use Tk;

$bgcolor = 'yellow';

#you only use a variable 'reference' with specific attributes
$w = MainWindow->new(-background => $bgcolor, -title => 'Retrieving text');

$w->Button(-text => 'Retrieve',
		  -command => sub { getthetext() })->pack(-side => left);
$w->Button(-text => 'Clear',
		  -command => sub { clearthetext() })->pack(-side => right);
#note the difference between variable and variable 'reference'
$w->Label(-text => 'a label',
		  -background => $bgcolor, -textvariable => \$labeltext)->pack();
$w->Button(-text => 'Quit', -command => sub { exit() })->pack(-side => bottom);
#scrollbar is optional and on the 'east' side
$text = $w->Scrolled(Text, -scrollbars => 'oe',
		  -width => 40, -height => 10)->pack(-side => bottom);

MainLoop();

sub getthetext {
	#note the strange indices used to refer to text in Text widget
	$thetext = $text->get("1.0","end");
	@words = split(/\W+/,$thetext);
	$labeltext = $#words+1 . " words";
}

sub clearthetext {
	#note the strange indices used to refer to text in Text widget
	$text->delete("1.0","end");
}