If I'm not mistaken, you should change foo::offsetGet()
to this:
public function offsetGet($offset)
{
if (!$this->offsetExists($offset)) {
return new self($this->elementId);
} else {
return $this->data[$offset];
}
}
It returns an instance of itself if there's no element at the given offset.
That said, foo::__construct()
should be called from bar::__construct()
as well and be passed a value other than null
:
class bar extends foo
{
public $element = null;
public function __construct()
{
parent::__construct(42);
}
}
Update
To chain calls, you need to return the instance from __call()
:
public function __call($functionName, $arguments)
{
if ($this->elementId !== null) {
echo "Function $functionName called with arguments " . print_r($arguments, true);
}
return $this;
}