#!/usr/bin/env perl

use strict;
use warnings;

print "Before assignment: \$xyz ", (exists($::{'xyz'}) ? 'exists' : 'does not exist'), "\n";

eval '$main::xyz = 42;';

print "After assignment: \$xyz ", (exists($::{'xyz'}) ? 'exists' : 'does not exist'), "\n";
eval 'print $main::xyz, "\n";'; # Prints 42.
eval 'undef $main::xyz;';

print "After undef: \$xyz ", (exists($::{'xyz'}) ? 'exists' : 'does not exist'), "\n";

##</code><code>##

Before assignment: $xyz does not exist
After assignment: $xyz exists
42
After undef: $xyz exists