Re: Bug: Problem with LaTeX export, footnotes in table headers, and longtabu [8.3.4 (8.3.4-31-gcb683e-elpa @ /home/berhol/.emacs.d/elpa/org-20160404/)]

[Berthold Hoellmann <berthold.hoellmann@dnvgl.com>]

Nicolas Goaziou <mail@nicolasgoaziou.fr> writes:

> Hello,
>
> Berthold Höllmann <berthold.hoellmann@dnvgl.com> writes:
>
>> I am exporting a large table from org to pdf via LaTeX. The meaning of
>> some of the column headers are to be explained in footnotes. The table
>> spans more than one page, so continuation headers are generated using
>> longtabu. These continuation headers mangle with the footnote numbering
>> as can be seen in this example:
>>
>> # -*- mode: org -*-
>> #+STARTUP: showall
>> #+LaTeX_CLASS_OPTIONS: [a5paper]
>> #+LATEX_HEADER: \usepackage[T1]{fontenc}
>> #+LATEX_HEADER: \usepackage[utf8x]{inputenc}
>> #+LATEX_HEADER: \usepackage{tabu}
>> #+TITLE: Multi page table test
>>
>> * Multi page table
>>
>>   #+ATTR_LATEX: :environment longtabu
>>   | *Typ[fn:test]* |
>>   |----------------|
>>   |              1 |
>>   |              2 |
>>   |              3 |
>>   |              4 |
>>   |              5 |
>>   |              6 |
>>   |    7[fn:test2] |
>>   |              8 |
>>   |              9 |
>>   |             10 |
>>   |----------------|
>>
>> * Footnotes
>>
>> [fn:test]
>>   Testing footnotes with multi page latex tables.
>>
>> [fn:test2]
>>   Another Test
>
> [...]
>
>> \section{Multi page table}
>> \label{sec:orgheadline1}
>>
>> \begin{longtabu}{r}
>> \textbf{Typ\footnotemark}\\
>> \hline
>> \endfirsthead
>> \multicolumn{1}{l}{Continued from previous page} \\
>> \hline
>>
>> \textbf{Typ\footnotemark} \\
>>
>> \hline
>> \endhead
>> \hline\multicolumn{1}{r}{Continued on next page} \\
>> \endfoot
>> \endlastfoot
>> \hline
>> 1\\
>> 2\\
>> 3\\
>> 4\\
>> 5\\
>> 6\\
>> 7\footnotemark\\
>> 8\\
>> 9\\
>> 10\\
>> \hline
>> \end{longtabu}
>> \footnotetext[1]{Testing footnotes with multi page latex tables.}\footnotetext[2]{Another Test}
>> \end{document}
>>
>>
>>
>> [fn:test] becomes [1] in the first, and [2] in the continuation headers,
>> but [2] links to the content of [fn:test2], which becomes a reference
>> without target.
>
> Isn't it a LaTeX limitation? IIRC, footnotes support in tables is
> somewhat flaky. Anyway, if you think it is Org's fault, do you know the
> LaTeX code that should be produced in this case?
>

Actually I was able to patch `org-latex-footnote-reference' to get the
results I line. The trick is to add the counter number given at the
\footnotetext command to the \footnotemark command also:

(defun org-latex-footnote-reference (footnote-reference contents info)
  "Transcode a FOOTNOTE-REFERENCE element from Org to LaTeX.
CONTENTS is nil.  INFO is a plist holding contextual information."
  (concat
   ;; Insert separator between two footnotes in a row.
   (let ((prev (org-export-get-previous-element footnote-reference info)))
     (when (eq (org-element-type prev) 'footnote-reference)
       (plist-get info :latex-footnote-separator)))
   (cond
    ;; Use \footnotemark if the footnote has already been defined.
    ((not (org-export-footnote-first-reference-p footnote-reference info))
     (format "\\footnotemark[%s]{}"
             (org-export-get-footnote-number footnote-reference info)))
    ;; Use \footnotemark if reference is within another footnote
    ;; reference, footnote definition or table cell.
    ((org-element-lineage footnote-reference
                          '(footnote-reference footnote-definition table-cell))
     (format "\\footnotemark[%s]{}"
             (org-export-get-footnote-number footnote-reference info)))
    ;; Otherwise, define it with \footnote command.
    (t
     (let ((def (org-export-get-footnote-definition footnote-reference info)))
       (concat
        (format "\\footnote{%s}" (org-trim (org-export-data def info)))
        ;; Retrieve all footnote references within the footnote and
        ;; add their definition after it, since LaTeX doesn't support
        ;; them inside.
        (org-latex--delayed-footnotes-definitions def info)))))))


Best regards

Berthold Höllmann
--
Development Eng. - Structural Methods, Information Management Research & Development, Hamburg


E-mail berthold.hoellmann@dnvgl.com
Direct +49 40 36149 7374

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