does python have useless destructors?

[Isaac To]

>>>>> "David" == David Turner <dkturner at telkomsa.net> writes:

    David> Also, I'd like to point out that destructor semantics and GC are
    David> not necessarily related.  There's no rule that says the
    David> destructor has to be called at the same time as the memory is
    David> freed.  In fact, there are several good reasons for separating
    David> the events.

    David> One could conceivably even use a pre-processor to implement
    David> Python deterministic destructor semantics in Python.  It's really
    David> just a case of the compiler inserting a number of implicit
    David> try/finally blocks, and reference counting.  I can't see any
    David> reason why it couldn't be done in Jython.

Unluckily, currently there is no concept of "local scoped objects" in
Python.  What it means is that a variable can be local, but an object
cannot.  An object in Python is always heap allocated, so there is no way to
know that whether an object has a reference staying outside the current
scope when the current scope exits---short of dictating how the garbage
collector works (i.e., it must count reference).  I think the primary
developer in Python has already completely rejected the very idea, probably
because it is impractical to implement in Jython.

Regards,
Isaac.