Route.php

gistfile1.php

<?php

class Route
{
	protected $first_stop;

	protected $last_stop;

	// Assume getters and setters

	public function getStops()
	{
		do {
			if (is_null($stop)) {
				$stop = $this->getFirstStop();
			} else {
				$stop = $stop->next();
			}

			yield $stop;

		} while ($stop != $this->getLastStop());
	}
}