Inform Module

Provides a GTK dialog box from a Raku program. It is easy to add buttons and simple entry widgets to the box. Information is returned to a capture object.

The module is a stripped down version of the gtk-simple module minus all the unused widgets.

On Linux distributions, the GTK library is almost guaranteed, but there will be an error unless the dev library (something like libgtk-dev) is installed.

On Windows, GTK is likely not installed. A build check is incorporated. If it fails, the GTK library has not been found. A place to look for installation help is the GTK project installation page.

The example uses the inform procedural style subroutine, but the object based style can be seen by looking at inform.

For example

#!/usr/bin/env raku
use v6.c;
use Informative;
=comment
  Show a box with some information on screen, has a destructor x on window, but removes itself after 10s.
  Notice that there is a countdown time for information.
  The string can be marked up with pango markup. 
  
inform( 'This is <span color="blue">blue</span> and <span color="red" weight="bold">red</span> information'  );
=comment
  The label shown in the box is 'This is blue and red information' (with colours).
  The default title is 'Inform'

=comment 
  New title and for a shorter time (5s), note that a timer of 0 is forever.
  
my $popup = inform( 'Shorter time span for me', :timer(5), :title<More> );
=comment
  The title of the window is now 'More'.
  The C<inform> subroutine returning an instance of the C<Informing> class, which is then shown.

=comment 
  The C<Informing> object in $popup can be reused with changes in message, countdown and timer.
  The title, buttons and entries are only allowed when creating a new C<Informing> object.
  The C<show> method is available in the C<Informing> object.
  
$popup.show( 'See no countdown, but timer is unchanged', :!show-countdown );
=comment
  The timer is now no longer showing

=comment
  The colour (in USA color) of the countdown can be changed from the default 'red' to any colour accepted by Pango.

$popup = inform( 'I prefer the blues', :timer(5), :countdown-colour<blue> );

=comment
  Oops blues originated in the USA

$popup = inform( 'The blues spread in the movies', :timer(5), :countdown-color<#9c5d7c> );

=comment
  Add some buttons
  
my $gui-response = inform( 'Do you want to continue?', 
    :buttons( OK=>'OK',b2=>'Not on your life', 'Cancel'=> "I don't want to")
    ); 
say "We have {$gui-response.response} ";
=comment
  The box contains the label 'Do you want to continue' and has three buttons 
  with labels 'OK', 'Not on your life' and "I don't want to"
  The name of the button clicked (OK, b2, Cancel) is printed

=comment
  Access response 
  
say 'Ok continuing' if $gui-response.response eq 'OK';
=comment
  Check other responses
  
say 'I am heedful of your desires' if $gui-response.response ~~ any <b2 Cancel>;
=comment
  Check whether the destruct x was clicked
  
say 'So you don\'t like the options I gave you, huh?' if $gui-response.response eq '_destruct';

=comment
  Add an entry widget and some buttons
  Note that if an entry widget is requested, but no buttons are requested, then
  Cancel and OK are added automatically. 
  An entry widget without buttons is not allowed (design decision)
  
my $data = inform('Give me some things to clean',
    :buttons(Cancel => 'None today', :Response('Here you go')),
    :entries( Laundry => 'Enter your laundry list',)
    );
=comment
  The box contains a label, then one or more entry widgets, then a row of boxes.
  The formatting will depend on gtk defaults.
  NOTE: 'buttons' and 'entries' each expect a list of pairs, not a hash. So the comma
  after '...laundry list' and before the bracket is essential to force a list. With
  two elements, as in the buttons expression, a list already forms. 

if $data.response eq 'Cancel' { say 'Great, more free time for me' }
elsif $data.response eq 'Response' {
  for $data.data<Laundry>.comb(/\w+/) { say "I will clean your $_" }
}

=comment
    An entry widget can mask input, as in password requests, by adding _pw or -pw onto the
    name of the entry.

my $login = inform('Please supply your username and password', 
    :entries(un => 'User name', pw_pw => 'Password')
    );

if $login.response eq 'OK' { say "user name is \<{$login.data<un>}> and password is \<{$login.data<pw_pw>}>" };

A design goal his to keep the module as simple and small as possible, and to result in a popup that is intuitive to the user. Hence:

• A buttonless lable has a countdown timer to show when it is disappearing.
• Entries are not permitted without buttons. In principle, gtk_entry has an Activate signal that could be attached to an Entry widget (when text is ended with a Return key). However, a dialog box with only an entry form with no obvious way to respond would be difficult to understand.
• All Buttons act in the same way: if Entry widgets are present, the text is stored in the data attribute, and the dialog box is closed. It is for the user to determine how to handle the data.
• A dialog box that is destroy by clicking on the x will not store Entry data.

There are no limits in the module on the number of buttons or entry widgets that can be added. However, in practice, the reliance on gtk default formating will probably quickly make the inform box look ugly.

If more sophisticated button behaviours, different widgets or formatting are required, look at the Gtk::Simple module.