[R-gui] GUI toolkit comparison

Hi Duncan,

For me, the motivation with RGtk is that Gtk is an important
toolkit used in many applications that I think we want to be able
integrate R with.

I think Gtk is a great GUI toolkit for Linux/Unix, but most
of my end-users who really need a GUI (rather than a CLI)
are Windows or Mac users, and as you probably know, trying
to compile Gtk on those systems is not easy, (although I do
enjoy running GIMP on Windows which uses Gtk!).

RDCOM seems like a nice idea, but I have chosen Tcl/Tk for
my R-GUI projects so far because it seems to rely on less
Microsoft proprietary technology (potentially complicating
GPL/BSD licenses), and because Tcl/Tk seems to be more
platform independent between Windows and Mac.  (Correct me
if I am wrong here.)

Often we may be asked to give a microarray workshop at short
notice (using R packages from Bioconductor).  If there are
likely to be people in the workshop who are unfamiliar with
command-line interfaces, we will use GUI versions of some of
our Bioconductor packages.  Often we don't get much warning
of whether participants will be using Windows or Mac or
Linux (rare) or a mixture.  It would be a lot more work for us
to simultaneously test a Gtk-version of our GUI and an R-DCOM
version leading up to a workshop like this.

If I've sounded vague about whether R-DCOM works on Mac, that's
because I really don't know.  Obviously Microsoft software is
generally more easily available on Mac than on Linux, but does
that include DCOM?

Regards,
James