LaTeX-find-matching-{begin,end} and LaTeX-current-environment

[Ikumi Keita]

Hi all,

I have some minor issues with respect to `LaTeX-find-matching-begin',
`LaTeX-find-matching-end' and `LaTeX-current-environment', which I'd
like to discuss.

1. I noticed that `LaTeX-find-matching-{begin,end}' doesn't work
   correctly when the point is just after the asterisk of "\end{foo*}".
   To confirm, put the point at "!" in the following example and
   type M-: (LaTeX-find-matching-begin) RET or M-:
   (LaTeX-find-matching-end) RET
----------------------------------------------------------------------
\documentclass{article}
\begin{document}

\begin{equation*}
  abc = xyz
\end{equation*!}

\end{document}
----------------------------------------------------------------------
   The attached patch fixes the starred variant case, but, as stated in
   the FIXME comment, this simple fix doesn't yet work for the case
   discussed in bug#19281[1]; When the point is after "\bar" of
   "\end{\bar}", neither `LaTeX-find-matching-begin' nor
   `LaTeX-find-matching-end' find the correct position. Should we handle
   such exceptional cases, too?

2. `LaTeX-current-environment' has special support for macrocode*?
   environments, but that support is absent in
   `LaTeX-find-matching-{begin,end}':
----------------------------------------------------------------------
                  ;; macrocode*? in docTeX-mode is special since we
                  ;; have also regular code lines not starting with a
                  ;; comment-prefix.  Hence, the next check just looks
                  ;; if we're inside such a group and returns t to
                  ;; recognize such a situation.
                  (and (eq major-mode 'doctex-mode)
                       (member (match-string-no-properties 2)
                               '("macrocode" "macrocode*"))))
----------------------------------------------------------------------
   Is this intentional? Or should we add similar codes to
   `LaTeX-find-matching-{begin,end}' as well? (I have little experience
   with doctex mode, so am not sure what to do.)

3. The regexp used in `LaTeX-current-environment' is
----------------------------------------------------------------------
                  (re-search-backward
                   "\\\\\\(begin\\|end\\) *{\\([^}]+\\)}" nil t))
----------------------------------------------------------------------
   so it doesn't handle the exceptional cases of bug#19281, namely
   "\begin{\bar{xyz}}" and "\end{\bar{xyz}}". Should we cater for such
   cases?

[1] https://debbugs.gnu.org/cgi/bugreport.cgi?bug=19281

Regards,
Ikumi Keita
#StandWithUkraine #StopWarInUkraine

0001-Support-starred-variant-name.patch
Description: include asterisk