use Tk;
use strict;

my $mw = MainWindow->new();

my $button1 = $mw->Button(-text => "on release 1")->pack();
$button1->bind('<ButtonRelease 1>' => \&doit1 );

my $msg = "pressed 2";
my $button2 = $mw->Button(-text =>  "on realease 2")->pack();
$button2->bind('<ButtonRelease 1>' => sub { \&doit2($msg) } );

my $button3 = $mw->Button(-text => "on release 3")->pack();
$button3->bind('<ButtonRelease 1>' => [\&doit3]);

my $msg1 = "pressed 4";
my $button4 = $mw->Button(-text => "on release 4")->pack();
$button4->bind('<ButtonRelease 1>' => [\&doit4, $msg1]);

MainLoop;

sub doit1(){
   print "pressed 1\n";
}
sub doit2(){
   my $msg = shift;
   print "$msg\n";
}
sub doit3(){
   print "pressed 3\n";
}
sub doit4(){
   shift;
   my $msg = shift;
   print "$msg\n";
}


##</code><code>##

pressed 1
pressed 2
pressed 3
pressed 4