[ESS-bugs] Alt+; pressed twice does not uncomment the block in SAS mode

[Richard M. Heiberger]

I will confirm the problem.  I have an analysis at the end of this message.

In myfile.s, highlight several lines, then press M-; .
The entire region is now commented with a leading ##.
Then re-highlight the same lines, and press M-; , now the commented
region has its ## removed.

In myfile.sas, highlight several lines, then press M-; .
The lines are now prefixed with
\*\|/\*
and postfixed with
;\|\*/

This looks like an attempt to prefix with /* and postfix with */ but
the escaping of special characters got scrambled.


Now rehighlight the same region and again press M-; .
We expect, based on the behavior in myfile.s, that the comment
information would be removed.  It isn't removed.  Instead, another
set is placed on each of the lines in the region.

Now I see it.  SAS has two types of comments structures,
the  * xxxx ;
and /* xxxx */

comment-dwim function (called by M-;) is doing something with the
regular expression defining those comments and coming up with a scramble
mixture of both commenting methods.