Re: using finalizers

[Tomas Hlavaty]

On Sat 01 Jan 2022 at 12:00, Stefan Monnier <monnier@iro.umontreal.ca> wrote:
>> One more question: Because make-finalizer in Emacs Lisp does not take
>> the object into account,
>
> Not sure what you mean by "the object" here.

In Common Lisp, the usual semantics is: call this thunk when this object
gets collected.  I pass the object and thunk and make-finalizer does the
rest.

In Emacs Lisp, the semantics is: call this thunk when the returned
finalizer gets collected.  So, if I want to finalize my object, I have
too keep the reference to the finalizer.

>> I have to make sure to hold the reference to the finalizer somehow.
>> However, this might not be trivial, because a smart compiler could
>> eliminate the reference.
>
> And I definitely don't know what you mean by "the reference", so I have
> no idea why a smart compiler would be able to eliminate it.

In Emacs Lisp, my object itself needs to keep the finalizer around,
otherwise it would get finalized.