I have gone through your book on Statecharts and found it a quite novel approach to model hierarchical state machines. I would like to clear some of the doubts that I had, hope you would find some time to answer them -
1. Is it mandatory that a Composite state has to transition to a sub-state as per HSM through the Q_INIT signal ? Alternatetly, could we have a design in which it is possible to remain in a composite state and transistion to sub-states explicitly in response to events ? Would the QF support this type of behaviour ?
2. This is more on design - so I would like to know more form your experience - what would be the criteria / guidelines for getting a good HSM design (proper hierarchy, composite states, orthogonal states).