Tcl/Tk 9.0

Latest Release: Tcl/Tk 9.0.0 (Sep 26, 2024)

Tcl/Tk 9.0 is the latest major release of both Tcl and Tk. It features many new capabilities, and presents some incompatibilities with Tcl/Tk 8.

Download Tcl/Tk 9.0.0 Source Releases

Highlights of Tcl 9.0

64-bit Capacity: Data values larger than 2Gb
Unicode and Encodings: full codepoint range, added encodings, encoding profiles to govern I/O, and more.
Zip Filesystems: mount zipfiles as filesystems
Attached Archives: enable starkit-style deployment of apps, with support data in filesystem archives attached to executable or libraries. Build tclsh and wish this way.
New Notifiers: The central event handling engine in Tcl is now constructed on top of the system calls epoll or kqueue when they are available. The select based implementation also remains for platforms where they are not.
Many new commands and features

See below for a more complete summary of changes in Tcl.

Important Incompatibilities in Tcl 9.0

Namespace varname resolution: Current namespace, not global.
I/O malencoding: now raises error by default.
Tilde (~) in pathnames: no longer interpreted as home directory.
tcl_precision no longer has effect on number formatting

Highlights of Tk 9.0

Access to OS facilities: notifications , print , and tray systems
Scalable Vector Graphics: partial support in images, extensive use to enable scalable widget and theme appearances.
Images: full access to metadata and alpha channel.
Platform Features and Conventions: many improvements, including two-finger gesture support where available.

See below for a more complete summary of changes in Tk.

Porting code to Tcl 9

Many Tcl programs written for Tcl 8 will run unchanged in Tcl 9. Many more Tcl programs can be modified in small and simple ways to produce a new program that runs in both Tcl 8 and Tcl 9. Extensions and applications using the public Tcl C APIs will involve more effort, but it is still within reasonable reach to produce source code supporting both Tcl 8 and Tcl 9 while both releases remain in widespread use.

Tk 9.0.0 does not support Tcl 8.6. Tk 9.0.0 extends Tcl 9.0.0. To make use of Tk 9.0.0, first the new Tcl release, Tcl 9.0.0, needs to be present. As new Tk features are developed, expect them to appear in Tk 9, but not necessarily in Tk 8.6.

See the following links for an accumulation of migration advice:

There has been much progress already porting many known applications, extensions, and packages in the Tcl world to compatibility with Tcl/Tk 9:

Summary of changes for Tcl

Major Features

64-bit capacity: Data values larger than 2 GB

Strings can be any length (that fits in your available memory)
Lists and dictionaries can have very large numbers of elements

Internationalization of text

Full Unicode range of codepoints
New encodings: utf-16/utf-32/ucs-2(le|be), CESU-8, etc.
encoding options -profile, -failindex manage encoding of I/O
msgcat supports custom locale search list
source defaults to -encoding utf-8

Zip filesystems and attached archives

Packaging of the Tcl script library with the Tcl binary library, meaning that the TCL_LIBRARY environment variable is usually not required
Packaging of an application into a virtual filesystem is now a supported core Tcl feature

Unix notifiers available using epoll() or kqueue()

This relieves limits on file descriptors imposed by legacy select() and fixes a performance bottleneck

Notable incompatibilities

Unqualified varnames resolved in current namespace, not global. Note that in almost all cases where this causes a change, the change is actually the removal of a latent bug
No --disable-threads build option. Always thread-enabled
I/O malencoding default response: raise error (-profile strict)
Windows platform needs Windows 7 or Windows Server 2008 R2 or later
Ended interpretation of ~ as home directory in pathnames (see file home and file tildeexpand for replacements when you need them)
Removed the identity encoding (there were only ever very few valid use cases for this; almost all uses were systematically wrong)
Removed the encoding alias binary to iso8859-1
$::tcl_precision no longer controls string generation of doubles (if you need a particular precision, use format)
Removed pre-Tcl 8 legacies: case, puts and read variant syntaxes
Removed subcommands trace variable|vdelete|vinfo
Removed -eofchar option for write channels
On Windows 10+ (Version 1903 or higher), system encoding is always utf-8
%b/%d/%o/%x format modifiers (without size modifier) for format and scan always truncate to 32-bits on all platforms
%L size modifier for scan no longer truncates to 64-bit
Removed command ::tcl::unsupported::inject (see coroinject and coroprobe for supported commands with significantly more comprehensible semantics)

Incompatibilities in C public interface

Extensions built against Tcl 8.6 and before will not work with Tcl 9.0; ABI compatibility was a non-goal for 9.0. In most cases, rebuilding against Tcl 9.0 should work except when a removed API function is used
Many arguments expanded type from int to Tcl_Size, a signed integer type large enough to support 64-bit sized memory objects. The constant TCL_AUTO_LENGTH is a value of that type that indicates that the length should be obtained using an appropriate function (typically strlen() for char * values)
Ended support for Tcl_ChannelTypeVersion less than 5
Introduced versioning of the Tcl_ObjType struct
Removed macros CONST*: Tcl 9 support means dropping Tcl 8.3 support. (Replaced with standard C const keyword going forward)
Removed registration of several Tcl_ObjTypes
Removed API functions:
- Tcl_Backslash()
- Tcl_*VA()
- Tcl_*MathFunc*()
- Tcl_MakeSafe()
- Tcl_(Save|Restore|Discard|Free)Result()
- Tcl_EvalTokens()
- Tcl_(Get|Set)DefaultEncodingDir()
- Tcl_UniCharN(case)cmp()
- Tcl_UniCharCaseMatch()
Revised many internals; beware reliance on undocumented behaviors

New commands

array default — Specify default values for arrays (note that this alters the behaviour of append, incr, lappend)
array for — Cheap iteration over an array’s contents
chan isbinary — Test if a channel is configured to work with binary data
coroinject, coroprobe — Interact with paused coroutines
clock add weekdays — Clock arithmetic with week days
const, info const* — Commands for defining constants (variables that can’t be modified)
dict getwithdefault — Define a fallback value to use when dict get would otherwise fail
file home — Get the user home directory
file tempdir — Create a temporary directory
file tildeexpand — Expand a file path containing a ~
info commandtype — Introspection for the kinds of commands
ledit — Equivalent to lreplace but on a list in a variable
lpop — Remove an item from a list in a variable
lremove — Remove a sublist from a list in a variable
lseq — Generate a list of numbers in a sequence
package files — Describe the contents of a package
string insert — Insert a string as a substring of another string
string is dict — Test whether a string is a dictionary
tcl::process — Commands for working with subprocesses
*::build-info — Obtain information about the build of Tcl
readFile, writeFile, foreachLine — Simple procedures for basic working with files
tcl::idna::* — Commands for working with encoded DNS names

New command options

chan configure ... -inputmode ... — Support for raw terminal input and reading passwords
clock scan ... -validate ...
info loaded ... ?prefix?
lsearch ... -stride ... — Search a list by groups of items
regsub ... -command ... — Generate the replacement for a regular expression by calling a command
socket ... -nodelay ... -keepalive ...
vwait controlled by several new options
expr string comparators lt, gt, le, ge
expr supports comments inside expressions

Numbers

0NNN format is no longer octal interpretation. Use 0oNNN
0dNNNN format to compel decimal interpretation
NN_NNN_NNN, underscores in numbers for optional readability
Functions: isinf(), isnan(), isnormal(), issubnormal(), isunordered()
Command: fpclassify
Function int() no longer truncates to word size

TclOO facilities

private variables and methods
class variables and methods
abstract and singleton classes
configurable properties
method -export, method -unexport

Summary of changes for Tk

Many improvements to use of platform features and conventions

Built-in widgets and themes are scaling-aware
Improved support of two-finger gestures, where available
The tk windowingsystem “aqua” needs macOS 10.10 or later

New commands and options

tk sysnotify — Access to the OS notifications system
tk systray — Access to the OS tray facility
tk print — Access to the OS printing facility

Widget options

New ttk::progressbar option: -text
$frame ... -backgroundimage $img -tile $bool
$menu id, $menu add|insert ... ?$id? ...
$image get ... -withalpha ...
New ttk::combobox and ttk::entry options: -placeholder and -placeholderforeground
All indices now accept the forms end, end-int, int+|-int

Improved widget appearance

ttk::notebook with nondefault tab positions

Images

Partial SVG support
Read/write access to photo image metadata