Just a small note - local() automatically undef()ines whatever gets passed to it.

$foo = "I am a package var, yes I am";
{
    local $foo;
    print "\$foo is no more\n" if not defined $foo;
}
print qq(\$foo returns!\n) if defined $foo;

__output__

$foo is no more
$foo returns!
[download]

HTH

broquaint