On 4/30/07, Tim Delaney <tcdelaney@optusnet.com.au> wrote:
I've been working on improved super syntax for quite a while now - my original approach was 'self.super' which used _getframe() and mro crawling too. I hit on using bytecode hacking to instantiate a super object at the start of the method to gain performance, which required storing the class in co_consts, etc. It turns out that using a metaclass then makes this a lot cleaner.
However, I seem to think that if the __this_class__ PEP goes through, your version can be simplified as well. No tricky stuffy things in cells would be needed, but we can just expand the super 'keyword' to __super__(__this_class__, self), which has been suggested at least once. It seems this would be much simpler to implement, and it also brings up a second point.
Also, I like that the super object is created at the beginning of the function, which my proposal couldn't even do. It is more efficient if you have multiple super calls, and gets around a problem I completely missed: what happens if the instance name were rebound before the implicit lookup of the instance object at the time of the super call?
You could expand it inline, but I think your second point is a strong argument against it. Also, sticking the super instance into a cell means that inner classes get access to it for free. Otherwise each inner class would *also* need to instantiate a super instance, and __this_class__ (or whatever it's called) would need to be in a cell for them to get access to it instead.
BTW, one of my test cases involves multiple super calls in the same method - there is a *very* large performance improvement by instantiating it once.
Note that I would now advocate the creation of the super object at the beginning of function, and when I talk about expanding super to super(__this_class__, self) I do mean doing it at the beginning of the function, just like you are saying, so we're in agreement here. -- Read my blog! I depend on your acceptance of my opinion! I am interesting! http://ironfroggy-code.blogspot.com/