ActiveTcl 8.6 from ActiveState

Try ActiveTcl 8.6

ActiveTcl is the industry-standard Tcl distribution, available for Windows, Linux and Mac OS X. Developers worldwide rely on ActiveTcl's completeness and ease-of-use, while corporate users protect their infrastructure and stay competitive with quality-assured ActiveTcl business solutions.

Organizations who rely on Solaris, AIX and HP-UX or older versions of Tcl across platforms trust our newest offering: ActiveTcl Business Edition.

About Tcl 8.6

Tcl 8.6 is a new version of the Tcl language currently in beta release that is compatible with the current 8.x line of releases. Many new features have been introduced, with numerous detailed changes. Also, the core set of extensions has been extended.

Which version should I choose?

Tcl 8.6 is currently in beta and not considered ready for stable deployments. Some 3rd-party modules and extensions that you may depend upon may not yet be compatible with Tcl 8.6. As a result you may want to continue to use Tcl 8.5 for the time being. However, you can safely install both ActiveTcl 8.5 and ActiveTcl 8.6 side-by-side on your computer so that you can experiment with Tcl 8.6 while still using Tcl 8.5 for your current code.

Download ActiveTcl 8.6 for your platform

Tcl 8.6 has many exciting new features. Download ActiveTcl 8.6 for your platform and try it out:

Looking for access to Solaris, AIX and HP-UX builds and repositories? Now available in ActiveTcl Business Edition

Release Highlights

Tcl Improvement Proposal #311 describes the expected release schedule and details the feature improvements that have gone into each pre-stable release of Tcl 8.6. Some highlights:

Core OO system

After years of choosing between many object oriented extensions to Tcl, one has finally been blessed and integrated into the core. It is designed with Tcl's natural flexibility in mind.


Tcl 8.6 has a new non-recursive bytecode engine (aka stackless). This allows several new features, notable coroutines (sometimes referred to as generators).

Core zlib support

Zlib compression is now included with Tcl, allowing for stream-based compression and other functionality.

PNG image format

Tk 8.6 adds support for the PNG image format (in addition to the existing GIF and PPM). This common format for icons and images makes creating great looking Tk applications even easier.

ttk::spinbox Widget

Tk 8.6 adds a themed version of the spinbox widget, consistent with the classic version but adapted to the widget theming engine.

Tcl DataBase Connectivity (TDBC)

Among the several new extensions that ship with the Tcl 8.6 core, TDBC stands out. It is an interface standard for databases to make connecting Tcl with databases more portable and secure.

Much more

There are many more changes in Tcl 8.6. Some resources for Tcl 8.6: