Aahz wrote:
> On Tue, Apr 18, 2006, Thomas Wouters wrote:
>
>> - Compiler hackery involving a magical variable name, say '__class__'
>>or '__CLASS__'. The compiler would treat this specially, probably
>>stored in the class dict, and type() (which is, after all, called to
>>actually create the class) would stuff the actual class object in
>>there. It causes a reference cycle, but all newstyle classes already
>>do that ;P The main issue is that __CLASS__ would be new magic. It
>>wouldn't exist when the class body is executed, and it would be a
>>special form of enclosed variable afterwards (it should be extracted
>>from the class namespace, using a similar mechanism as closures.)
>
>
> It's not clear to me that this requires compiler hackery, just metaclass
> hackery. Am I missing something?
>
> Also, my idea is that self.super is a bound method/closure that already
> contains a reference to the class. This makes dynamic classes more
> difficult in some ways, but anyone who wants to play those sorts of games
> should expect to do some magic mangling. If it's reasonably
> well-documented, it wouldn't even be that difficult.
Well:
class A(object):
def whoami(self):
return 'A'
def dostuff(self):
print 'I (%s) am doing A stuff...' % (self.whoami())
class B(A):
def whoami(self):
return 'B-ish %s' % (self.super.whoami())
def dostuff(self):
print 'Some B stuff...'
self.super.dostuff()
class C(B):
def whoami(self):
return 'C'
def dostuff(self):
print 'Some C stuff...'
self.super.dostuff()
Reading this statically, I think it's clear how this should work. So,
when C().dostuff() is called, we want to see:
Some C stuff...
Some B stuff...
I (C) am doing A stuff...
When B().dostuff() is called, we want to see:
Some B stuff...
I (B-ish A) am doing A stuff...
But how can we do that without the function being bound to a class?
self.whoami() in A.dostuff needs to access the 'real' self. self.super
in B.dostuff should be super(B, self), even when self.__class__ is C.
Because Python *isn't* reading the functions statically to determine
class and method layout, actually making this work seems very hard.
--
Ian Bicking / [EMAIL PROTECTED] / http://blog.ianbicking.org
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