Term::UI - Term::ReadLine UI made easy
- use Term::UI;
- use Term::ReadLine;
- my $term = Term::ReadLine->new('brand');
- my $reply = $term->get_reply(
- prompt => 'What is your favourite colour?',
- choices => [qw|blue red green|],
- default => blue,
- );
- my $bool = $term->ask_yn(
- prompt => 'Do you like cookies?',
- default => 'y',
- );
- my $string = q[some_command -option --no-foo --quux='this thing'];
- my ($options,$munged_input) = $term->parse_options($string);
- ### don't have Term::UI issue warnings -- default is '1'
- $Term::UI::VERBOSE = 0;
- ### always pick the default (good for non-interactive terms)
- ### -- default is '0'
- $Term::UI::AUTOREPLY = 1;
- ### Retrieve the entire session as a printable string:
- $hist = Term::UI::History->history_as_string;
- $hist = $term->history_as_string;
Term::UI
is a transparent way of eliminating the overhead of having
to format a question and then validate the reply, informing the user
if the answer was not proper and re-issuing the question.
Simply give it the question you want to ask, optionally with choices
the user can pick from and a default and Term::UI
will DWYM.
For asking a yes or no question, there's even a shortcut.
Term::UI
places itself at the back of the Term::ReadLine
@ISA
array, so you can call its functions through your term object.
Term::UI
uses Term::UI::History
to record all interactions
with the commandline. You can retrieve this history, or alter
the filehandle the interaction is printed to. See the
Term::UI::History
manpage or the SYNOPSIS
for details.
get_reply
asks a user a question, and then returns the reply to the
caller. If the answer is invalid (more on that below), the question will
be reposed, until a satisfactory answer has been entered.
You have the option of providing a list of choices the user can pick from
using the choices
argument. If the answer is not in the list of choices
presented, the question will be reposed.
If you provide a default
answer, this will be returned when either
$AUTOREPLY
is set to true, (see the GLOBAL VARIABLES
section further
below), or when the user just hits enter
.
You can indicate that the user is allowed to enter multiple answers by
toggling the multi
flag. Note that a list of answers will then be
returned to you, rather than a simple string.
By specifying an allow
hander, you can yourself validate the answer
a user gives. This can be any of the types that the Params::Check allow
function allows, so please refer to that manpage for details.
Finally, you have the option of adding a print_me
argument, which is
simply printed before the prompt. It's printed to the same file handle
as the rest of the questions, so you can use this to keep track of a
full session of Q&A with the user, and retrieve it later using the
Term::UI->history_as_string
function.
See the EXAMPLES
section for samples of how to use this function.
Asks a simple yes
or no question to the user, returning a boolean
indicating true
or false
to the caller.
The default
answer will automatically returned, if the user hits
enter
or if $AUTOREPLY
is set to true. See the GLOBAL VARIABLES
section further below.
Also, you have the option of adding a print_me
argument, which is
simply printed before the prompt. It's printed to the same file handle
as the rest of the questions, so you can use this to keep track of a
full session of Q&A with the user, and retrieve it later using the
Term::UI->history_as_string
function.
See the EXAMPLES
section for samples of how to use this function.
parse_options
will convert all options given from an input string
to a hash reference. If called in list context it will also return
the part of the input string that it found no options in.
Consider this example:
- my $str = q[command --no-foo --baz --bar=0 --quux=bleh ] .
- q[--option="some'thing" -one-dash -single=blah' arg];
- my ($options,$munged) = $term->parse_options($str);
- ### $options would contain: ###
- $options = {
- 'foo' => 0,
- 'bar' => 0,
- 'one-dash' => 1,
- 'baz' => 1,
- 'quux' => 'bleh',
- 'single' => 'blah\'',
- 'option' => 'some\'thing'
- };
- ### and this is the munged version of the input string,
- ### ie what's left of the input minus the options
- $munged = 'command arg';
As you can see, you can either use a single or a double -
to
indicate an option.
If you prefix an option with no- and do not give it a value, it
will be set to 0.
If it has no prefix and no value, it will be set to 1.
Otherwise, it will be set to its value. Note also that it can deal
fine with single/double quoting issues.
Convenience wrapper around Term::UI::History->history_as_string
.
Consult the Term::UI::History
man page for details.
The behaviour of Term::UI can be altered by changing the following global variables:
This controls whether Term::UI will issue warnings and explanations as to why certain things may have failed. If you set it to 0, Term::UI will not output any warnings. The default is 1;
This will make every question be answered by the default, and warn if there was no default provided. This is particularly useful if your program is run in non-interactive mode. The default is 0;
This holds the string that will be printed when the user makes an
invalid choice.
You can override this string from your program if you, for example,
wish to do localization.
The default is Invalid selection, please try again:
This is the filehandle all the print statements from this module
are being sent to. Please consult the Term::UI::History
manpage
for details.
This defaults to *STDOUT
.
- ### ask a user (with an open question) for their favourite colour
- $reply = $term->get_reply( prompt => 'Your favourite colour? );
which would look like:
- Your favourite colour?
and $reply
would hold the text the user typed.
- ### now provide a list of choices, so the user has to pick one
- $reply = $term->get_reply(
- prompt => 'Your favourite colour?',
- choices => [qw|red green blue|] );
which would look like:
- 1> red
- 2> green
- 3> blue
- Your favourite colour?
$reply
will hold one of the choices presented. Term::UI
will repose
the question if the user attempts to enter an answer that's not in the
list of choices. The string presented is held in the $Term::UI::INVALID
variable (see the GLOBAL VARIABLES
section for details.
- ### provide a sensible default option -- everyone loves blue!
- $reply = $term->get_reply(
- prompt => 'Your favourite colour?',
- choices => [qw|red green blue|],
- default => 'blue' );
which would look like:
- 1> red
- 2> green
- 3> blue
- Your favourite colour? [3]:
Note the default answer after the prompt. A user can now just hit enter
(or set $Term::UI::AUTOREPLY
-- see the GLOBAL VARIABLES
section) and
the sensible answer 'blue' will be returned.
- ### allow the user to pick more than one colour and add an
- ### introduction text
- @reply = $term->get_reply(
- print_me => 'Tell us what colours you like',
- prompt => 'Your favourite colours?',
- choices => [qw|red green blue|],
- multi => 1 );
which would look like:
- Tell us what colours you like
- 1> red
- 2> green
- 3> blue
- Your favourite colours?
An answer of 3 2 1 would fill @reply
with blue green red
- ### pose an open question, but do a custom verification on
- ### the answer, which will only exit the question loop, if
- ### the answer matches the allow handler.
- $reply = $term->get_reply(
- prompt => "What is the magic number?",
- allow => 42 );
Unless the user now enters 42
, the question will be reposed over
and over again. You can use more sophisticated allow
handlers (even
subroutines can be used). The allow
handler is implemented using
Params::Check
's allow
function. Check its manpage for details.
- ### ask a user if he likes cookies. Default to a sensible 'yes'
- ### and inform him first what cookies are.
- $bool = $term->ask_yn( prompt => 'Do you like cookies?',
- default => 'y',
- print_me => 'Cookies are LOVELY!!!' );
would print:
- Cookies are LOVELY!!!
- Do you like cookies? [Y/n]:
If a user then simply hits enter
, agreeing with the default,
$bool
would be set to true
. (Simply hitting 'y' would also
return true
. Hitting 'n' would return false
)
We could later retrieve this interaction by printing out the Q&A history as follows:
- print $term->history_as_string;
which would then print:
- Cookies are LOVELY!!!
- Do you like cookies? [Y/n]: y
There's a chance we're doing this non-interactively, because a console is missing, the user indicated he just wanted the defaults, etc.
In this case, simply setting $Term::UI::AUTOREPLY
to true, will
return from every question with the default answer set for the question.
Do note that if AUTOREPLY
is true, and no default is set, Term::UI
will warn about this and return undef.
Params::Check
, Term::ReadLine
, Term::UI::History
Please report bugs or other issues to <bug-term-ui@rt.cpan.org<gt>.
This module by Jos Boumans <kane@cpan.org>.
This library is free software; you may redistribute and/or modify it under the same terms as Perl itself.