Tcl/Tk 9.0 Release Highlights and Incompatibilities

Tcl/Tk 9.0 has been released, bringing many new features but also some incompatibilities with the 8.x series.

Tcl is a script language created by John Ousterhout, widely used for rapid prototyping, scripting, GUI, and testing.

Key new features of Tcl 9.0 include:

64‑bit capacity for data values larger than 2 GB.

Full Unicode support with extended code‑point ranges and new encodings.

Zip file system that can mount zip archives as a file system.

Starkit‑style application deployment, allowing files to be bundled with executables.

A new notifier built on epoll/kqueue (fallback to select).

Numerous new commands and functionalities.

Important incompatibilities:

Namespace variable name resolution now defaults to the current namespace, not global.

I/O malencoding now raises an error by default.

Tilde (~) in path names no longer expands to the home directory.

The tcl_precision variable no longer affects numeric formatting.

Tk 9.0 also adds OS facility access, scalable vector graphics, full image metadata and alpha channel support, and enhanced platform gestures.

Download the source at https://www.tcl-lang.org/software/tcltk/download.html and see the full announcement at https://www.tcl-lang.org/software/tcltk/9.0.html?post=new .