threading support in python

[sjdevnull at yahoo.com]

Paul Rubin wrote:
> Jean-Paul Calderone <exarkun at divmod.com> writes:
> > >which more explicitly shows the semantics actually desired.  Not that
> > >"huge" a benefit as far as I can tell.  Lisp programmers have gotten
> > >along fine without it for 40+ years...
> >
> > Uh yea.  No lisp programmer has ever written a with-* function... ever.
>
> The context was Lisp programmers have gotten along fine without
> counting on the refcounting GC semantics that sjdevnull advocates
> Python stay with.  GC is supposed to make it look like every object
> stays around forever, and any finalizer that causes an explicit
> internal state change in an extant object (like closing a file or
> socket) is not in the GC spirit to begin with.

I disagree, strongly.  If you want "every object stays around forever"
semantics, you can just not free anything.  GC is actually supposed to
free things that are unreachable at least when memory becomes tight,
and nearly every useful garbage collected language allows destructors
that could have effects visible to the rest of the program.  Reference
counting allows more deterministic semantics that can eliminate
repeating scope information multiple times.