[AUCTeX-devel] Extending `LaTeX-array-count-columns'

[Arash Esbati]

Hi all,

2 thing occurred to me when hitting `M-RET' in tabular environments:
Current code in `LaTeX-array-count-columns' cannot handle multi column
specs like `*{num}{spec}' and optional args to column specs S and s from
siunitx.el.  I have a patch to handle both issues.  Can people please
test this code against their tabular's and see if it does the right
thing?  My test file is:

--8<---------------cut here---------------start------------->8---
\documentclass{article}

\usepackage{siunitx}
\usepackage{array}
\usepackage{tabularx}
\newcolumntype{Y}{>{\tiny\scshape}r}

\begin{document}

Eval first:
\begin{verbatim}
(defun LaTeX-array-count-columns (start end)
  "Count number of ampersands to be inserted.
The columns are specified by the letters found in the string
`LaTeX-array-column-letters' and the number of those letters within the
text between START and END is basically considered to be the number of
columns.  The arguments surrounded between braces such as p{30pt} do not
interfere the count of columns.

Return one less number than the columns, or nil on failing to count the
right number."
  (save-excursion
    (let (p (cols 0))
      (goto-char start)
      (while (< (setq p (point)) end)

        ;; The below block accounts for one unit of move for
        ;; one column.
        (setq cols (+ cols
                      (if (looking-at-p "\\*[ \t\r\n%]*{[ \t\r\n%0-9]+}")
                          (progn
                            (re-search-forward
                             "\\*[ \t\r\n%]*{[ \t\r\n%]*\\([0-9]+\\)[ 
\t\r\n%]*}" end t)
                            (string-to-number (match-string-no-properties 1)))
                        (skip-chars-forward
                         LaTeX-array-column-letters end))))
        (skip-chars-forward (concat
                             "^" LaTeX-array-column-letters "*"
                             TeX-grop LaTeX-optop) end)
        (when (or (eq (following-char) ?\{)
                  (eq (following-char) ?\[))
          (forward-list 1))

        ;; Not sure whether this is really necessary or not, but
        ;; prepare for possible infinite loop anyway.
        (when (eq p (point))
          (setq cols nil)
          (goto-char end)))
      ;; The number of ampersands is one less than column.
      (if cols (1- cols)))))
\end{verbatim}

Standard procedure:
\begin{tabular}[t]{*{4}{l}l}
  1 & 2 & 3 & 4 & 5 \\
    &&&&
\end{tabular}

Add some commands before cells:
\begin{tabular}[b]{*{4}{>{\scriptsize}l}>{\huge}l}
  1 & 2 & 3 & 4 & 5 \\
    &&&&
\end{tabular}

\begin{tabular}{*{4}{>{\scriptsize}l} |l|}
  1 & 2 & 3 & 4 & 5 \\
    &&&&
\end{tabular}

Custom column spec `Y':
\begin{tabular}[t]{* { 2 } {>{\scriptsize}l} | Y | * { 2 } {r}}
  1 & 2 & 3 & 4 & 5 \\
    &&&&
\end{tabular}

Eval first for `siunitx.el':
\begin{verbatim}
(set (make-local-variable 'LaTeX-array-column-letters)
     (concat LaTeX-array-column-letters "sS"))
\end{verbatim}

Ignore optional `[...]' after S and s:
\begin{tabular}{
  s
  S[table-number-alignment = center]
  s[table-number-alignment = left]
  S[table-number-alignment = right]
  }
  {Some Values} & {Some Values} & {Some Values} & {Some Values} \\
                &&&
\end{tabular}

\begin{tabular}{%
  S[table-format = 1.1e1]
  S[fixed-exponent = 3 ,
    table-format = 2.1 ,
    table-omit-exponent ] }
  1 & 2 \\
    &
\end{tabular}
\end{document}
--8<---------------cut here---------------end--------------->8---

Any comments welcome.

Best, Arash