Help with fixing an org-mode multicolumn implementation - LaTeX special characters

Help with fixing an org-mode multicolumn implementation - LaTeX special characters

[mcg]

I found a very nice implementation of LaTeX multicolumn functionality in 
this thread:
https://lists.gnu.org/archive/html/emacs-orgmode/2013-02/msg00736.html
("using export filters to emulate multi-column table cells?")

#+begin_src emacs-lisp :exports none
(defun my-latex-multicolumn-filter (row backend info)
   (when (org-export-derived-backend-p backend 'latex)
     (while (string-match
"\\(<\\([0-9]+\\)col\\([lrc]\\)?>[[:blank:]]*\\([^&]+\\)\\)" row)
       (let ((columns (string-to-number (match-string 2 row)))
             (start (match-end 0))
             (contents (replace-regexp-in-string "[[:blank:]]*$" ""
(match-string 4 row)))
             (algn (or (match-string 3 row) "l")))
         (setq row (replace-match
                    (format "\\\\multicolumn{%d}{%s}{%s}" columns algn 
contents)
nil nil row 1))
         (while (and (> columns 1) (string-match "&" row start))
           (setq row (replace-match "" nil nil row))
           (decf columns))))
     row))
(add-to-list 'org-export-filter-table-row-functions
'my-latex-multicolumn-filter)
#+end_src

#+LATEX_HEADER: \usepackage{multirow}

You have to put the number of columns to span and a r / l / c option for 
column alignment (<2colc>) and the column contents afterwards. Nice!

#+CAPTION: Example table
| Characters not working        | <2colc> Characters working: ! " § . , 
* + ? % |                  |
|-------------------------------+-----------------------------------------------+------------------|
| ^ % _ { } $                   | The header above is 
merged                    | over two columns |
| /italics/ *bold* _underline_ 
|                                               |                  |
| any, \LaTeX special character 
|                                               |                  |
| or expression requiring \ 
|                                               |                  |

However, using any of the characters of the left column of my example 
table in the merged <2colc> column, I get:
"setq: Invalid use of `\' in replacement text"


Questions:
- How to escape the special characters in the left column properly to be 
able to use them? (tried everything I could think of)
or
- How to modify the code above so that it allows for such characters.

- If anyone likes the implementation and is more capable than I am, then 
the same for multirow would be really nice...

Comment: whoever read some of my questions recently will notice that I 
excessively use org-mode as a LaTeX frontend.  I am aware that this is 
not what it is supposed to be in the first place - but it works so 
perfect 99 % of the time, so I cannot keep from asking...

Re: Help with fixing an org-mode multicolumn implementation - LaTeX special characters

[Aaron Ecay]

Hi mcg,

2016ko otsailak 21an, mcg-ek idatzi zuen:
> 
> I found a very nice implementation of LaTeX multicolumn functionality in 
> this thread:
> https://lists.gnu.org/archive/html/emacs-orgmode/2013-02/msg00736.html

[...]

> However, using any of the characters of the left column of my example 
> table in the merged <2colc> column, I get:
> "setq: Invalid use of `\' in replacement text"

I think the function should be written (untested):

(defun my-latex-multicolumn-filter (row backend info)
  (when (org-export-derived-backend-p backend 'latex)
    (while (string-match "\\(<\\([0-9]+\\)col\\([lrc]\\)?>[[:blank:]]*\\([^&]+\\)\\)" row)
      (let ((columns (string-to-number (match-string 2 row)))
            (start (match-end 0))
            (contents (replace-regexp-in-string "[[:blank:]]*$" "" (match-string 4 row)))
            (algn (or (match-string 3 row) "l")))
        (setq row (replace-match
                   (format "\\multicolumn{%d}{%s}{%s}" columns algn contents)
                   nil t row 1))
        (while (and (> columns 1) (string-match "&" row start))
          (setq row (replace-match "" nil nil row))
          (decf columns))))
    row))

The change is setting the third argument (‘literal’) to ‘replace-match’
to t, and deleting an extra backslash in the "\\multicolumn..." string.

> 
> 
> Questions:
> - How to escape the special characters in the left column properly to be 
> able to use them? (tried everything I could think of)
> or
> - How to modify the code above so that it allows for such characters.
> 
> - If anyone likes the implementation and is more capable than I am, then 
> the same for multirow would be really nice...

Unfortunately I think that’s more complicated, since it would necessitate
examining/modifying the whole table in one go, rather than operating one
row at a time.

-- 
Aaron Ecay

Re: Help with fixing an org-mode multicolumn implementation - LaTeX special characters

[mcg]

Hello Aaron,
[I noticed I did not answer to the list; just writing again to add it to 
the list]

this fix works perfect!  Thank you very much.
Never mind about multirow...

Michael


On 22/02/16 16:48, Aaron Ecay wrote:
> Hi mcg,
>
> 2016ko otsailak 21an, mcg-ek idatzi zuen:
>> I found a very nice implementation of LaTeX multicolumn functionality in
>> this thread:
>> https://lists.gnu.org/archive/html/emacs-orgmode/2013-02/msg00736.html
> [...]
>
>> However, using any of the characters of the left column of my example
>> table in the merged <2colc> column, I get:
>> "setq: Invalid use of `\' in replacement text"
> I think the function should be written (untested):
>
> (defun my-latex-multicolumn-filter (row backend info)
>    (when (org-export-derived-backend-p backend 'latex)
>      (while (string-match "\\(<\\([0-9]+\\)col\\([lrc]\\)?>[[:blank:]]*\\([^&]+\\)\\)" row)
>        (let ((columns (string-to-number (match-string 2 row)))
>              (start (match-end 0))
>              (contents (replace-regexp-in-string "[[:blank:]]*$" "" (match-string 4 row)))
>              (algn (or (match-string 3 row) "l")))
>          (setq row (replace-match
>                     (format "\\multicolumn{%d}{%s}{%s}" columns algn contents)
>                     nil t row 1))
>          (while (and (> columns 1) (string-match "&" row start))
>            (setq row (replace-match "" nil nil row))
>            (decf columns))))
>      row))
>
> The change is setting the third argument (‘literal’) to ‘replace-match’
> to t, and deleting an extra backslash in the "\\multicolumn..." string.
>
>>
>> Questions:
>> - How to escape the special characters in the left column properly to be
>> able to use them? (tried everything I could think of)
>> or
>> - How to modify the code above so that it allows for such characters.
>>
>> - If anyone likes the implementation and is more capable than I am, then
>> the same for multirow would be really nice...
> Unfortunately I think that’s more complicated, since it would necessitate
> examining/modifying the whole table in one go, rather than operating one
> row at a time.
>