bionic (3) tclreadline.3tcl.gz
NAME
tclreadline - gnu readline for the tcl scripting language
SYNOPSIS
::tclreadline::readline command [options]
DESCRIPTION
The tclreadline package makes the gnu readline available to the scripting language tcl. The primary
purpose of the package is to facilitate the interactive script development by the means of word and file
name completion as well as history expansion (well known from shells like bash).
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 processed as well as events from the
tclreadline line interface.
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
....
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 to 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.
libtclreadline2.1.0.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 but<Tab> will complete to button. Hitting <Tab> again will complete to "button pathName".
...
::tclreadline::readline complete string
returns 1 if string is a complete tcl command and 0 otherwise.
::tclreadline::readline customcompleter [string]
Register the proc string as 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 of 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).
::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 the 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 rises
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]
w/o 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 w/o argument might not work if tclreadline was compiled with an older version of
libreadline.
::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 "2.1.0".
tclreadline::patchLevel (read-only)
holds the patch level string "2.1.0".
tclreadline::library (read-only)
holds the library directory string.
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
the .tclshrc file in the HOME directory, which 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
if {$tcl_interactive} {
package require tclreadline
::tclreadline::Loop
}
which will enter the tclreadline main loop.
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.
the .inputrc file in the users 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.
SEE ALSO
The official tclreadline web site at:
http://www.zellner.org/tclreadline/
AUTHOR
Johannes Zellner, <johannes@zellner.org>
CONTRIBUTIONS, SUGGESTIONS AND PATCHES
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> <david@debian.org>, Matthew Clarke <Matthew_Clarke@mindlink.bc.ca>
DEBIAN PACKAGE
David Engel <dlengel@home.com>, <david@debian.org>
DISCLAIMER
tclreadline comes with a BSD type license. The read-only variable tclreadline::license holds the
complete license statement.