Python metaclass reminder

metaclass_reminder.py

class MetaClass(type):
	counter = 1

	def __new__(meta, name, bases, dct):
                """ Gets called when we read in the class definition for which this is the metaclass of"""
		print "MetaClass.__new__(%s, %s, %s, %s)" % (meta, name, bases, dct)
		dct['class_num'] = meta.counter
		meta.counter += 1
		return super(MetaClass, meta).__new__(meta, name, bases, dct)

	def __init__(cls, name, bases, dct):
                """ Gets called when we read in the class definition for which this is the metaclass of and after __new__
                    of the metaclass."""
		print "MetaClass.__init__(%s, %s, %s, %s)" % (cls, name, bases, dct)
		return super(MetaClass, cls).__init__(name, bases, dct)

	def __call__(cls, *args, **kwargs):
                """ Called when an object is created from the class of which this is a metaclass of.  args,kwargs are the normal 
                    init params"""
		print "MetaClass.__call__(%s, %s, %s)" % (cls, args, kwargs)
		return type.__call__(cls, *args, **kwargs)
		

class NormalClass(object):
	__metaclass__ = MetaClass

	def __new__(cls, *args, **kwargs):
                """ Called when class is instantiated and after the metaclasses __call__ method. """
		print "NormalClass.__new__(%s, %s, %s)" % (cls, args, kwargs)
		return super(NormalClass, cls).__new__(cls, *args, **kwargs)

	def __init__(self, *args, **kwargs):
                """ Called after meta.__call__ and normal.__new__  on the class returned by __new__"""
		print self.class_num
		print "NormalClass.__init__(%s, %s, %s)" % (self, args, kwargs)

class OtherNormalClass(object):
	__metaclass__ = MetaClass

	def __new__(cls, *args, **kwargs):
		print "OtherNormalClass.__new__(%s, %s, %s)" % (cls, args, kwargs)
		return super(OtherNormalClass, cls).__new__(cls, *args, **kwargs)

	def __init__(self, *args, **kwargs):
		print self.class_num
		print "OtherNormalClass.__init__(%s, %s, %s)" % (self, args, kwargs)	


if __name__ == "__main__":
	norm1 = NormalClass(5, a=2)
	norm2 = NormalClass(6, a=3)
	other1 = OtherNormalClass(7, a=12)

"""
Call orders with first params in brackets.

Call order on reading the class definition:
meta.__new__(meta), meta.__init__(class)

Call order on the class instantiation:
meta.__call__(class), class.__new__(class), class.__init__(self)

Call order when we call an instance:
class.__call__(self)
"""

"""TODO:
- Look up what the various methods should return and how does that effect the whole procedure.
- Maybe a full call graph to make this a bit cleaner.
"""