Tcl is an interpreted "tool command language" designed by John Ousterhout while at UC Berkeley. Tk is an associated X window toolkit. Both have been integrated into Ptolemy. Parts of the graphical user interface and all of the textual interpreter ptcl are designed using them. Several of the stars in the standard star library also use Tcl/Tk. This chapter explains how to use the most basic of these stars, TclScript, as well how to design such stars from scratch. It is possible to define very sophisticated, totally customized user interfaces using this mechanism.In this chapter, we assume the reader is familiar with the Tcl language. Documentation is provided along with the Ptolemy distribution in the
$PTOLEMY/tcltk/itcl/man directory in Unix man page format. HTML format documentation is available from the other.src tar file in $PTOLEMY/src/tcltk. Up-to-date documentation and software releases are available by on the SunScript web page at http://www.sunscript.com. There is also a newsgroup called comp.lang.tcl. This news group accumulates a list of frequently asked questions about Tcl which is available http://www.teraform.com/%7Elvirden/tcl-faq/.The principal use of Tcl/Tk in Ptolemy is to customize the user interface. Stars can be created that interact with the user in specialized ways, by creating customized displays or by soliciting graphical inputs.