sub abc {
    my ($x) = @_;

    my $z;
    foreach my $y (@{ $x }) {
        # do xxx
        # on
        # lots
        # of 
        # lines
    }

    return $z;
}

##</code><code>##

+-- 14 lines: sub abc {

##</code><code>##

sub abc {
    my ($x) = @_;

    my $z;
+--- 7 lines:  foreach my $y (@{ $x }) {

    return $z;
}