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 ....
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.
libtclreadline1.2.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 addstring
adds a string to the completer. If the string contains white spaces, each
of the words will be completed consecutively when hitting <Tab>. Example:
typing but<Tab> will complete to button. Hitting <Tab> again will complete
to "button pathName". ...
::tclreadline::readline completestring
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 initializehistoryfile
initialize the tclreadline interface and read the history from
the historyfile. On succes an empty string is returned. This command has
to be called before any other tclreadline commands.
::tclreadline::readline
readprompt
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 writehistoryfile
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.
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::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:
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 defines the following variables in the namespace
::tclreadline: (for backwards compatiblity the global variables tclreadline_version,
tclreadline_patchLevel and tclreadline_library are still present).
tclreadline::version (read-only)
holds the version string "1.2".
tclreadline::patchLevel
(read-only)
holds the patch level string "1.2.0".
tclreadline::library (read-only)
holds the library string "/usr/lib/tclreadline1.2".
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.
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.
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>