use strict;
use Tk;

my $mw = MainWindow->new;

my $frame = $mw->Frame->pack;
$frame->Entry->pack(-side => 'left');
$frame->Button(-text => "Button")->pack(-side => 'left');

my $cv = $mw->Canvas()->pack();

$mw->bind( '<KeyPress-a>', sub { 
   my $widget = shift;
   print "$widget: ouch!\n";
}); 

MainLoop;