+ SCM handle = scm_hashq_create_handle_x (listeners_, ev_class, SCM_EOL);
+ SCM list = scm_cdr (handle);
+ // if ev_class is not yet listened to, we go through our list of
+ // source dispatchers and register ourselves there with the priority
+ // we have reserved for this dispatcher. The priority system
+ // usually distributes events in the order events are registered.
+ // The reuse of a previous priority when registering another event
+ // for a dispatcher/dispatcher connection bypasses the normal
+ // ordering, but it is the mechanism by which duplicate broadcasts
+ // of the same event from one dispatcher to another are avoided.