Re: [O] [patch] Support CUSTOM_ID property in latex export

[Richard Lawrence]

Nicolas Goaziou <address@hidden> writes:

> Richard Lawrence <address@hidden> writes:
>
>> Here is a patch to add support for using CUSTOM_ID properties for labels
>> and refs in the LaTeX exporter.
>
> Thank you for the patch. Though, I don't understand why it is needed.
>
>> I also need this behavior, which is why I wrote this.
>
> Would you mind explaining your use case?
>
> From a user's perspective, CUSTOM_ID allows an user to refer to
> a particular headline with a specific internal link type. How this is
> done internally is something different, which belong to the
> implementation level.

Sure.  I apologize -- I should have said more about this in my previous
email than just referring to that old post.

I am presently using Org to write my dissertation, which I compile using
the LaTeX exporter.  This means I am writing long documents with
embedded LaTeX blocks.  (Maybe this is ill-advised, but it has worked
great so far!)

Basically, I want control over how the labeling is done in the exported
document for two reasons:

1) Sometimes I need to refer to a section from within an embedded LaTeX
block.  In that case, I need to know the appropriate label to use at the
LaTeX level, not just in Org.  For example:

* A headline
  :PROPERTIES:
  :CUSTOM_ID: sec:a-headline
  :END:

# ... stuff ...

#+BEGIN_LATEX
% ... more stuff ...
(see section~\ref{sec:a-headline})
#+END_LATEX

This is not possible with the present section labeling in LaTeX export,
because I have no way of forcing Org to use a particular label for a
section.

2) I hope this doesn't happen, but there may come a time when I need to
move away from Org and just use straight LaTeX.  Having control over the
labeling will make this transition much easier, because it means I won't
have to worry about manually changing the labels in a long document from
Org's default "sec-..." numbering to my own semantic labels.

Right now, I am at a risk of losing a lot of information if I have to
make this transition, because my CUSTOM_ID values don't have any effect
on the generated LaTeX.  Being able to set section labels as needed from
within Org would reduce this risk and therefore allow me to put this
transition off longer.

Another reason (not mine, but someone else might care) is:

3) This will make the LaTeX exporter's behavior more consistent with the
HTML exporter's behavior.  The HTML exporter will use CUSTOM_ID if it is
supplied to construct the id attributes of headlines and divs.  If
someone is relying on this behavior of the HTML exporter, they might be
unpleasantly surprised by the LaTeX exporter's behavior.

Does all that seem reasonable?
  
Best,
Richard