tclreadline(n)

📦

version 2.4.1 · 5 versions

🎀 NAME 🎀

okay so bestie, this is the tclreadline(n) manual, and the whole personality is right here: tclreadline is gnu readline for the tcl scripting language. That's the name-line tea, folded in near the top. 💖

✨ SYNOPSIS ✨

::tclreadline::readline command [options]

That's the shape of every call, bestie.

💅 DESCRIPTION 💅

The tclreadline package makes GNU readline available to the scripting language Tcl. Its primary purpose is to facilitate interactive script development by the means of word and file name completion as well as history expansion (well known from shells like bash). It's giving "shell energy, but make it Tcl."

Additionally, tclreadline can also be used for Tcl scripts which want to use a shell like input interface. In this case the ::tclreadline::readline read command has to be called explicitly.

The advantage of tclreadline is that it uses the callback handler mechanism of the GNU readline while it processes Tcl events. This way X events from a wish GUI will be processed as well as events from the tclreadline line interface. main character energy: both event streams get processed, no cap.

tclreadline is basically a shared library and a few Tcl scripts which are accessed with the Tcl package require command. Therefore tclreadline should work with all common extensions like blt, itcl, itk, tix .... iconic compatibility era.

🫶 COMMANDS 🫶

If you want to use tclreadline as a line interface for developing Tcl scripts, you probably don't have to read this section. In this case the only thing you should do is modify your .tclshrc according to the section FILES.

For the functionality of the GNU readline you should refer to the readline's documentation.

The following list will give all commands, which are currently implemented in the shared lib (e.g. libtclreadline2.4.1.so). Additional commands were introduced in a startup script tclreadlineSetup.tcl, which lives in the tclreadline installation directory. (typically something like /usr/local/lib/tclreadline ..) These commands are primarily for internal use and not documented here.

Note that all commands reside in the namespace ::tclreadline::.

::tclreadline::readline add string — adds a string to the completer. If the string contains white spaces, each of the words will be completed consecutively when hitting Tab. Example:

::tclreadline::readline add "button pathName ?options?"

Typing butTab will complete to button. Hitting Tab again will complete to "button pathName". ... yes, the dots are part of the vibe.

::tclreadline::readline complete string — returns 1 if string is a complete tcl command and 0 otherwise. vibe check: complete vs not complete.
::tclreadline::readline customcompleter [string] — registers the proc string as the custom completer. This proc is called with exactly four arguments each time completion takes place: the word to complete ("text"), the "start" and "end" positions of this word in the line entered so far, and this line ("line"). The custom completion script should return an array of strings which is a list of completions for "text". If there are no completions, it should return an empty string "". The first entry in the returned list is the substitution for "text". The remaining entries are the possible completions. If the custom completion script returns an empty string and builtin completion is enabled (see tclreadline::readline builtincompleter), the builtin completer is called. tclreadline::readline customcompleter simply returns the current custom completer if called w/o string. To turn off custom completion, call tclreadline::readline customcompleter with an empty string.

Example: % puts $b<TAB> will call the custom completer with the four arguments "$b", "5", "8" and "puts $b". The custom completer could return a string like "$bl $black $blue", which will complete "$b" to "$bl" (the longest match) and offer a list of two further matches "$black" and "$blue".

For further reference, see the proc tclreadline::ScriptCompleter in the file tclreadlineSetup.tcl.

::tclreadline::readline builtincompleter [bool] — enable or disable the builtin completer. If the builtin completer is enabled, it will be invoked either if there is no custom completer, or the custom completer returned an empty string. The builtin completer is on by default. tclreadline::readline builtincompleter returns the current custom completer (also, if called w/o the bool argument). the wording is a whole mood, but that's what it says.
::tclreadline::readline eofchar [script] — set a script which will be called, if readline returns the eof character (this is typically the case if Ctrl+D is entered at the very beginning of the line). The default for this script is "puts {}; exit". Setting this to an empty value disables any action on eof. tclreadline::readline eof returns the current eof script.
::tclreadline::readline initialize historyfile — initialize the tclreadline interface and read the history from historyfile. On success an empty string is returned. This command has to be called before any other tclreadline commands.
::tclreadline::readline read prompt — prints the prompt to stdout and enters the tclreadline event loop. Both readline and X events are processed. Returns the (eventually history-expanded) input string. tclreadline::readline read raises an error if an error occurs while evaluating a script completer.
::tclreadline::readline write historyfile — writes the history to the historyfile. This command is called automatically from the internal routine ::tclreadline::Exit. If the variable tclreadline::historyLength is non-negative, the historyfile will be truncated to hold only this number lines.
::tclreadline::readline reset-terminal [terminalName] — without argument: reset the state of the terminal to what it was before tclreadline was used. With argument: reinitialize readline's idea of the terminal settings using terminalName as the terminal type. The form without argument might not work if tclreadline was compiled with an older version of libreadline.
::tclreadline::readline historyexpansion [bool] — enable or disable history expansion. With no argument, returns the current value.
::tclreadline::readline bell — ring the terminal bell, obeying the setting of bell-style -- audible or visible.
::tclreadline::text — return the current input.
::tclreadline::readline update — redraw the current input line.
::tclreadline::Print [yes / no] — turns on or off the default behavior of tclsh to print the result of every command. This is turned on by default, so it will just behave as the tclsh w/o tclreadline. Turning off might be useful, when reading binary data for example. If ::tclreadline::Print is called w/o arguments, it returns the current setting.
::tclreadline::Loop [historyfile] — enter the tclreadline main loop. This command is typically called from the startup resource file (something .tclshrc, depending on the interpreter you use, see the file sample.tclshrc). The main loop sets up some completion characteristics as variable -- try something like "puts $b<TAB>" -- and command completion -- try "puts [in<TAB>". If the optional argument historyfile is given, this file will be used for reading and writing the command history instead of the default .tclsh-history. ::tclreadline::Loop will normally not return. If you want to write your own main loop and/or own custom completers, it is probably a good idea to start with tclreadline::Loop (see the file tclreadlineSetup.tcl).
::tclreadline::prompt1 — a proc which is called by ::tclreadline::Loop and returns a string which will be displayed as the primary prompt. This prompt will be something like "[info nameofexecutable] \[[pwd]\]" possibly fancy colored. The default proc is defined on entering the ::tclreadline::Loop, if it is not already defined. So: If you define your own proc ::tclreadline::prompt1 before entering ::tclreadline::Loop, this proc is called each time the prompt is to be displayed. Example:

package require tclreadline
namespace eval tclreadline {
    proc prompt1 {} {
        return "[clock format [clock seconds]]> "
    }
}
::tclreadline::Loop

Note that non-printable control characters as color control characters must be enclosed in literal ctrl-a / ctrl-b to tell readline the length of the printable prompt. See for example the variable prompt_string in the file tclreadlineSetup.tcl in your tclreadline installation directory.

::tclreadline::prompt2 — a proc which is called by ::tclreadline::Loop and returns a string which will be displayed as the secondary prompt when interactively prompting for continuation of an incomplete command.

🦋 VARIABLES 🦋

tclreadline defines the following variables in the namespace ::tclreadline:: (for backwards compatibility the global variables tclreadline_version, tclreadline_patchLevel and tclreadline_library are still present).

tclreadline::version (read-only) — holds the version string "2.4.1".
tclreadline::patchLevel (read-only) — holds the patch level string "2.4.1".
tclreadline::library (read-only) — holds the library string "/usr/lib64/tcl8.6/tclreadline2.4.1".
tclreadline::license (read-only) — holds a BSD license statement.
tclreadline::historyLength — number of lines, which will be written to the historyfile. This number is -1 by default, which means that the historyfile will not be truncated. See also tclreadline::write.

🎀 FILES 🎀

Okay bestie, here's the file lore 💖

The .tclshrc file in the HOME directory — this one is read on tclsh startup. Alternatively, the name of this initialization file might be .wishrc ... depending on what interpreter you use. These files should typically contain something like this:

                  if {$tcl_interactive} {
                      package require tclreadline
                      ::tclreadline::Loop
                  }

...which will enter the tclreadline main loop. Slay.

The .tclsh-history file in the HOME directory. On startup, commands will be read from this file. On exit, the readline history is written to this file. Note that if you abort tclsh with <cntrl-c>, no history is written. For the future it is planned to set up a signal handler, which will write the history on <ctrl-c> before exiting. Important little caveat, no cap 🫶
The .inputrc file in the user's HOME directory. This file is used normally for all programs which use the gnu readline (e.g. bash). The global readline settings there will be valid also for tclreadline. Additionally the .inputrc might hold conditional settings for the implementation name tclreadline. Example of some lines in your .inputrc:

                  $if tclreadline
                  "\C-xp": "puts $env(PATH)"
                  $endif

For further documentation please refer to the gnu readline documentation. 💅

💀 BUGS 💀

Citing the readline manual: “It's too big and too slow.” That's the whole bug note, bestie 😭💀

👀 SEE ALSO 👀

The official tclreadline web site at:

https://github.com/flightaware/tclreadline/

Go look, it's giving iconic 🔥

✨ AUTHOR ✨

Johannes Zellner, <johannes@zellner.org> — author behavior, honestly 👑

🫶 CONTRIBUTIONS, SUGGESTIONS AND PATCHES 🫶

These legends contributed, suggested, and patched:

Magnus Eriksson <magnus.eriksson@netinsight.se>
Les Johnson <les@infolabs.com>
Harald Kirsch <kir@iitb.fhg.de>
Christian Krone <krischan@sql.de>
Larry W. Virden <lvirden@cas.org>
David Engel <dlengel@home.com> and <david@debian.org>
Matthew Clarke <Matthew_Clarke@mindlink.bc.ca>

Group project energy, and they ate 🫶✨

🍓 DEBIAN PACKAGE 🍓

David Engel <dlengel@home.com>, <david@debian.org> — Debian package person, keeping it cute and packaged 🎀

🌈 DISCLAIMER 🌈

tclreadline comes with a BSD type license. The read-only variable tclreadline::license holds the complete license statement. Read it, bestie — legal lore matters 💜

That's the whole page, bestie 💖 — page tclreadline(n), version 2.4.1, by Johannes Zellner. The footer's date slot is empty on this copy, so no invented date era, periodt. 🌈✨

📦 where this page comes from

epel 10: tcl-tclreadline 2.4.1-1.el10_1 · BSD-3-Clause
epel 9: tcl-tclreadline 2.4.1-1.el9 · BSD-3-Clause
💖 girlified by deepseek-ai/DeepSeek-V4.1-Flash-1017 on 2026-11-06: a language model's rewrite of the original, under its terms