[Python-3000] PEP: Eliminate __del__

Michael Bayer mike_mp at zzzcomputing.com
Fri May 4 18:45:07 CEST 2007

On May 4, 2007, at 10:33 AM, Giovanni Bajo wrote:

> On 5/4/2007 4:21 PM, Michael Bayer wrote:
>> why not encapsulate the "proper" weakref-based approach in an easy- 
>> to-use method such as "__close__()" ?  that way nobody has to  
>> guess how to follow this pattern.
> Because the idea is that the callback of the weakref will *NOT*  
> hold a reference to the object being destroyed, but only to the  
> resources that need to be deallocated (that is, to the objects  
> bound as attributes of the object).

a __close__() method on a class is first bound to the class, not any  
particular self.  the Python runtime could detect this and create the  
appropriate callable/weakref scenario behind the scenes; not even  
binding __close__() to the self in the usual way.  obviously it cant  
be a pure python solution, it would have to be a specific runtime  
supported idea (the same way __metaclass__ or any other magic  
attribute is supported).

i just dont understand why such an important feature would have to be  
relegated to just a "recipe".  i think thats a product of the notion  
that "implicit finalizers are bad, use try/finally".  thats not  
really valid for things like buffers that flush and database/network  
connections that must be released when they fall out of scope.

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