使用递归迭代器遍历作为属性值的数组

我正在开发一个内容迭代器,它应该递归到数组中,并将每个值作为单独的迭代返回。这是我们班的一个精简版:

class ContentIterator extends \RecursiveIteratorIterator
{
    private $_ordinal = 0;

    public function __construct()
    {
        parent::__construct(new \RecursiveArrayIterator(\func_get_args()));
    }

    public function key()
    {
        return $this->_ordinal;
    }

    public function getChildren()
    {
        $current = $this->current();
        if (property_exists($current,'array')) return new \RecursiveArrayIterator(array_values($current->array()));
        throw new \Exception('Shouldn\'t reach here!');
    }

    public function hasChildren()
    {
        $current = $this->current();
        return \is_array($current) || $current instanceof \Traversable;
    }

    public function next()
    {
        parent::next();
        ++$this->_ordinal;
    }

    public function rewind()
    {
        parent::rewind();
        $this->_ordinal = 0;
    }

}

这是测试:

class TestSource {
  public $array = ['a','b','c'];
}

foreach (new ContentIterator(new TestSource) as $key => $value) 
    echo "$key => ".json_encode($value)."\n";

测试应产生以下结果:

0 => "a"
1 => "b"
2 => "c"

它实际上会产生这样的结果:

0 => ["a","b","c"]

如何修复ContentIterator以使其正确执行?

(是的,我知道我可以使用ArrayIterator或RecursiveArrayIterator在数组中递归。这不是重点。)