An X11 Toolkit Based on the Tcl Language

This paper describes a new toolkit for X11 called Tk. The overall functions provided by Tk are similar to those of the standard toolkit Xt. However, Tk is implemented using Tcl, a lightweight interpretive command language. This means that Tk’s functions are available not just from C code compiled into the application but also via Tcl commands issued dynamically while the application runs. Tcl commands are used for binding keystrokes and other events to application-specific actions, for creating and configuring widgets, and for dealing with geometry managers and the selection. The use of an interpretive language means that any aspect of the user interface may be changed dynamically while an application executes. It also means that many interesting applications can be created without writing any new C code, simply by writing Tcl scripts for existing applications. Furthermore, Tk provides a special send command that allows any Tk-based application to invoke Tcl commands in any other Tk-based application. Send allows applications to communicate in more powerful ways than a selection mechanism and makes it possible to replace monolithic applications with collections of reusable tools. This paper will appear in the Proceedings of the 1991 Winter USENIX Conference. An X11 Toolkit Based on the Tcl Language December 4, 1990