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Tcl Source Code

Release Tcl 9.0b2 arises from the check-in with tag core-9-0-b2.

Highlighted differences between Tcl 9.0 and Tcl 8.6 are summarized below, with focus on changes important to programmers using the Tcl library and writing Tcl scripts.

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: > 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()

New commands

• array default, array for
• coroinject, coroprobe
• clock add weekdays
• const, info const*
• dict getdefault
• file tempdir, file home, file tildeexpand
• info commandtype
• 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
• Functions: isinf() isnan() isnormal() issubnormal() isunordered()
• fpclassify
• Function int() no longer truncates to word size

tcl::oo facilities

• private variable and methods
• method -export, method -unexport