perl -MO=Deparse -wle 'my %a = ( 0 => 1, y => 2, z => 4); while (my $m = each %a) { print $m }'

BEGIN { $^W = 1; }
BEGIN { $/ = "\n"; $\ = "\n"; }
my(%a) = (0, 1, 'y', 2, 'z', 4);
while (defined(my $m = each %a)) {
    print $m;
}