Object attr

memoized_slots.py

class MemoizedSlots(object):
    def _fallback_getattr(self, key):
        raise AttributeError(key)
        
    def __getattr__(self, key):
        if key.startswith('_memoized'):
            raise AttributeError(key)
        elif hasattr(self, '_memoized_attr_%s' % key):
            value = getattr(self, '_memoized_attr_%s' % key)()
            setattr(self, key, value)
            return value
        elif hasattr(self, '_memoized_method_%s' % key):
            fn = getattr(self, '_memoized_method_%s' % key)
            
            def onshot(*args, **kwargs):
                result = fn(*args, *kwargs)
                memo = lambda *args, **kwargs: result
                memo.__doc__ = fn.__doc__
                memo.__name__ = fn.__name__
                setattr(self, key, memo)
                return result
            onshot.__doc__ = fn.__doc__
            return onshot
        else:
            self._fallback_getattr(key)
                
            m = lambad *args, **kwargs: return 
            

memorized_solts.py

Q:getattr, getattr 的作用?
A:

1. getattr(self, 'foo') == self.foo
2. ｀__getattr__｀ 的调用情况: instance 先在自己的属性中找如果找到则不调用, 但是如果没找到,则会调用 ｀__getattr__｀. 因此 ｀__getattr__ ｀是找`type(instance)｀的属性. 根据　getattr()　 的说明,如果调用不好,就会出现递归情况出现
3. 深入: getattribute 是无条件调用,则instance的任何属性都会调用他 ,只有在此调用　raise AttributeError 时才会调用__getattr__
   4.setattr/ setattr: setattr(self, 'foo', 1) == self.foo=1, setattr　会在instance attribute dict 添加，　如果在__setattr__ 中做self.name='foo'，　将会出现递归