Circular refs

[Adrian Eyre]

>> I can dream up a million ways to kludge around this bug, but I
>> was referring to a 'fix' to the Python source code. How hard can
>> it be?

> It's unclear, but I can give you a lower bound:  in all the years
> people have been whining about how easy this is to "fix", nobody
> has managed to fix it.

How about this:

import types

class Noisy:
    def __init__(self, name):
        self.name = name
        print "Created " + self.name
    def __del__(self):
        print "Destroyed " + self.name

# Only handles class instances (for now)
def mydel(obj, done = None):
    if done is None:
        done = []
    items = obj.__dict__.items()
    for key, value in items:
        if value in done:
            continue
        if type(value) != types.InstanceType:
            continue
        done.append(value)
        mydel(value, done[:])
        del obj.__dict__[key]

def main():
    a = Noisy("a")
    b = Noisy("b")
    a.b = b
    b.a = a
    mydel(a)
    del a
    mydel(b)
    del b
    print "End"

if __name__ == "__main__":
    main()

If I can fix this in Python (admittedly for a limited set of
cases, but it should be easy enough to expand on), then why
not in C?

--------------------------------------------
Adrian Eyre <mailto:a.eyre at optichrome.com>
Optichrome Computer Solutions Ltd
Maybury Road, Woking, Surrey, GU21 5HX, UK
Tel: +44 1483 740 233  Fax: +44 1483 760 644
http://www.optichrome.com 
--------------------------------------------