On 4 Dec 2006, at 3:13, Nick Coghlan wrote:
> Ben Wing wrote:
>> i don't like the current super() at all. having to type super(Foo,
>> self).__init__(...) is messy, hard to remember, and error-prone.
>
> Yup.
>
>> it
>> also introduces an unfortunate dependency in that the name of the
>> class
>> (Foo) has to be hard-coded in the call, and if you change the
>> class name
>> you also have to go and change all super() calls -- more chances for
>> errors. as a result, i imagine there's a strong urge to just
>> hardcode
>> the name of the parent -- a bad idea, and the reason why super() was
>> introduced in the first place.
>
> Also yup.
>
> The fact that these drawbacks are fairly obvious, yet nothing has
> been done
> about them should suggest something to you about the difficulty of
> actually
> solving this problem in a reliable fashion ;)
>
> The Python Cookbook has a few interesting approaches to making
> cooperative
> super calls easier to write, but they all tend to have some kind of
> drawback
> that makes them inappropriate for making part of the language core.
>
>> instead, `super' should work like in other languages. a couple of
>> ideas:
>>
>> -- super.meth(args) calls the superclass method `meth', in the
>> same way
>> that super(Foo, self).meth(args) currently works. (this is the same
>> syntax as in java. this probably requires making `super' be a
>> keyword,
>> although it might be possible to hack this by examining the
>> current call
>> stack.)
>
> It's the implementation that's the real sticking point here, so
> without code
> this idea isn't likely to go anywhere.
I was bitten by the urge to play with this today, and modified my
previous "self" hack to handle "super" also, so that the following
code works:
class D (C):
@method
def sum(n):
return super.sum(n * 2) - self.base
Posted as "evil2.py" here:
http://www.lag.net/robey/code/surf/
Because hacking "super" requires having the class object handy, this
one needs a metaclass to do its magic, which is a shame. I guess if
it was implemented inside the cpython compiler, it would be less of a
problem.
robey
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