metaClasses.py

#   Uses for metaclasses
#
#   Register a class on definition
#   Initialise attributes (Usually to set a name)
#   Modify a class based on its definition
#   Ensure subclasses implemention
#   Totally mess with the way a class behaves


# class Car:
#     def __init__(self, color):
#         self.color = color

#     def drive(self):
#         print("You are driving the car")


def init_func(self, color):
    self._color = color


def drive(self):
    print("You are driving the car")


Car = type("Car", (object,), {"__init__": init_func, "drive": drive})

my_car = Car("red")
my_car.drive()


# A metaClass is a callable which returns a class


# A function as a metaclass
# def stupid_metaclass(classname, bases, attrdict):
#     return type(classname, bases, attrdict)


# class MyClass(metaclass=stupid_metaclass):
#     pass


class MyMeta(type):
    pass


class MyClass(metaclass=MyMeta):
    pass


instance = MyClass()
# >>> type(instance)
# <class '__main__.MyClass'>
# >>> type(MyClass)
# <class '__main__.MyMeta'>
# >>>