use strict;
use warnings;
use Tk;
use Tk::ROText;
my $cancel = 0;

my $mw = MainWindow -> new (-title => "  loop test");
$mw -> withdraw;
$mw -> minsize (qw(700 400));

my $status = $mw -> Scrolled ("ROText",
			-scrollbars => 'e',
			-background => 'white',
			) ->pack(
			-expand => 1,
			-fill => 'both',
			);

$status -> configure(-wrap => 'word');

my $exit = $mw -> Button (
			-text , 'Exit',
			-command, \&my_exit,
			) -> pack (-side, 'left');

my $start = $mw -> Button (
			-text , 'Start',
			-command, \&start,
			) -> pack (-side, 'right');

$mw -> Popup;
$mw -> focus;

MainLoop();

sub start {
	$cancel = 0;

	$start -> configure (
			-state => 'disabled',
			-relief => 'sunken');

	$exit -> configure (
			-text => 'Cancel',
			-command => \&cancel);

	for (1..100) {
#          last if $cancel;
           output ("$_\n");
           sleep 2;
	}
	done();
}

sub cancel {
	output ("Cancelling...\n");
	$cancel =1;
}

sub my_exit {
	exit();
}

sub done {
	$start -> configure (
			-state => 'normal',
			-relief => 'raised');
	$exit -> configure (
			-text => "Exit",
			-command => \&my_exit);

	output ("Done.\n");
}

sub output {
	my $text = $_[0];
	$status->insert('end', "$text");
	$status -> see ('end');
	$mw->update;
}