Self Referencing Class Definition in python

Question

is there any way to reference a class name from within the class declaration? an example follows:

class Plan(SiloBase):     cost = DataField(int)     start = DataField(System.DateTime)     name = DataField(str)     items = DataCollection(int)     subPlan = ReferenceField(Plan) 

i've got a metaclass that reads this information and does some setup, and the base class implements some common saving stuff. i would love to be able to create recursive definitions like this, but so far in my experimentation i have been unable to get the effect i desire, usually running into a "Plan is not defined" error. I understand what is happening, the name of the class isn't in scope inside the class.

Answer 1

Try this:

class Plan(SiloBase):     cost = DataField(int)     start = DataField(System.DateTime)     name = DataField(str)     items = DataCollection(int)  Plan.subPlan = ReferenceField(Plan) 

OR use __new__ like this:

class Plan(SiloBase):      def __new__(cls, *args, **kwargs):         cls.cost = DataField(int)         cls.start = DataField(System.DateTime)         cls.name = DataField(str)         cls.items = DataCollection(int)         cls.subPlan = ReferenceField(cls)         return object.__new__(cls, *args, **kwargs)