[Sc-devel] commit: new pattern termination scheme for event streams

[ronald kuivila <rkuivila@xxxxxxxxxxxx>]

Hi all,

I have committed a new early termination scheme for Patterns.  This  
gets rid of nil event as a termination message.
To make things work without having to call a stream when it  
terminates,  Streams that require cleanup now must create
a self-contained cleanup function.

This function is added to the array in ~addToCleanup in its first event.

"Terminators" (i.e. streams created by Pfin, Pfindur, Psync, and  
EventStreamPlayer) maintain a set of such cleanup functions found in  
its events.
When a terminator or stream requiring cleanup ends, it executes those  
cleanup functions, and then adds them to  ~removeFromCleanup and
propagates them up the tree.

Terminators remove any functions found in ~removeFromCleanup from  
their sets of cleanup funcitons.

RJK