Hello Monkers!
Some days ago I found online the excellent Curses::UI "graphic" library, so I started to write a simple text editor, using this code (one of the examples in the "example" path):

use strict;
use Curses;
use Cwd;
 
use Curses::UI;
 
# Load an initial file if an argument given on the command line.
# If the file can't be found, assume that this is a new file.
my $text = "";
my $currentfile = shift;
if (defined $currentfile and -f $currentfile) 
{
        open F, "<$currentfile" or die "Can't read $currentfile: $!\n"
+;
        while (<F>) { $text .= $_ }
        $currentfile = $currentfile;
        close F;
}
 
# We don't want STDERR output to clutter the screen.
#
# Hint: If you need STDERR, write it out to a file and put 
# a tail on that file to see the STDERR output. Example:
#open STDERR, ">>/tmp/editor_errors.$$";
open STDERR, ">/dev/null";
 
# --------------------------------------------------------------------
+--
# Menu definition
# --------------------------------------------------------------------
+--
 
my @menu = (
  { -label => 'File', 
    -submenu => [
      { -label => 'Open file ^O', -value => \&open_dialog  },
      { -label => 'Save file ^S', -value => \&save_dialog  },
      { -label => 'Exit      ^Q', -value => \&exit_dialog  }
    ]
  },
  { -label => 'Help', 
    -submenu => [
      { -label => 'About editor', -value => \&about_dialog }
    ]
  } 
);
 
# --------------------------------------------------------------------
+--
# Create widgets
# --------------------------------------------------------------------
+--
 
# Create the root. Everything else will be built up from here.
use Curses::UI;
my $cui = new Curses::UI ( 
        -clear_on_exit => 1 
);
 
# Add the menu to the root.
my $menu = $cui->add(
        'menu','Menubar', 
        -menu => \@menu,
);
 
# Create the screen for the editor.
my $screen = $cui->add(
        'screen', 'Window',
        -padtop          => 1, # leave space for the menu
        -border          => 0,
        -ipad            => 0,
);
 
# We add the editor widget to this screen.
my $editor = $screen->add(
        'editor', 'TextEditor',
        -border          => 1,
        -padtop          => 0,       
        -padbottom       => 3,
        -showlines       => 0,
        -sbborder        => 0,
        -vscrollbar      => 1,
        -hscrollbar      => 1,
        -showhardreturns => 0,
        -wrapping        => 0, # wrapping slows down the editor :-(
        -text            => $text,
);
 
# There is no need for the editor widget to loose focus, so
# the "loose-focus" binding is disabled here. This also enables the
# use of the "TAB" key in the editor, which is nice to have.
$editor->clear_binding('loose-focus');
 
# Help information for the user. 
$screen->add(
        'help', 'Label',
        -y               => -2,
        -width           => -1,
        -reverse         => 1,
        -paddingspaces   => 1,
        -text            => 
              " ^Q Quit from the program ^S save file"
            . " ^W toggle wrapping\n"
            . " ^X Open the menu         ^O open file"
            . " ^R toggle hard returns viewing",
);
 
# --------------------------------------------------------------------
+--
# Callback routines
# --------------------------------------------------------------------
+--
         
sub open_dialog()
{
        my $file = $cui->loadfilebrowser( 
                -file         => $currentfile,
        );
 
        if (defined $file) 
        {
                if (open F, "<$file") {
                    my $text = "";
                    while (<F>) { $text .= $_ }
                    close F;
                    $editor->text($text);
                    $editor->cursor_to_home;
                    $currentfile = $file;
                } else { 
                    $cui->error(-message => "Can't read file \"$file\"
+:\n$!");
                }
        }
}
 
sub save_dialog()
{
 
        my $file = $cui->savefilebrowser(
                -file         => $currentfile,
        );
        return unless defined $file;
 
        if (open F, ">$file") {
            print F $editor->text;
            if (close F) {
                $cui->dialog(-message => "File \"$file\"\nsuccessfully
+ saved");
                $currentfile = $file;
            } else {
                $cui->error(-message => "Error on closing file \"$file
+\":\n$!");
            }
        } else {
            $cui->error(-message => "Can't write to $file:\n$!");
        }
}
 
sub about_dialog()
{
        $cui->dialog(
                -title => 'About editor',
                -message => "Program : Curses::UI Editor\n"
                          . "Author  : Maurice Makaay\n"
                          . "\n"
                          . "The sole purpose of this editor\n"
                          . "is the demonstration of my perl\n"
                          . "Curses::UI widget set."
        );
}
                 
sub exit_dialog()
{
        my $return = $cui->dialog(
                        -title     => "Are you sure???", 
                        -buttons   => ['yes', 'no'],
                        -message => "Do you really want to quit?"
        );
 
        exit(0) if $return;
}
 
 
# --------------------------------------------------------------------
+--
# The main loop of the program
# --------------------------------------------------------------------
+--
 
 
$cui->set_binding(\&exit_dialog, "\cQ", "\cC");
$cui->set_binding(\&save_dialog, "\cS");
$cui->set_binding(\&open_dialog, "\cO");
$cui->set_binding(sub {shift()->getobj('menu')->focus}, "\cX", KEY_F(1
+0));
$cui->set_binding(sub {
        my $cui = shift;
        $cui->layout;
        $cui->draw;
}, "\cL");
 
 
# Bring the focus to the editor widget.
$editor->focus;
 
$cui->mainloop;
[download]

Now I would like to add a global word auto-complete function which, given an array of similar words, clicking <TAB> autocomplete the current user- typed word. Online I found this:

https://metacpan.org/pod/Term::Complete
[download]

but unfortunately it doesn't work if I put this at the top of the script

$input = Complete('prompt_string', \@completion_list);
[download]

Thanks,
Edoardo Mantovani, 2020