I must be getting old. I distinctly remember learning that lesson when Perl 5 was freshly minted. The grammar must have been "improved" since then. You are right about the latter for sure; how many times do I say

my ($x,$y,$z)= @_;
</code?

So the <code>my ($x)
[download]

vs (my $x) must be (or have been) something more subtle.