Re: finalisation

[skaller <skaller@maxtal.com.au>]

Damien Doligez wrote:
> 
> >From: skaller <skaller@maxtal.com.au>

> If python specifies reference counting, I guess the only solution is
> to implement reference counting.  

	Python specifically _doesn't_ specify reference counting,
it specifies garbage collection. But the current implementation
is deficient in that it uses reference counting. So I need to
be compatible with existing programs at least as far as preserving
their correctness provided only that doesn't depend on synchronous
finalisation (a delay is OK, a change of order may not be).

>You can use O'Caml's finalisers to
> help you in the following way:
> 
> Add a reference count field to each finalisable object.  Initialise it
> to 1 upon allocation and register a finalisation function for this
> object.  Increment the reference count when you create a new reference
> from another finalised object, and decrement it when you remove a
> reference (you can do it by simply calling its finalisation function).

	I'm not sure how this works .. a reference from a finalised
object to another can be indirect (via another object). I'd like to
avoid
the cost of maintaining reference counts for non-finalisable objects.


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John (Max) Skaller, mailto:skaller@maxtal.com.au
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