[ESS] Font locking in *R* {was "ESS usage poll"}

[Martin Maechler]

>>>>> "EH" == Emanuel Heitlinger <emanuelheitlinger at googlemail.com>
>>>>>     on Thu, 10 Jun 2010 18:06:58 +0200 writes:

[........]

    EH> At Thu, 10 Jun 2010 22:36:17 +1200, Patrick Connolly wrote:

    >> > 4. If you could only request one feature, what would it be?
    >> 
    >> A clever way of dealing with the unbalanced quotes (to
    >> R's way of thinking) that can be returned to Emacs from a
    >> bash call.  The ` character screws up the font colouring.
    >> Can't imagine how it could be done, and I realize it's
    >> really a bash issue, but I'd be very grateful if someone
    >> could work out a way of dealing with it.  I invariably
    >> see colours as though it's all a string irrespective of
    >> function names or anything else.  I tire of deleting the
    >> offending character before I can read R code properly.
    >> I'm very lazy, I know.
    >> 
    >> HTH

    EH> I second that: This font coloring screw up is the only issue I am
    EH> having at the moment. I was never able to investigate it
    EH> further, as Patrick did.

As Deepayan Sarkar said  in his reply, the problem here is a
bigger issue, namely that we have font locking (aka "font coloring")
in the *R* (and *.Rout) buffers, the same as in the *.R ones.

Font locking of `...` as a string is clearly necessary, because
of what it means in R; please learn about it if you need.

However, I agree that it's painful if some R packages
("mgcv", "lasso2", notably) produce noise on loading and that
noise uses old-style  `quoted text'  (backward-quote text forward-quote),
because there you have an opening backquote but no closing one.

BTW, the current workaround is very fast, once you're used to
it: 
 " C-r ` C-d "  (search backwards for backquote, and delete it)
   ---------
{{I can still sympathize with Patrick who's tired of doing that :-)}}


The question is really what we should do.

I do like the font locking of *input* typed in *R* buffers,
including the coloring reminding me that I need a closing quote.
What Deepayan (and I) really would like is to have the 
input font-locked but all the "console" output remain untouched
(maybe even getting a slightly dimmed color scheme).

Martin Maechler, ETH Zurich