On Fri, 01 Apr 2011 09:14:03 +1100, Ben Finney wrote: > Howdy all, > > I want to inherit from a class, and define aliases for many of its > attributes.
Are these aliases of arbitrary aliases, or only of methods, as in your example below? > How can I refer to “the attribute that will be available by > name ‘spam’ once this class is defined”? You might be able to use the descriptor protocol to do something like that, but otherwise I don't think you can. However, I note that your example isn't *quite* how you describe it above. > class Foo(object): > def spam(self): > pass > def eggs(self): > pass > > class Bar(Foo): > beans = Foo.spam > mash = Foo.eggs This assigns the name Bar.beans to the method object Foo.spam. If you now rebind the name Foo.spam to something else, Bar.beans will not likewise change, but will continue to refer to the original. This is contrary to your earlier description, where Bar.beans should also change. This is no different from the usual Python namespace behaviour: x = 42 y = x y is an alias to x, until you rebind x. For variables, you can't change the behaviour; for attributes of a class, you may be able to write a descriptor to do something along those lines. > Is that the right way to do it? Will that leave me open to “unbound > method” or “is not an instance of ‘Bar’” or other problems when using > ‘Bar.beans’? I don't believe so. So long as you don't rebind the "alias" or the original, you should be fine. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
