La classe Generator

Unlike return, yield can be used anywhere within a function so logic can flow more naturally. Take for example the following Fibonacci generator:
<?php
function fib($n)
{
 $cur = 1;
 $prev = 0;
 for ($i = 0; $i < $n; $i++) {
 yield $cur;
 $temp = $cur;
 $cur = $prev + $cur;
 $prev = $temp;
 }
}
$fibs = fib(9);
foreach ($fibs as $fib) {
 echo " " . $fib;
}
// prints: 1 1 2 3 5 8 13 21 34