[PATCH] ox-latex.el --- CUSTOM_ID-as-section-label-in-latex-export

[PATCH] ox-latex.el --- CUSTOM_ID-as-section-label-in-latex-export

[Eric Schulte]

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From c087e84a8fd80b277bf064eb31f1b893c25f1b4a Mon Sep 17 00:00:00 2001
From: Eric Schulte <schulte.eric@gmail.com>
Date: Mon, 24 Jun 2013 10:25:03 -0600
Subject: [PATCH] CUSTOM_ID as section label in latex export

  When exporting to HTML, custom ids of headlines become references to
  the resulting section in the exported document.  This is both more
  stable and more readable than using section numbers.  This commit adds
  this option to the latex exporter.

* lisp/ox-latex.el (org-latex-headline): If headlines have the CUSTOM_ID
  property set, then this value is used as the label instead of the
  section number.
---
 lisp/ox-latex.el | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/lisp/ox-latex.el b/lisp/ox-latex.el
index f2c6261..68b43e1 100644
--- a/lisp/ox-latex.el
+++ b/lisp/ox-latex.el
@@ -1399,10 +1399,15 @@ holding contextual information."
 			       todo todo-type priority text tags))
 	   ;; Associate \label to the headline for internal links.
 	   (headline-label
-	    (format "\\label{sec-%s}\n"
-		    (mapconcat 'number-to-string
-			       (org-export-get-headline-number headline info)
-			       "-")))
+	    ;; Optionally use the custom-id instead of section number
+	    (if (org-element-property :CUSTOM_ID headline)
+		(format "\\label{%s}\n"
+			(org-element-property :CUSTOM_ID headline))
+	      (format "\\label{sec-%s}\n"
+		      (mapconcat
+		       'number-to-string
+		       (org-export-get-headline-number headline info)
+		       "-"))))
 	   (pre-blanks
 	    (make-string (org-element-property :pre-blank headline) 10)))
       (if (or (not section-fmt) (org-export-low-level-p headline info))
-- 
1.8.3.1


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-- 
Eric Schulte
http://cs.unm.edu/~eschulte

Re: [PATCH] ox-latex.el --- CUSTOM_ID-as-section-label-in-latex-export

[Nicolas Goaziou]

Hello,

Eric Schulte <schulte.eric@gmail.com> writes:

> From c087e84a8fd80b277bf064eb31f1b893c25f1b4a Mon Sep 17 00:00:00 2001
> From: Eric Schulte <schulte.eric@gmail.com>
> Date: Mon, 24 Jun 2013 10:25:03 -0600
> Subject: [PATCH] CUSTOM_ID as section label in latex export
>
>   When exporting to HTML, custom ids of headlines become references to
>   the resulting section in the exported document.  This is both more
>   stable and more readable than using section numbers.  This commit adds
>   this option to the latex exporter.

Thanks for the patch.

Though, it isn't as stable as relying on section numbers: there is no
guarantee the custom id will be unique nor that it will not contain any
forbidden character.

This patch also breaks cross references, which expects labels to be
built from section number (see `org-latex-link').

Since you (almost?) never need to write \ref{custom-id} in the Org
buffer, I don't think it is bad to keep current label system.

Another option would be to have both \label{sec-...} and
\label{custom-id}. But it would require the user to check validity of
its id.


Regards,

-- 
Nicolas Goaziou

Re: [PATCH] ox-latex.el --- CUSTOM_ID-as-section-label-in-latex-export

[Eric Schulte]

Nicolas Goaziou <n.goaziou@gmail.com> writes:

> Hello,
>
> Eric Schulte <schulte.eric@gmail.com> writes:
>
>> From c087e84a8fd80b277bf064eb31f1b893c25f1b4a Mon Sep 17 00:00:00 2001
>> From: Eric Schulte <schulte.eric@gmail.com>
>> Date: Mon, 24 Jun 2013 10:25:03 -0600
>> Subject: [PATCH] CUSTOM_ID as section label in latex export
>>
>>   When exporting to HTML, custom ids of headlines become references to
>>   the resulting section in the exported document.  This is both more
>>   stable and more readable than using section numbers.  This commit adds
>>   this option to the latex exporter.
>
> Thanks for the patch.
>
> Though, it isn't as stable as relying on section numbers: there is no
> guarantee the custom id will be unique nor that it will not contain any
> forbidden character.
>
> This patch also breaks cross references, which expects labels to be
> built from section number (see `org-latex-link').
>

Oh, I see now that I can simply use [[#id]] links and they will be
translated as appropriate.  This will then also resolve these references
if I export the paper to HTML.

Thanks for the explanation,

>
> Since you (almost?) never need to write \ref{custom-id} in the Org
> buffer, I don't think it is bad to keep current label system.
>
> Another option would be to have both \label{sec-...} and
> \label{custom-id}. But it would require the user to check validity of
> its id.
>
>
> Regards,

-- 
Eric Schulte
http://cs.unm.edu/~eschulte