Online PHP editor | output for XDhQ9

<?php function generator(): iterable { $count = 0; while (true) { echo 'About to yield: ', $count, \PHP_EOL; yield $count++; echo 'Resumed', \PHP_EOL; } } function limit(\Iterator $inner, int $count) { if ($count <= 0) return; $i = 0; $inner->rewind(); if (!$inner->valid()) return; yield $inner->key() => $inner->current(); // pre-increment because we already yielded once while (++$i < $count) { $inner->next(); if ($inner->valid()) { yield $inner->key() => $inner->current(); } else { return; } } } echo "Construct:\n"; $i = limit(generator(), 3); echo "Rewind:\n"; $i->rewind(); echo "\n1st iteration\n"; echo $i->valid() ? "Valid\n" : "Not valid\n"; echo "Current value: ", $i->current(), "\n"; $i->next(); echo "\n2nd iteration\n"; echo $i->valid() ? "Valid\n" : "Not valid\n"; echo "Current value: ", $i->current(), "\n"; $i->next(); echo "\n3rd iteration\n"; echo $i->valid() ? "Valid\n" : "Not valid\n"; echo "Current value: ", $i->current(), "\n"; $i->next(); echo "\n4th iteration\n"; echo $i->valid() ? "Valid\n" : "Not valid\n"; echo "Current value: ", $i->current(), "\n"; $i->next(); echo "\n5th iteration\n"; echo $i->valid() ? "Valid\n" : "Not valid\n"; echo "Current value: ", $i->current(), "\n"; $i->next();