#!perl

use strict;
use warnings;
use Tk;

my $mw = tkinit(-width => 400, -height => 300,);
$mw->packPropagate(0);

my $default_text = 'Default...';
my $previous_input = '';
my $e = $mw->Entry(-text => $default_text)->pack(-fill => 'x', -expand => 0);
my $e2 = $mw->Entry(-text => 'dummy',)->pack(-fill => 'both', -expand => 1);

$e->bind('<FocusIn>' => [sub{
	my $entry		= shift;
	my $default		= shift;
	my $previous	= shift;
	
	if( $entry->get() eq $default_text ) {
		$entry->delete(0, 'end');
		$$previous = '';
	}else{
		$$previous = $entry->get();
	}
	
}, $default_text, \$previous_input]);

$e->bind('<FocusOut>' => [sub{
	my $entry		= shift;
	my $default		= shift;
	my $previous	= shift;
	
	if( $entry->get() eq '' ) {
		$entry->insert(0, $default_text);
		$$previous = '';
	}else{
		$$previous = $entry->get();
	}
	
	print "previous input is now set to [$$previous]\n";
	
}, $default_text, \$previous_input]);

$e->bind('<Escape>' => [sub{
	my $entry		= shift;
	my $mw			= shift;
	my $previous	= shift;

	if( $$previous ne '' and $entry->get() ne $previous_input ) {
		$entry->delete(0, 'end');
		$entry->insert(0, $$previous);
	}

	$mw->focus();
	
}, $mw, \$previous_input]);

$e->bind('<KeyPress>' => [sub{
	my $entry	= shift;
	my $key		= shift;
	
	return undef if $key eq 'Escape';
	
	print "$key was pressed\n";
	
}, Ev('K')]);

$mw->MainLoop();
exit(0);