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Ask-0.015
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/ Ask

NAME

Ask - ask your users about stuff

SYNOPSIS

Object-oriented style:

   use Ask;
   
   my $ask = Ask->detect;
   
   if ($ask->question(text => "Are you happy?")
   and $ask->question(text => "Do you know it?")
   and $ask->question(text => "Really want to show it?")) {
      $ask->info(text => "Then clap your hands!");
   }

Functional style:

   use Ask ':all';
   
   if (question("Are you happy?")
   and question("Do you know it?")
   and question("Really want to show it?")) {
      info("Then clap your hands!");
   }

DESCRIPTION

The Ask suite is a set of modules for interacting with users; prompting them for information, displaying messages, warnings and errors, etc.

There are already countless CPAN modules for doing this sort of thing, but what sets Ask apart from them is that Ask will detect how your script is being run (in a terminal, headless, etc) and choose an appropriate way to interact with the user.

Class Methods

Ask->instance

Singleton pattern. Can also be passed an argument to use it as a setter.

Ask->detect(%arguments)

A constructor, sort of. It inspects the program's environment and returns an object that implements the Ask API (see below).

Backend-specific arguments can be provided:

  my $ask = Ask->detect(
    %common_args,
    'Ask::STDIO'  => \%stdio_args,
    'Ask::Zenity' => \%zenity_args,
  );

Note that these objects don't usually inherit from Ask, so the following will typically be false:

   my $ask = Ask->detect(%arguments);
   $ask->isa("Ask");

Instead, check:

   my $ask = Ask->detect(%arguments);
   $ask->DOES("Ask::API");
Ask->backends

Returns a list of available backends. Each backend is a Perl class name. Some of the backends may be available (i.e. installed and able to be compiled) without being usable under current circumstances (e.g. the Gtk2 backend is available but cannot be used because no X server is running). To check usability, instantiate the class and call is_usable on the instance.

The list is sorted in "quality" order, best to worst, though quality is subjective.

Ask->plugins

The same as Ask->backends, but doesn't check that each result is a loadable Perl class, and doesn't sort them in any particular order.

The Ask API

Objects returned by the detect method implement the Ask API. This section documents that API.

The following methods are provided by objects implementing the Ask API. They are largely modeled on the interface for GNOME Zenity.

info(text => $text, %arguments)

Display a message to the user.

Setting the argument no_wrap to true can be used to hint that line wrapping should be avoided.

The lang argument can be used to indicate the language of the text as an ISO 639-1 code (e.g. "en" for English). Not all objects implementing the Ask API will pay attention to this hint, so don't be too surprised to see text in French with an English "OK" button underneath!

warning(text => $text, %arguments)

Display a warning to the user.

Supports the same arguments as info.

error(text => $text, %arguments)

Display an error message (not necessarily fatal) to the user.

Supports the same arguments as info.

entry(%arguments)

Ask the user to enter some text. Returns that text.

The text argument is supported as a way of communicating what you'd like them to enter. The hide_text argument can be set to true to hint that the text entered should not be displayed on screen (e.g. password input).

The default argument can be used to supply a default return value if the user cannot be asked for some reason (e.g. running on an unattended terminal).

The lang argument can be used to indicate the language of the text as an ISO 639-1 code (e.g. "en" for English).

question(text => $text, %arguments)

Ask the user to answer an affirmative/negative question (i.e. OK/cancel, yes/no) defaulting to affirmative. Returns boolean.

The text argument is the text of the question; the ok_label argument can be used to set the label for the affirmative button; the cancel_label argument for the negative button.

The default argument can be used to supply a default return value if the user cannot be asked for some reason (e.g. running on an unattended terminal).

The lang argument can be used to indicate the language of the text as an ISO 639-1 code (e.g. "en" for English).

file_selection(%arguments)

Ask the user for a file name. Returns the file name. No checks are made to ensure the file exists.

The multiple argument can be used to indicate that multiple files may be selected (they are returned as a list); the directory argument can be used to hint that you want a directory.

The default argument can be used to supply a default return value if the user cannot be asked for some reason (e.g. running on an unattended terminal). If multiple is true, then this must be an arrayref.

Until version 0.011, returned values are strings. Thereafter, returned values are Path::Tiny objects.

single_choice(text => $text, choices => \@choices)

Asks the user to select a single option from many choices.

For example:

   my $answer = $ask->single_choice(
      text    => "If a=1, b=2. What is a+b?",
      choices => [
         [ A => 12 ],
         [ B => 3  ],
         [ C => 2  ],
         [ D => 42 ],
         [ E => "Fish" ],
      ],
   );

The choices are identifier => label pairs. The identifiers are not necessarily displayed to the user making the choice; the labels are. The function returns the identifier for the chosen option.

The default argument can be used to supply a default return value if the user cannot be asked for some reason (e.g. running on an unattended terminal).

The lang argument can be used to indicate the language of the text and labels as an ISO 639-1 code (e.g. "en" for English).

multiple_choice(text => $text, choices => \@choices)

Asks the user to select zero or more options from many choices.

   my @ingredients = $ask->multiple_choice(
      text    => "What do you want on your pizza?",
      choices => [
         [ cheese    => 'Cheese' ],
         [ tomato    => 'Tomato' ],
         [ ham       => 'Ham'    ],
         [ pineapple => 'Pineapple' ],
         [ chocolate => 'Chocolate' ],
      ],
   );

Returns list of identifiers.

The default argument can be used to supply a default return value if the user cannot be asked for some reason (e.g. running on an unattended terminal). It must be an arrayref.

The lang argument can be used to indicate the language of the text and labels as an ISO 639-1 code (e.g. "en" for English).

If you wish to create your own implementation of the Ask API, please read Ask::API for more information.

Extending Ask

Implementing Ask::API allows you to extend Ask to other environments.

To add extra methods to the Ask API you may use Moo roles:

   {
      package AskX::Method::Password;
      use Moo::Role;
      sub password {
         my ($self, %o) = @_;
         $o{hide_text} //= 1;
         $o{text}      //= "please enter your password";
         $self->entry(%o);
      }
   }
   
   my $ask = Ask->detect(traits => ['AskX::Method::Password']);
   say "GOT: ", $ask->password;

Export

You can optionally export the Ask methods as functions. The functions behave differently from the object-oriented interface in one regard; if called with one parameter, it's taken to be the "text" named argument.

   use Ask qw( question info );
   
   if (question("Are you happy?")
   and question("Do you know it?")
   and question("Really want to show it?")) {
      info("Then clap your hands!");
   }

Ask uses Sub::Exporter::Progressive, so exported functions may be renamed:

   use Ask
      question => { -as => 'interrogate' },
      info     => { -as => 'notify' },
   ;

I18n

It is strongly recommended that you pass a lang argument with each method call. Not all backends yet pay attention to it.

See also AskX::AutoLang as a way to avoid passing lang => "fu" to every single method call!

ENVIRONMENT

The PERL_ASK_BACKEND environment variable can be used to influence the outcome of Ask->detect. Indeed, it trumps all other factors. If set, it should be a full class name.

If either of the AUTOMATED_TESTING or PERL_MM_USE_DEFAULT environment variables are set to true, the Ask::Fallback backend will automatically be used.

BUGS

Please report any bugs to http://rt.cpan.org/Dist/Display.html?Queue=Ask.

SEE ALSO

Terminal backends:

GUI backends:

Backends which perform no real user interaction:

  • Ask::Callback - implementation for testing; redirects input and output to callback functions.

  • Ask::Fallback - returns default answers; for scripts running unattended.

See Ask::API for documentation of API internals.

See Ask::Question for an alternative way of using Ask.

Similar modules: IO::Prompt, IO::Prompt::Tiny and many others.

AUTHOR

Toby Inkster <tobyink@cpan.org>.

COPYRIGHT AND LICENCE

This software is copyright (c) 2012-2013, 2020 by Toby Inkster.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.

DISCLAIMER OF WARRANTIES

THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.