[Help-smalltalk] Re: Delay in a Process and sending #terminate

[Paolo Bonzini]

On 12/20/2010 11:06 AM, Holger Hans Peter Freyther wrote:
> On 12/18/2010 08:00 PM, Paolo Bonzini wrote:
>
> > Aha, I could now reproduce what you meant, but it's not a bug.  The problem is
> > that if you're already in the #ensure: block, or in the #critical: block,
> > #terminate will be able to unwind it.  So, #ensure: is fundamentally
> > incompatible with #terminate (at least as it is implemented now).  I have to
> > think more about it.
>
> I assume it is the same for sending any message? I have moved from terminate
> to send a simple Notification/Exception. But as it is mostly implemented the
> same way, I face the same issue?

I think ProcessBeingTerminated is different, but it has the problem that 
it is more akin to #ifCurtailed: than to #ensure:.

It would be interesting to see what other dialects do.  But it is better 
to think of #terminate as a very bad idea in general :) and rethink 
processes to implement *interruption* rather than termination.

Another possibility in your case is to implement the processes 
collection using a wrapper, so that iteration will filter out processes 
that have terminated.

I'm also thinking of moving #queueInterrupt: to a primitive or something 
like that so that it's not preemptable/interruptible.  This means that 
instead of removing itself from the collection, a terminating process 
could *atomically* ask another process to do the removal.

Paolo