"Alexander Nasonov" wrote:
However, FSMs are quite often used to describe class behavior but most of the time those classes are implemented without any fsm library. People just look at the diagram, then define a couple of bool members or 'int m_state;' and then they check restrictions imposed by fsm in every function drawn on the diagram (events are usually function calls).
Typical example of such class is POAManager (CORBA). It has active, holding, discarding, inactive, start and end states and there are create_POA, activate, discard_requests, hold_requests, deactivate and destroy functions.
I'd be happy to see a library in boost that can elegantly solve problems of such classes. Common problems are
1. Class invariants depend on state. This usually means that they lose simplicity and effectiveness. 2. Some class members are valid only in certain states. (Andreas has proved that state local storage is useful thing) 3. Because of 1 and 2, it's harder to maintan even basic exception safety.
Regardless of current review: do you have something in mind? How would API of such FSM look like? /Pavel