On Mon, Aug 16, 2004 at 09:49:00AM -0500, Jason Sibre wrote:
> __del__() method.)  I guess the appropriate use of __del__(), then, is to use
> it for clearing out in-memory resources that can be safely forgotten about in
> the case of an interpretter shutdown.  All resources that exist (or have
> components which exist) outside of the interpretter should be handled
> explicitly, ideally in a finally block, or the like.

I believe, perhaps mistakenly, that __del__ was orignally intended only
to help garbage collection out by breaking up cycles - this back in the
day when Python's GC was nothing but the core reference-counting
facility.  So the problem is that it sounds as though it's very like,
say, C++ destructors, which folks have learned to exploit in order to
work around more egregious shortcomings of that language, such as its
lack of garbage collection.

Which is ironic, because it was Stroustrup himself who, in a long-ago
article in comp.lang.c++, explained the essential problem with
finalizers in a GC'd setting.  In essence, GC is a way of simulating a
larger than available memory (1) - in the limit, simulating an infinite
space.  Now, if one actually had an effectively infinite space, how
would GC work in that environment?  It would do nothing, of course,
since the memory space already appears infinite, and doing any work to
reclaim dead space would serve no purpose.  So in the limit finalizers
should never be called by the GC system...

Except I'm sure the original statement was more compelling.  But as far
as I can tell, this predates Google's archives (or perhaps falls into a
gap), and whatever copies I once had seem to be gone, leaving only my
ever more fallible memory.  :-/


(1) in a virtual memory environment this is not untrue, but nitpickers
might prefer to think of it as making more efficent use of the
available [virtual] memory space - the same conclusion follow.

--
One lesson I've learned from my years as Linux's hood ornament is that
there's something worse: some folks can't be content to just take things
too seriously on their own.  They're not happy unless they can convince
others to go along with their obsession.  -- Linus