#!perl

use strict;
use warnings;
use Tk;

my $mw = tkinit();

my $toplevel = $mw->Toplevel();

$mw->Button(-text => 'show/hide', -command => [sub{ show_hide(@_); }, $toplevel],)->pack();

$mw->MainLoop();

sub show_hide {
        my $toplvl = shift;
        
        if( $toplvl->viewable ) {
                print "hide widget\n";
                $toplvl->UnmapWindow();
        }else{
                print "display widget\n";
                $toplvl->MapWindow();
        }
        
} # /show_hide