Alias for an attribute defined in a superclass

Fri Apr 1 05:54:06 EDT 2011

Raymond Hettinger wrote:
> On Mar 31, 3:14 pm, Ben Finney <ben+pyt... at benfinney.id.au> wrote:
>>> Howdy all,
>>>> I want to inherit from a class, and define aliases for many of its
>> attributes. How can I refer to “the attribute that will be available by
>> name ‘spam’ once this class is defined”?
>>>> class Foo(object):
>> def spam(self):
>> pass
>>>> def eggs(self):
>> pass
>>>> class Bar(Foo):
>> beans = Foo.spam
>> mash = Foo.eggs
>>>> Is that the right way to do it?
>>>> For methods, that will work just fine. For attributes, you will need
> to make @property accessors that get and set the underlying attribute.
>>> Raymond
>For attributes you could also override __getattribute__ & __setattr__ to 
wrap Bar's names into Foo's names.
Could work also for methods, but for methods your current idea is much 
more simple.
class Foo(object):
 def __init__(self):
 self.spam = 'someSpam'
 self.eggs = 'fewEggs'
 def vanilla(self):
 return self.spam
class Bar(Foo):
 _map = {
 'beans': 'spam',
 'mash': 'eggs',
 'chocolate': 'vanilla',
 }
 def __getattribute__(self, attribute):
 getSafely = object.__getattribute__
 _map = getSafely(self, '_map')
 if attribute in _map:
 return getSafely(self, _map[attribute])
 else:
 return getSafely(self, attribute)
Bar().chocolate()
'someSpam'
Bar().mash
'fewEggs'
JM