[O] Force center alignment in LaTeX table export?

[Phil Regier]

Apologies in advance if this has been discussed already; I lost track of the list for a while.

That said, since updating to ELPA org-20170210, I can no longer (I'm pretty sure this was working previously but I can't prove it -- maybe my document was broken and I just didn't notice) use \columncolor{red} in the :align argument to #+latex+attr: for tables any more; this gets changed to \cocumncococ{ced} by the following ox-latex code:

3361             ;; Make sure cells are always centered while preserving
3362             ;; vertical separators.
3363             (let ((align (replace-regexp-in-string
3364                           "[lr]" "c" (org-latex--align-string table info))))

at

http://orgmode.org/w/org-mode.git?p=org-mode.git;a=blob;f=lisp/ox-latex.el;hb=9faf000e6a6977135a1d09dba4a078cdd9e04b38#l3361

I'm not certain whether I should be surprised that all non-centered alignments are changed to centered, or that in general any text with an 'l' or 'r' isn't valid in :align, or both.

This seems to have been commit 975260cb2596fb8cf0660cc91f2207c48b845699 to preserve column groups, but I'm not sure I understand the original problem or the fix.  What does replacing l's and r's with c's achieve?  Should I be defining new column types and/or just using a \newcommand that doesn't use the characters "l" or "r" instead of trying to directly set \columncolor directly in the alignment string?

Thanks...

Phil