Version 8.0 of the Tcl tool command language, a freely-distributable, simple, interpreted language designed for use as a common extension and customization language for applications, is now available for use on RCS. Tk, the X windowing companion product to Tcl, is also available.
Designed and implemented by Dr. John Ousterhout at the University of California at Berkeley in the hope that application designers could spend more of their time on applications and less on scripting languages, and in the hope that users could spend less time learning new scripting languages for each new application, Tcl is clean and regular, and relatively easy for new users to learn. Many useful applications, some of them sold commercially, use Tcl as their scripting language.
Command-oriented, Tcl places any commands added by applications and users on an equal footing with the built-in Tcl commands. In addition, simple customization scripts (such as preference initialization scripts) usually look much like novice users expect them to, consisting of a series of simple commands which set options.
Tcl is implemented as a C library, which can be embedded in an application. In turn, the application can add its own commands to the interpreter (using a clean C interface).
The Tk toolkit, an extension of Tcl containing a group of new Tcl commands, provides a Tcl interface to the X Window System, as well as one of the easiest ways to build a graphical interface to an application. And due to the interpreted nature of Tcl, Tk-based interfaces tend to be much more customizable and dynamic than those built with one of the C-based or C++-based toolkits. Tk implements the Motif "look and feel," and also provides a mechanism by which one application can send Tcl scripts to other Tk-based applications running on the same display, for easy cooperation between tools.
Tcl/Tk 8.0 is a significant release and has many new features, some of which include:
Users most commonly use Tcl/Tk by writing Tcl scripts and then running them via the Tcl interpreter, tclsh. However, you may also run Tcl as an interactive shell by entering the following command at a UNIX prompt:
tclsh8.0
It is also more common to use the Tcl X Windows toolkit, Tk, by running scripts, but you can run this extension in interactive mode by running wish8.0 (the Tk interpreter) by typing the following command at a UNIX prompt:
wish8.0
Those users familiar with using Tcl/Tk may realize that aliases to the tclsh8.0 and wish8.0 commands typically exist, which allow you to start the tcl shell with the simpler command tclsh, or wish8.0 with just wish. In the RCS environment, however, tclsh and wish are aliases to the previous version of Tcl/Tk, so users must enter the full tclsh8.0 and wish8.0 commands in order to make sure they access Version 8 of these programs.
For more information on Tcl/Tk, please refer to the URL http://sunscript.sun.com/TclTkCore/8.0.html.