https://twitter.com/devnic_/status/1504194463383576576

foreach.php

<?php

function check(int &$val): Generator {
  while ($val === 0) {
    yield 1;
  }
}

$var = 0;
$loop = 0;
foreach (check($var) as $dummy) {
  // do something cool here
  echo 'Loop: ', $loop, PHP_EOL;

  // when should we leave?
  if (++$loop > 10) {
    $var = 1;
  }
}