Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Writing a Tcl Extension in Only Seven Years



Don E. Libes


Tcl is a command language library for embedding into other applications. It is often touted as the best language for this purpose and it is only natural that this claim should be investigated. This paper assists in that investigation by describing experiences over seven years with Expect. These experiences may help other extension language see some of the challenges that a single extension had to deal with while evolving at the same time as Tcl. Tcl and Expect users may also use these war stories to gain insight into why Expect works and looks the way it does today.

Proceedings Title
Proceedings of 5th Annual Tcl/Tk Worshop '97
Conference Dates
July 14-17, 1997
Conference Location
Boston, MA


Expect, Lessons learned, Software archaeology, Tcl


Libes, D. (1997), Writing a Tcl Extension in Only Seven Years, Proceedings of 5th Annual Tcl/Tk Worshop '97, Boston, MA, [online], (Accessed April 12, 2024)
Created July 1, 1997, Updated February 17, 2017