Turn iterable into iterator

问题

In PHP 7.1 a new iterable pseudo-type was introduced.

Is there a straightforward way to transform a generic iterable into an Iterator? Or should I use something like

if (is_array($iterable)) {
    return new \ArrayIterator($iterable);
}

return new \IteratorIterator($iterable);

来源：https://stackoverflow.com/questions/43474857/turn-iterable-into-iterator