garbage collection / reference cycles (cont.)

[Aaron Brady]

Hello,

I am posting the code I mentioned on Saturday that collects garbage
and cyclic garbage in a flattened two-step process. The code takes
122 lines incl. comments, with 100 in tests. It should be in a reply
to this.

My aim is a buffer-like object which can contain reference-counted
objects. This is a preliminary Python version of the cycle detector.
I expect to port it to C++, but the buffer object as well as object
proxies are Python objects. The memory management strategy,
synchronization, etc., are other modules. It is similar in principle
to Python's own 'gc'. If it's sound, it may have some educational and
explanatory value also.

Anyway, since I received a little interest in it, I wanted to follow
up. It is free to play with. If there's a better group to ask about
this, or there are more scholarly, widely-used, or thorough treatments
or implementations, I'm interested.

 

[Aaron Brady]

Hello,

I am posting the code I mentioned on Saturday that collects garbage
and cyclic garbage in a flattened two-step process.  The code takes
122 lines incl. comments, with 100 in tests.  It should be in a reply
to this.

My aim is a buffer-like object which can contain reference-counted
objects.  This is a preliminary Python version of the cycle detector.

snip formality

Someone suggested that it wasn't clear to them what my goal was in
this post. I created a garbage collector that has an extra method
that user-defined objects don't have in Python's. It is 'final_attr',
which requests the objects to drop their reference to the specified
attr. After it returns, the object is moved to the back of the
collection queue. This means that it knows what references of its own
it is losing; they are still valid at the time 'final_attr' is called;
and other objects' references to /it/ are still valid too.

I want a technical discussion of its strengths and weaknesses.

Aahz suggested to try python-ideas:
http://mail.python.org/pipermail/python-ideas/2009-March/003774.html