Tim Delaney wrote:
From: Calvin Spealman [EMAIL PROTECTED]
I believe the direction my PEP took with all this is a good bit
primitive compared to this approach, although I still find value in it
because at least a prototype came out of it that can be used to test
the waters, regardless of if a more direct-in-the-language approach
would be superior.
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.
And how does speed deteriorate for methods with no uses of super at all
(which will, I suspect, be in the majority)?
regards
Steve
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