How can I get a list of object vars?

Hi list. I'm trying to write a ORM in PHP. I want the ORM to have metadata mapping, which have a list of properties name and the value, without using any external file. (I like simple one, not want messy XML) I'm thinking PHP's reflective functions might help me to do that and treid get_object_vars but it doesn't return properties name and even value itself when it haven't been assigned any value. Is there any good way to get a list of properties name and the value? Or some good PHP framework's implementation to study for this? Thanks in advance.