"Inherit methods, run validations" traceMe = False def trace(*args): if traceMe: print('[' + ' '.join(map(str, args)) + ']') class BuiltinsMixin: def __add__(self, other): return self.__getattr__('__add__')(other) # Route to validator def __str__(self): # Finish operations return self.__getattr__('__str__')() def __getitem__(self, index): return self.__getattr__('__getitem__')(index) def __call__(self, *args, **kargs): return self.__getattr__('__call__')(*args, **kargs) # Plus any others needed def accessControl(failIf): def onDecorator(aClass): class onInstance(BuiltinsMixin): # Inherit methods def __init__(self, *args, **kargs): self.__wrapped = aClass(*args, **kargs) def __getattr__(self, attr): trace('get:', attr) if failIf(attr): raise TypeError('private attribute fetch, ' + attr) else: return getattr(self.__wrapped, attr) def __setattr__(self, attr, value): trace('set:', attr, value) if attr == '_onInstance__wrapped': self.__dict__[attr] = value elif failIf(attr): raise TypeError('private attribute change, ' + attr) else: setattr(self.__wrapped, attr, value) return onInstance return onDecorator def Private(*attributes): return accessControl(failIf=(lambda attr: attr in attributes)) def Public(*attributes): return accessControl(failIf=(lambda attr: attr not in attributes))