$ perl -MO=Deparse,-x9 ./mytest.pl

# Decomposition of the "for" loop:
while ($idx < 10) {
    print "$idx, $x, $y\n";
}
continue {
    ++$idx, $x += 2, $y += 3
}

# Decomposition of the "while" loop (essentially it's unchanged):
{
    my($idx, $x, $y) = (0, 0, 0);
    while ($idx < 10) {
        print "$idx, $x, $y\n";
    }
    continue {
        ++$idx;
        $x += 2;
        $y += 3;
    }
}
./mytest.pl syntax OK