[ESS] Interact with ESS from R

[Gábor Csárdi]

Dear All,

I am trying to make crayon (http://www.r-pkg.org/pkg/crayon) work with
Emacs more smoothly. crayon can add ANSI color to strings printed to
the terminal.

As I understand from http://www.emacswiki.org/emacs/AnsiColor recent
versions of Emacs support this out of the box, as long as
(add-hook 'shell-mode-hook 'ansi-color-for-comint-mode-on)
(add-to-list 'comint-output-filter-functions 'ansi-color-process-output)
was done.

I can check the version of Emacs from the INSIDE_EMACS environment
variable, so I can easily tell if it is recent enough to have
ansi-color.el. So far so good.

Is there a way to check if 'ansi-color-for-comint-mode-on was run and
if 'comint-output-filter-functions contains
'ansi-color-process-output?

In general, can I call Emacs lisp functions from the embedded R process?

I am sorry if this is documented somewhere, I tried to find it in the
docs, without luck.

Thanks, Best,
Gabor