how does R communicate with ESS?

[Tamas K Papp]

I just wanted to know how R comminucates with ESS when called from
Emacs on a Unix (specifically OS X) machine.  Is it just a redirection
of stdin and stdout, or is there more to it?  Could somebody please explain?

The reason I am asking is that I would like to ask the developers of
Rauqa to provide an interface to Emacs -- that way I could use
quartz() properly.  Now it just runs with R.app, which is a native OS
X application without a command line, but I don't think that adding
some kind of stdin/stdout capable interface would be a difficulty.

Thanks,

Tamas