#!perl

package MyTest;

use Moose;
use Tk;

has 'mw' => (is => 'rw', isa => 'Any');
has 'some_val' => (is => 'rw', isa => 'Str');

my $var = '';

sub new {
    my $class = shift;
    my $self = bless({}, $class);
    
    # -- init GUI
    my $mw = Tk::MainWindow->new();
    $self->mw($mw);
    
    $mw->Entry(
        # geht nicht, weil keine Variable:
        #-textvariable => \$self->some_val,
        
        # geht:
        -textvariable => \$var,
    )->pack();
    
    $mw->Label(
        -textvariable => \$var,
    )->pack();
    
    return $self;
} # /new

sub run {
    my $self = shift;
    $self->mw->MainLoop();
    return;
} # /run

1; # /MyTest

use strict;
use warnings;

my $app = MyTest->new();
$app->run();
exit(0);