Generators in HHVM and PHP

a.php

<?php
 
function xs() {
    $i = 0;
    while (true) {
        yield $i++;
    }
}
 
$xs = xs();
 
var_dump($xs->valid());
var_dump($xs->current());

b.php

<?php
 
function xs() {
    $i = 0;
    while (true) {
        yield $i++;
    }
}
 
$xs = xs();
 
var_dump($xs->next());
var_dump($xs->valid());
var_dump($xs->current());

c.php

<?php
 
function xs() {
    $i = 0;
    while (true) {
        yield $i++;
    }
}
 
$xs = xs();
 
$xs->send(42);
var_dump($xs->next());
var_dump($xs->valid());
var_dump($xs->current());