zero_to_one.php

<?php

function mygenerator() {
    yield 0;
    yield 1;
    yield 2;
    yield 3;
}

$g = mygenerator();
var_dump($g->current()); # int(0)
$g->next();
var_dump($g->current()); # int(1)
$g->next();
var_dump($g->current()); # int(2)
$g->next();
var_dump($g->current()); # int(3)

foreach(mygenerator() as $i) {
    var_dump($i);
} # 順にint(0), int(1), int(2), int(3)