reverse_linked_list.php

<?php

function reverse_linked_list(Node &$node): void
{
	for (
		$current = $node,
		$previous = null,
		$following = $current->next;
		$current !== null;
		$previous = $current,
		$current = $following,
		$following = $current->next ?? null
	) {
		$current->next = $previous;
		$node = $current;
	}
}