package Foo;

sub bar {
  print $::bar, "\n";
}

package main;

$bar = "Hello, World!";
Foo::bar();

##</code><code>##

package Foo;

sub bar {
        print $baz, "\n";
}

package main;

$baz = "Hello, World";
foreach my $sym ( keys( %{*{::}} ) ) {
        *{"Foo::".$sym} = *{"::".$sym};
}
Foo::bar();