Starting with 3.0.5, PHPDS_dependant offers a little new trick: read-only fields.

The problem is, when in a class you have a field which should be readable but not writable, you are often lead to make it protected and write an accessor. The resulting code is, well, not really smart:

class service extends PHPDS_dependant
{
	protected $quality = 'great';

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

From now on, just add the field, it will be read-only by default.

class service extends PHPDS_dependant
{
	protected $quality = 'great';
}
$o = $this->factory('service');
print $o->quality; // prints "great"
$o->quality = "bad"; // ERROR!!!

Of course you can still have an accessor, and it will be called automatically:

class service extends PHPDS_dependant
{
	protected $quality = 'great';

	public function quality()
	{
		return $this->quality.'!!';
	}
}
$o = $this->factory('service');
print $o->quality; // prints "great!!"

You can also have a read/write accessor:

class service extends PHPDS_dependant
{
	protected $quality = 'great';

	public function quality($value = null)
	{
		if (!is_null($value)) {
			$this->quality = $value;
		}
		return $this->quality.'!!';
	}
}
$o = $this->factory('service');
$o->quality = 'marvelous';
print $o->quality; // prints "marvelous!!"

In fact you can even have an accessor for a non-existent field...

A last note: as a side effect it prevent you from affecting a value to a non-declared field (unless the accessor catches it).