then the text-properties are put back on and I can find them again. If
leave the first or last line off though, this does not work. The last line
is especially mystifying.

Here is a minimal example that shows the issue. When you run the src block,
the word red will be italicized, and when you export it red will be turned
into the word yellow. without the unintuitive switch-to-buffer and message
box lines though, you will get an error.

Any ideas on what is happening here?

# begin
This is red.


#+BEGIN_SRC emacs-lisp :results silent :exports none
(font-lock-add-keywords
 nil
 '(("red" 0 '(face italic changeme t))))


(defun preprocess (backend)
  (switch-to-buffer (current-buffer))
  (font-lock-add-keywords
   nil
   '(("red" 0 '(face italic changeme t))))
  (message-box "")
  (let* ((start (next-single-property-change (point) 'changeme))
(end (next-single-property-change start 'changeme)))
    (setf (buffer-substring start end) "yellow")))

(add-hook 'org-export-before-processing-hook 'preprocess nil t)
#+END_SRC

John

-----------------------------------
Professor John Kitchin
Doherty Hall A207F
Department of Chemical Engineering
Carnegie Mellon University
Pittsburgh, PA 15213
412-268-7803
@johnkitchin
http://kitchingroup.cheme.cmu.edu

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Re: loss of text properties in org-export--generate-copy-script

[Nicolas Goaziou]

Hello,

John Kitchin <jkitchin@andrew.cmu.edu> writes:

> In the function org-export--generate-copy-script, the buffer contents are
> copied over with buffer-substring-no-properties, so it appears that all
> text properties are lost in the temporary copy.
>
> I wondered why that is done?

I feel more comfortable when I can assume no text property will get in
the way.

I turned `buffer-substring-no-properties' into `buffer-string' in
"master".

Regards,

-- 
Nicolas Goaziou

Re: loss of text properties in org-export--generate-copy-script

[John Kitchin]

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ok. I thought there might be a reason. I guess something like a read-only
property could be a problem if anything tries to change those. Are there
other properties you know of that could be problematic? maybe before/after
change properties? I think there are inhibit-* variables to avoid issues
with those if they become a problem.

I am still baffled on why the unusual workaround with message-box makes it
work though.

John

-----------------------------------
Professor John Kitchin
Doherty Hall A207F
Department of Chemical Engineering
Carnegie Mellon University
Pittsburgh, PA 15213
412-268-7803
@johnkitchin
http://kitchingroup.cheme.cmu.edu



On Tue, Nov 27, 2018 at 5:49 PM Nicolas Goaziou <mail@nicolasgoaziou.fr>
wrote:

> Hello,
>
> John Kitchin <jkitchin@andrew.cmu.edu> writes:
>
> > In the function org-export--generate-copy-script, the buffer contents are
> > copied over with buffer-substring-no-properties, so it appears that all
> > text properties are lost in the temporary copy.
> >
> > I wondered why that is done?
>
> I feel more comfortable when I can assume no text property will get in
> the way.
>
> I turned `buffer-substring-no-properties' into `buffer-string' in
> "master".
>
> Regards,
>
> --
> Nicolas Goaziou
>

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