Peter Daalgard
The R-Tcl/Tk interface -- Status and Perspectives
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Since version 1.1, R has had the tcltk package which enables the
creation of simple graphical user interfaces. In the talk, I will
discuss new developments and future plans.

The main news relate to the use of Tcl objects in the C interface.
To a large extent, this bypasses the conversion of objects to and from
string form, with the associated "quoting hell". As of this writing,
you still need to build up a Tcl command as a character string, but I
hope to replace this by a Tcl object based mechanism in the near
future.

Work continues on the language interfacing front. Some problems have
been solved, but new ones pop up as one tries to interface to more
extensions and widgets. For instance, using the TkTable widget
requires a better interface to Tcl's associative arrays and/or a
method for allowing callbacks to return a value. Recent discussions on
the implementation of a full GUI for R suggest that it might well be
worth it also to develop the reverse interface (R as a Tcl extension).

One of the most attractive prospects of using Tcl/Tk is the
possibility of using 3rd party extensions. The TkTable widget could be
used to build an improved data editor, and possibly also for
integrated text and graphics display (the TkHtml widget is another
contender for this role). For advanced dynamic graphics applications,
the Tk canvas has limitations but the Zinc extension looks very
promising and if you want to go really wild, have a look at the
visualization toolkit, Vtk.