Chapter 58. Tcl/Tk 8.4

Tcl 8.4 provided significant performance improvements, many new commands and options, and three new Tk widgets.

Speed was a primary objective of Tcl/Tk 8.4. Version 8.0 provided major performance improvements to Tcl with the introduction of the bytecode compiler. But new features added in version 8.1 (in particular, multi-threaded support and internationalization support with Unicode strings) slowed down Tcl significantly. The goal for 8.4 was for scripts to run as fast as — or faster than — they did under 8.0, and the goal was achieved in almost all areas of the language.

Tcl/Tk 8.4 is perhaps the most significant release since 8.1 in terms of new features. Virtually all aspects of the language gained new functionality, and new widgets were added to the core for the first time since version 8.0.

Version 8.4 also marked the transition from Tcl being under the sole control of John Ousterhout to its management by the Tcl Core Team (TCT), which is composed of a group people who have been instrumental to Tcl's development over the years. The TCT is responsible for determining changes and new features for upcoming versions of Tcl. They also work with maintainers, who have responsibility over specific aspects of Tcl/Tk, and other community volunteers to actually implement the changes. Anyone can suggest a new feature or change to Tcl by submitting a Tcl Improvement Proposal (TIP). A description of the TIP process and a list of all submitted TIPs are available at http://www.purl.org/tcl/tip. Development of the 8.4 release was already in progress before the TIP process was in place, so not all new 8.4 features were controlled by TIPs; however, in this chapter, any new feature that was proposed by a TIP has that TIP number indicated.