NAME¶
Term::Clui.pm - Perl module offering a Command-Line User Interface
SYNOPSIS¶
use Term::Clui;
$chosen = choose("A Title", @a_list); # single choice
@chosen = choose("A Title", @a_list); # multiple choice
# multi-line question-texts are possible...
$x = choose("Which ?\n(Mouse, or Arrow-keys and Return)", @w);
$x = choose("Which ?\n".help_text(), @w);
if (confirm($text)) { do_something(); };
$answer = ask($question);
$answer = ask($question,$suggestion);
$password = ask_password("Enter password:");
$filename = ask_filename("Which file ?"); # with Tab-completion
$newtext = edit($title, $oldtext);
edit($filename);
view($title, $text) # if $title is not a filename
view($textfile) # if $textfile _is_ a filename
edit(choose("Edit which file ?", grep(-T, readdir D)));
DESCRIPTION¶
Term::Clui offers a high-level user interface to give the user of command-line
applications a consistent "look and feel". Its metaphor for the
computer is as a human-like conversation-partner, and as each
question/response is completed it is summarised onto one line, and remains on
screen, so that the history of the session gradually accumulates on the screen
and is available for review, or for cut/paste. This user interface can
therefore be intermixed with standard applications which write to STDOUT or
STDERR, such as
make,
pgp,
rcs etc.
For the user,
choose() uses either (since 1.50) the mouse;
or arrow keys (or hjkl) and Return; also
q to quit, and SpaceBar or
Button3 to highlight multiple choices.
confirm() expects
y, Y, n or N. In general, ctrl-L redraws the (currently active bit of the)
screen.
edit() and
view() use the
default EDITOR and PAGER if possible.
It's fast, simple, and has few external dependencies. It doesn't use
curses (which is a whole-of-screen interface); it uses a small subset
of vt100 sequences (up down left right normal and reverse) which are very
portable, and also (since 1.50) the
SET_ANY_EVENT_MOUSE and
kmous (terminfo) sequences, which are supported by all
xterm,
rxvt,
konsole,
screen,
linux,
gnome and
putty terminals.
There is an associated file selector, Term::Clui::FileSelect
Since version 1.60, a speaking interface is provided for the visually-impaired
user; it employs
eflite or
espeak. Speech is turned on if the
CLUI_SPEAK environment variable is set to any non-empty string. Since
version 1.62, if
speakup is running, it is silenced while Term::Clui
runs, and then restored. Because Term::Clui's metaphor for the computer is a
human-like conversation-partner, this works very naturally. The application
needs no modification.
There is an equivalent Python3 module, with (as far as possible) the same
calling interface, at
http://cpansearch.perl.org/src/PJB/Term-Clui-1.69/py/TermClui.py
This is Term::Clui.pm version 1.69
WINDOW-SIZE¶
Term::Clui attempts to handle the WINCH signal. If the window size is changed,
then as soon as the user enters the next keystroke (such as ctrl-L) the
current question/response will be redisplayed to fit the new size.
The first line of the question, the one which will remain on-screen, is not
re-formatted, but is left to be dealt with by the width of the window.
Subsequent lines are split into blank-separated words which are filled into
the available width; lines beginning with white-space are treated as the
beginning of a new indented paragraph, individual words which will not fit
onto one line are truncated, and successive blank lines are collapsed into
one. If the question will not fit within the available rows, it is truncated.
If the available choice items in a
choose() overflow the
screen, the user is asked to enter "clue" letters, and as soon as
the items matching them will fit onto the screen they are displayed as a
choice.
SUBROUTINES¶
- ask( $question ); OR ask( $question, $default );
- Asks the user the question and returns a string answer, with no newline
character at the end. If the optional second argument is present, it is
offered to the user as a default. If the $question is
multi-line, the entry-field is at the top to the right of the first line,
and the subsequent lines are formatted within the screen width and
displayed beneath, as with choose.
For the user, left and right arrow keys move backward and forward through
the string, delete and backspace erase the previous character, ctrl-A
moves to the beginning, ctrl-E to the end, and ctrl-D or ctrl-X clear the
current string.
- ask_password( $question );
- Does the same with no echo, as used for password entry.
- ask_filename( $question );
- Uses Term::ReadLine::Gnu to provide filename-completion with the
Tab key, but also displays multi-line questions in the same way as
ask and choose do. This function was introduced in version
1.65.
- choose( $question, @list );
- Displays the question, and formats the list items onto the lines beneath
it.
If choose is called in a scalar context, the user can choose an item
using arrow keys (or hjkl) and Return, or cancel the choice with a
"q". choose then returns the chosen item, or
undefined if the choice was cancelled.
If choose is called in an array context, the user can also mark an
item with the SpaceBar. choose then returns the list of marked
items, (including the item highlit when Return was pressed), or an empty
array if the choice was cancelled.
A DBM database is maintained of the question and its chosen response. The
next time the user is offered a choice with the same question, if that
response is still in the list it is highlighted as the default; otherwise
the first item is highlighted. Different parts of the code, or different
applications using Term::Clui.pm can therefore exchange defaults
simply by using the same question words, such as "Which printer
?". Multiple choices are not remembered, as the danger exists that
the user might fail to notice some of the highlit items (for example, all
the items might not fit onto one screen).
The database ~/.clui_dir/choices or
$ENV{CLUI_DIR}/choices is available to be read or
written if lower-level manipulation is needed, and the EXPORT_OK
routines get_default($question) and set_default($question,
$choice) should be used for this purpose, as they handle DBM's problem
with concurrent accesses. The whole default database mechanism can be
disabled by CLUI_DIR=OFF if you really want to :-(
If the items won't fit on the screen, the user is asked to enter a substring
as a clue. As soon as the matching items will fit, they are displayed to
be chosen as normal. If the user pressed "q" at this choice,
they are asked if they wish to change their substring clue; if they reply
"n" to this, choose quits and returns undefined.
If the $question is multi-line, The first line is put at the top as usual
with the choices arranged beneath it; the subsequent lines are formatted
within the screen width and displayed at the bottom. After the choice is
made all but the first line is erased, and the first line remains
on-screen with the choice appended after it. You should therefore try to
arrange multi-line questions so that the first line is the question in
short form, and subsequent lines are explanation and elaboration.
- confirm( $question );
- Asks the question, takes "y", "n", "Y" or
"N" as a response. If the $question is multi-line, after the
response, all but the first line is erased, and the first line remains
on-screen with Yes or No appended after it; you should
therefore try to arrange multi-line questions so that the first line is
the question in short form, and subsequent lines are explanation and
elaboration. Returns true or false.
- edit( $title, $text ); OR edit( $filename );
- Uses the environment variable EDITOR ( or vi :-) Uses RCS if
directory RCS/ exists
- sorry( $message );
- Similar to warn "Sorry, $message\n";
- inform( $message );
- Similar to warn "$message\n"; except that it doesn't add
the newline at the end if there already is one, and it uses
/dev/tty rather than STDERR if it can.
- view( $title, $text ); OR view( $filename );
- If the $text is longer than a screenful, uses the
environment variable PAGER ( or less ) to display it. If it is one
or two lines it just omits the title and displays it. Otherwise it uses a
simple built-in routine which expects either "q" or
Return from the user; if the user presses Return the
displayed text remains on the screen and the dialogue continues after it,
if the user presses "q" the text is erased.
If there is only one argument and it's a filename, then the user's PAGER
displays it, except (since 1.65) if it's a .doc file, when either
wvText, antiword or catdoc is used to extract its
contents first.
- help_text( $mode );
- This returns a short help message for the user. If mode is
"ask" then the text describes the keys the user has available
when responding to an &ask question; If mode is
"multi" then the text describes the keys and mouse actions the
user has available when responding to a multiple-choice &choose
question; otherwise, the text describes the keys and mouse actions the
user has available when responding to a single-choice
&choose.
EXPORT_OK SUBROUTINES¶
The following routines are not exported by default, but are exported under the
ALL tag, so if you need them you should:
import Term::Clui qw(:ALL);
- beep()
- Beeps.
- timestamp()
- Returns a sortable timestamp string in "YYYYMMDD hhmmss"
form.
- get_default( $question )
- Consults the database ~/.clui_dir/choices or
$ENV{CLUI_DIR}/choices and returns the choice that
the user made the last time this question was asked. This is better than
opening the database directly as it handles DBM's problem with concurrent
accesses.
- set_default( $question, $new_default )
- Opens the database ~/.clui_dir/choices or
$ENV{CLUI_DIR}/choices and sets the default response
which will be offered to the user made the next time this question is
asked. This is better than opening the database directly as it handles
DBM's problem with concurrent accesses.
DEPENDENCIES¶
It requires Exporter, which is core Perl. It uses Term::ReadKey if it's
available; and uses Term::Size if it's available; if not, it tries
tput
before guessing 80x24.
ENVIRONMENT¶
The environment variable
CLUI_DIR can be used (by programmer or user) to
override
~/.clui_dir as the directory in which
choose() keeps its database of previous choices. The
whole default database mechanism can be disabled by
CLUI_DIR = OFF if
you really want to :-(
If either the LANG or the LC_TYPE environment variables contain the string
utf8 or
utf-8 (case insensitive), then
choose() and
inform() open
/dev/tty with a
utf8 encoding.
If the environment variable
CLUI_SPEAK is set or if
EDITOR is set
to
emacspeak, and if
flite is installed, then
Term::Clui
will use
flite to speak its questions and choices out loud.
If the environment variable
CLUI_MOUSE is set to
OFF then
choose() will not interpret mouse-clicks as making a
choice. The advantage of this is that the mouse can then be used to highlight
and paste text from this window as usual.
Term::Clui also consults the environment variables HOME, LOGDIR, EDITOR
and PAGER, if they are set.
EXAMPLES¶
These scripts using Term::Clui and Term::Clui::FileSelect are to be found in the
examples subdirectory of the build directory.
- linux_admin
- I use this script a lot at work, for routine system administration of
linux boxes, particularly Fedora and Debian. It includes crontab,
chkconfig, update-rc.d, visudo, vipw, starting and stopping daemons,
reconfiguring squid samba or apache, editing sysconfig or running any of
the system-config-* utilities, and much else.
- audio_stuff
- This script offers an arrow-key-and-return interface integrating
aplaymidi, cdrecord, cdda2wav, icedax, lame, mkisofs, muscript, normalize,
normalize-audio, mpg123, sndfile-play, timidity, wodim and so on, allowing
audio files to be ripped, burned, played, or converted between Muscript,
MIDI, WAV and MP3 formats.
- login_shell
- This script offers the naive user arrow-key-and-return access to a
text-based browser, a mail client, a news client, ssh and ftp and various
other stuff.
- test_script
- This is the test script, as used during development.
- choose
- This is a script which wraps Term::Clui::choose for use at the
shell-script level. It can either choose between command-line arguments,
or, with the -f (filter) option, between lines of STDIN, like grep.
A -m (multiple) option allows multiple-choice. This can be a very
useful script, and you may want to copy it into /usr/local/bin/ or
elsewhere in your PATH.
AUTHOR¶
Peter J Billam www.pjb.com.au/comp/contact.html
CREDITS¶
Based on some old perl 4 libraries,
ask.pl,
choose.pl,
confirm.pl,
edit.pl,
sorry.pl,
inform.pl and
view.pl, which were in turn based on some even older curses-based
programs in
C.
SEE ALSO¶
Term::Clui::FileSelect
Term::ReadKey
Term::Size
http://www.pjb.com.au/
http://invisible-island.net/xterm/ctlseqs/ctlseqs.html
http://search.cpan.org/~pjb
festival(1)
eflite(1)
espeak(1)
espeakup(1)
edbrowse(1)
emacspeak(1)
perl(1)
There is an equivalent Python3 module, with (as far as possible) the same
calling interface, at
http://cpansearch.perl.org/src/PJB/Term-Clui-1.69/py/TermClui.py