Tcl Source Code

Tcl 9:

  * 64-bit capacity: Data values larger than 2Gb

  * 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.

  * Unix notifiers available using epoll() or kqueue()
    - relieves limits on file descriptors imposed by legacy select()

  * Notable incompatibilities
    - Unqualified varnames resolved in current namespace, not global.
    - 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
    - Removed the "identity" encoding
    - $::tcl_precision no longer controls string generation of doubles
    - Removed Tcl 7 legacies: [case], [puts] [read] variant syntaxes
    - Removed subcommands [trace variable|vdelete|vinfo]
    - No -eofchar option for channels anymore for writing.
    - On Windows 10+ (Version 1903 or higher), system encoding is always utf-8.

  * Incompatibilities in C public interface
    - Many arguments expanded type from int to Tcl_Size
    - 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
    - Removed routines:

    - [ledit]
    - [lpop]
    - [lremove]
    - [lseq]
    - [package files]
    - [string insert], [string is dict]
    - [tcl::process]
    - [*::build-info]

  * New command options
    - [regsub ... -command ...]
    - [lsearch ... -stride ...]
    - [clock scan ... -validate ...]
    - [socket ... -nodelay ... -keepalive ...]
    - [vwait] controlled by several new options

  * 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

    - [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 ...]
    - 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