while ()  { $_++; last if $_ == 1000; }
while (1) { $_++; last if $_ == 1000; }
for (;;)  { $_++; last if $_ == 1000; }
##</code><code>##

for (;;) {
    ++$_;
    last if $_ == 1000;
}
for (;;) {
    ++$_;
    last if $_ == 1000;
}
for (;;) {
    ++$_;
    last if $_ == 1000;
}
test.pl syntax OK