UML14 — Change events issue

Summary: Change events should be generalizable. For example, a traffic light
changing to any color is a more general event than a change of that
traffic light to Red only. If the second event happens, then the
first must have happened also. A state machine with a trigger event
on the first event will transition if the second event occurs.

The semantics document says that an event can trigger transitions which
have a more general event [p 113, UML 1.1 Semantics].

Comments:

This is close to issue # 29, "Events should be generalizable
elements", which Rumbaugh filed and withdrew. His reasoning is that
signals are generalizable and event are just pointers to them, so it
is not necessary for events to be generalizable. In fact, events are
more than pointers to signals, as shown in the event meta-model
[figure 18, page 98, of UML 1.1 Semantics]. Events also cover call
events, time events, and change events.

Considered and declined.