Re: [Sc-devel] RFC: Pbind redesign?

[Julian Rohrhuber <rohrhuber@xxxxxxxxxxxxxx>]

Hi Ron,

thinking a bit while implementing a simplification to cleanup 
(attached) I wondered whether it is such a good idea to move all the 
responsibility for cleaning up to an inner state of a consumer 
stream. This seems like calling for trouble later, as most people 
would not bother to implement it if they have a stream they want to 
end somehow. Also we don't want to create responsibility in places 
that don't relate directly to the cleanup.

we seem to have the trade off:

# Problem 1: calling more values from upstream than actually played

# Problem 2: having to check every single event for whether it 
contains things to be done. Difficult implementation.


What about this: any stream that needs to be released adds some hook 
to itself (or a cleanup event) to every _downstream_ event. Then all 
we have to call is some finish function in this event, and remove the 
hook. I think this would solve both problems.







// may not be needed:
//////////////////////////////////


EventCleanup {
	var functions;

	*new {
		^super.newCopyArgs(IdentitySet.new) // btw far more efficient!
	}

	add { arg event;
		event[\addToCleanup].do { | f | functions.add(f) };
		event[\removeFromCleanup].do { | f | functions.remove(f) };
	}

	cleanup { arg inevent, outevent;
		functions.do { | f | f.value(inevent) };
		outevent[\removeFromCleanup] = 
functions.union(outevent[\removeFromCleanup]);
		^outevent
	}

}


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