From Newsgroup: comp.lang.tcl
Tcl 9.1a0 Release Announcement
==============================
July 30, 2025
The Tcl Core Team is pleased to announce the release of Tcl 9.1a0.
This is the first alpha release of Tcl 9.1.
Tcl is the Tool Command Language originated by John Ousterhout and his
team at U.C. Berkeley in the late 1980s. Its development is continued
by the efforts of a global network of volunteers guided by the Tcl Core Team.
We would like to express our gratitude to all those who submit bug
reports and patches. This information is invaluable in enabling us
to identify and eliminate problems. Such reports can be submitted here.
[Tcl Ticket Tracker](https://core.tcl-lang.org/tcl/ticket)
We ask that you log in (anonymous if you wish) to create tickets.
This deters abuse of the ticketing system:
[Tcl Contributor Login](https://core.tcl-lang.org/tcl/login)
Where to get the new releases
=============================
Tcl 9.1a0 sources are freely available as open source from the Tcl
SourceForge project's file distribution area:
[Tcl Source Distribution](https://sourceforge.net/projects/tcl/files/)
The Tcl 9.1a0 distribution is source code only. We keep links to some
third parties offering pre-built binaries for various systems here:
[Tcl Binary Distribution](https://www.tcl-lang.org/software/tcltk/bindist.html)
Tcl Summary
===========
The Tcl distribution delivers C source code that builds into a C library providing interpreters and related supports to execute programs written
in the Tcl programming language. Source code for the application program `tclsh` is also included. `tclsh` provides a shell for either interactive execution of Tcl commands, or execution of files containing Tcl programs.
Tcl is an extensible language, and the Tcl C library provides interfaces
for the creation of extension libraries adding new commands and features
to the core Tcl command set. Tcl 9 debuts the full feature set needed to package an application written in C and Tcl into a single file executable exploiting virtual filesystem archives.
Tcl 9.1 Release Summary
=======================
This is a new minor version of Tcl 9. When compared with the prior release
Tcl 9.0, there are new features and interfaces. Tcl 9.1 should remain compatible with scripts and packages written to the public interfaces of
Tcl 9.0. A summary of the most noteworthy changes is found below.
Tcl Improvement Proposals (TIPs)
================================
Each new user-visible feature in Tcl should find its origins in a Tcl Improvement Proposal (TIP). TIPs are published, edited, considered and
voted in public, and should contain valuable information about how a
feature came to be the way it is. See the full collection here:
[TIP Index](https://tip.tcl-lang.org/)
Tcl Changes Summary
===================
(from changes.md in the source code distribution)
The source code for Tcl is managed by fossil. Tcl developers coordinate all changes to the Tcl source code at
[Tcl Source Code](https://core.tcl-lang.org/tcl/timeline)
Release Tcl 9.1a0 arises from the check-in with tag `core-9-1-a0`.
Highlighted differences between Tcl 9.1 and Tcl 9.0 are summarized below,
with focus on changes important to programmers using the Tcl library and writing Tcl scripts.
# New commands and options
- [New options -backslashes, -commands and -variables for subst command](
https://core.tcl-lang.org/tips/doc/trunk/tip/712.md)
# New public C API
- [Tcl\_IsEmpty checks if the string representation of a value would be the empty string](
https://core.tcl-lang.org/tips/doc/trunk/tip/711.md)
- [Tcl\_GetEncodingNameForUser returns name of encoding from user settings](
https://core.tcl-lang.org/tips/doc/trunk/tip/716.md)
- [Tcl\_AttemptCreateHashEntry - version of Tcl\_CreateHashEntry that returns NULL instead of panic'ing on memory allocation errors](
https://core.tcl-lang.org/tips/doc/trunk/tip/717.md)
- [Tcl\_ListObjRange, Tcl\_ListObjRepeat, Tcl\_TclListObjReverse - C API for new list operations](
https://core.tcl-lang.org/tips/doc/trunk/tip/649.md)
# Performance
- [Memory efficient internal representations](
https://core.tcl-lang.org/tcl/wiki?name=New+abstract+list+representations)
for list operations on large lists.
# Bug fixes
- [tclEpollNotfy PlatformEventsControl panics if websocket disconnected](
https://core.tcl-lang.org/tcl/tktview/010d8f38)
For additional information:
===========================
Please visit the Tcl Developer Xchange web site:
[Tcl Developer Xchange](https://www.tcl-lang.org/)
This site contains a variety of information about Tcl/Tk in general, the
core Tcl and Tk distributions, Tcl development tools, and much more.
--
Tcl Core Team and Maintainers
Don Porter, Tcl Core Release Manager
--
| Don Porter Applied and Computational Mathematics Division |
|
donald.porter@nist.gov Information Technology Laboratory |
|
http://math.nist.gov/~DPorter/ NIST | |______________________________________________________________________|
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