__del__ not working with cyclic reference?

[Peter Abel]

janeaustine50 at hotmail.com (Jane Austine) wrote in message news:<ba1e306f.0307011837.269e3d2a at posting.google.com>...
> I have some code using singleton pattern. The singleton instance
> is shared as a class variable. The problem is that the singleton
> instance is not cleared automatically.
> 
> Following is a simplified version that shows the problem:
> 
> --------
> #foobar.py
> class FooBar:
>     def __del__(self):
>         print "FooBar removed"
> 
> FooBar.foobar=FooBar()
Doen't understand what you're doing here.
For me you define a classvariable named **foobar**
which is bound to an instance of class **FooBar**.
> --------
> 
> c:\python23>python foobar.py
> 
> c:\python23>
> 
> It doesn't print anything.
> 
> Why is this so? Due to the cyclic reference? Isn't python's gc
> supposed to treat it? What singleton idiom is recommended 
> otherwise?
> 
For me the following works:
>>> class FooBar:
... 	def __del__(self):
... 		print "FooBar removed"
... 		
>>> foo=FooBar()
>>> del foo
FooBar removed
>>> 
> Thanks
> 
> Jane

Regards
Peter