More than likely you are seeing the effects of using the __call magic method. Lots of the Magento classes use it by extending Varien_Object. If you track the parent classes of the class you are using, you will find that ultimately, the top level class is Varien_Object. The parent class will allow you to store ANYTHING on a class.
For example:
$o = new Varien_Object(); $o->setSuperCoolVariable(42); //Edit: Apparently I didn't get enough coffee this morning! $lifeUniverseEverything = $o->getSuperCoolVariable();
if( $lifeUniverseEverthing === 42) { echo("What's the question???"); }
if( $lifeUniverseEverthing === 42 ) { echo("What's the question???"); }
All the variations are the same. Just watch out for child classes that implement a method that is named the same as one of your underlying variables.
In that case you could always use this:
$o->getData('super_cool_variable');
Funny thing is, they only need to add a few wrapper methods and they could implement ArrayAccess on Varien_Object. then you could even use array access syntax.
