"Andreas Huber" <ah2003@gmx.net> writes:
David Abrahams wrote:
I'm reading it like a bible only when it helps to argue my case ;-).
I know there's a smiley, but you're not doing your credibility any favors with that statement. It makes me wonder how many other decisions in the design have such a flimsy foundation.
I think a foundation for a decision is not flimsy when the behavior in question has proved to be useful in practice. So far nobody, who seems to have experience with non-trivial FSMs, has doubted that it is useful to terminate a state machine when it is destructed (my assumption A1).
I don't doubt that it's often useful. I also think it is surely sometimes highly undesirable. If you remove A1, the "useful" behavior is trivial to achieve without transforming the FSM, so it seems that a design without A1 is both more flexible and more orthogonal.
BTW, as pointed out by someone else the user *does* have a choice. If she happens to have an exit action that she'd rather not have executed upon destruction then she can always transform the machine part in question such that her action is executed as part of a transition action instead (I would consider it a design error not to do so).
Why?
Every Moore machine (an FSM that has only entry and exit actions) can be transformed to a Mealy machine (an FSM that has only transition actions) and vice versa.
Why require a transformation when it's not neccessary? -- Dave Abrahams Boost Consulting http://www.boost-consulting.com