[O] multicolumn cells in latex export

[Vikas Rawal]

Two years ago, Eric Schulte had shared some most useful code snippets (https://lists.gnu.org/archive/html/emacs-orgmode/2014-08/msg00113.html). This included an export filter (code pasted below) that provided a very useful way of introducing multicolumn cells in latex export.

I have been using this since then without any trouble. But today I tried using it to centre-align column headings in the top row by using <1colc>. While it works for other columns, it does not work on the last column. 

The last column gets exported as 

\multicolumn{1}{c}{Australia (2015)\\

}\hline

rather than as

\multicolumn{1}{c}{Australia (2015)}\\

\hline

Can anyone help debug what is wrong with this code?

Vikas

---------------

;;; Multi-column Table Cells

;;

;; Export table cells with multiple columns using Latex-like syntax.

;; For example in the following the "<3colc>Backends" cell spans 3

;; columns with it's text centered.

;;

;; |           | <3colc>Backends |       |       |

;; |           |           LaTeX |  HTML |  Text |

;; |-----------+-----------------+-------+-------|

;; | extension |            .tex | .html | .txt  |

;;

;; The `org-export-multicolumn-filter-latex' function is taken from

;; the following.

;; http://thread.gmane.org/gmane.emacs.orgmode/66332/match=latex+table+multicolumn+cell

(defun org-export-multicolumn-filter (row backend info)

  (cond

   ((org-export-derived-backend-p backend 'latex)

    (org-export-multicolumn-filter-latex row backend info))

   ((org-export-derived-backend-p backend 'html)

    (org-export-multicolumn-filter-html row backend info))))

(defun org-export-multicolumn-filter-latex (row backend info)

  (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

                     "\\\\" "\\\\\\\\"

                     (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)

(defun org-export-multicolumn-filter-html (row backend info)

  (while (string-match "class=\".*\" *>&lt;\\([0-9]+\\)col\\([lrc]\\)?&gt;" row)

    (let ((columns (string-to-number (match-string 1 row)))

          (start (match-end 0))

          (algn (case (intern (or (match-string 2 row) "l"))

                  (c "center")

                  (r "right")

                  (l "left"))))

      (setq row (replace-match

                 (format " class=\"%s\" colspan=\"%s\">" algn columns)

                 nil nil row))

      (while (and (> columns 1)

                  (string-match "<th .*>&#xa0;</th>" row start))

        (setq row (replace-match "" nil nil row))

        (decf columns))))

  row)

(add-to-list 'org-export-filter-table-row-functions

             'org-export-multicolumn-filter)