Am I correct in thinking that `IteratorAggregate` only provides array-like *read* access to an object? If I need to write to the object-as-array, then I need to use `Iterator`?

Demonstration of an IteratorAggregate object causing a fatal error when trying to add a new element follows:

```
<?

class foo implements IteratorAggregate {

    public $_array = array('foo'=>'bar', 'baz'=>'quux');

    public function getIterator() {
        return new ArrayIterator($this->_array);
    }

} // end class declaration

$objFoo = & new foo();

foreach ( $objFoo as $key => $value ) {
        echo "key: $key, value: $value\n";
}

$objFoo['reeb'] = "roob";

foreach ( $objFoo as $key => $value ) {
        echo "key: $key, value: $value\n";
}

```

---

```
$ php test.php
key: foo, value: bar
key: baz, value: quux

Fatal error: Cannot use object of type foo as array in /var/www/test.php on line 20

Call Stack:
    0.0009      57956   1. {main}() /var/www/test.php:0

```