I believe you misunderstand me. My point was that you can use Self to access the public variables of a type which are otherwise inaccessible if you have a local variable of a method with the same name.
It aids clarity of assignment as it prevents you having to declare parameter names such as fuel_new or xp in bradford6's example holding the new value for xpos where using xpos as the parameter and accessing the public variable xpos by using Self.xpos would suffice.
It aids clarity of assignment as it prevents you having to declare parameter names such as fuel_new or xp in bradford6's example holding the new value for xpos where using xpos as the parameter and accessing the public variable xpos by using Self.xpos would suffice.