Custom generator classes with IteratorAggregate

foo.php

<?php

class ForLoop implements IteratorAggregate
{

    public $from = 0, $to, $step = 1;

    function getIterator() {
        for($i = $this->from; $i <= $this->to; $i += $this->step) {
            yield $i;
        }
    }

}


$f = new ForLoop;
$f->from = 3;
$f->to = 9;
$f->step = 2;

foreach($f as $number) {
    echo "$number things, ha ha ha!\n";
}