sub name {
        {
                package For_name_internal_use;
                use overload '""' => sub { $_[0]->() }, fallback => 1;
        }
        return bless sub {
                my $in_copy;
                for (my $stack = 2; ! $in_copy and my @caller = caller($stack); ++$stack) {
                        $in_copy = 1 if $caller[3] && $caller[3] eq 'whatever::copy';
                }

                if ($in_copy) {
                        return 'some result to be used in whatever::copy';
                } else {
                        return 'some result to be used outside of whatever::copy';
                }
        }, 'For_name_internal_use';
}