Python-сообщество

class A(object):

	@property
	def x(self):
		return 1


class B(A):

	@property
	def x(self):
		return super(B, self).x * 2


>>>b= B()
>>>b.x
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 4, in t
TypeError: must be type, not classobj

class B(A):

	@propety
	def x(self):
		return A.x.fget(self) * 2

class A_(object):
    
    def _get_x(self):
        return 1
    
    x = property(fget= _get_x)
    
    
class B_(A_):
    
    def _get_x(self):
        return super(B_, self)._get_x(self) * 2
        
    x = property(fget= _get_x) 

class PropertyMeta(type):

    def __new__(cls, name, bases, dct):
        property_dict = dict()
        for k,v in dct.items():
            if isinstance(v, property):
                property_dict[k] = v
        for base in bases:
            for k, v  in base.__dict__.items():
                if property_dict.get(k) and isinstance(v, property):
                    if v.fget:
                        dct['_get_%s' % k] = v.fget
                    if v.fset:
                        dct['_set_%s' % k] = v.set
                    if v.fdel:
                        dct['_del_%s' % k] = v.fdel
        return type.__new__(cls, name, bases, dct)
        
class A(object):
    
    @property
    def x(self):
        return 1
        

class B(A):
    __metaclass__ = PropertyMeta
    
    @property
    def x(self):
        return self._get_x() * 2

class PropertyMeta(type):
    def __new__(cls, name, bases, dct):
        property_dict = dict()
        for k,v in dct.items():
            if isinstance(v, property):
                property_dict[k] = v
        for base in bases:
            for k, v  in base.__dict__.items():
                if property_dict.get(k) and isinstance(v, property):
                    p = property_dict.get(k)
                    for f_type in ['fget', 'fset', 'fdel']:
                        if getattr(v, f_type):
                            dct['_%s_%s' % (f_type[1:], k)] = getattr(v, f_type)
                            if not getattr(p, f_type):
                                dct[k] = cls._set_property_func(dct[k], f_type, getattr(v, f_type))
        
        return type.__new__(cls, name, bases, dct)

    @classmethod
    def _set_property_func(cls, obj, key, func):
        # через setattr вылитает ошибка, что обьекты из dct только для чтения
        fget = obj.fget
        fset = obj.fset
        fdel = obj.fdel
        if key == 'fget': fget = func
        elif key == 'fset': fset = func
        else: fdel == func 
        return property(fget= fget, fset= fset, fdel= fdel)

class A(object):
    @property
    def x(self):
        return 1
        
    @x.setter
    def x(self, value):
        print 'set x = %s' % value
        
class B(A):
    __metaclass__ = PropertyMeta
    @property
    def x(self):
        return self._get_x() * 2        
        

    @x.deleter
    def x(self):
        print 'del x'
    
>>> b=B()
>>> b.x
2 
>>> b.x=10
set x = 10
>>> del b.x
del x