Hi, Whenever I had to develop an FSM in the past, I chose either of the following paths: - For small and simple machines I often resorted to the IMHO ugly nested switch-case approach. - For bigger and more complex machines, I often used a code-generation approach because I failed to find a satisfactory library.
No matter what solution I chose, I have always been missing code-expressiveness, ease-of-use and good maintainability. An attempt at an easy-to-use FSM library that supports well-maintainable and code-expressive machines of almost any size and does not require a code generator can be found in the fsm directories in the boost-sandbox and here: http://groups.yahoo.com/group/boost/files/FSM/ There is comprehensive tutorial and rationale documentation. All code has been tested with MSVC7.1 and boost 1.30.0 Features include: - Straightforward transformation from UML state chart to executable C++ code and vice versa - Comprehensive UML semantics support: - Hierarchical (composite, nested) states - Orthogonal (concurrent) states - Entry-, exit- and transition-actions - Guards - Event deferral - Error handling support - Full type-safety - State-local storage - Customizable resource management Any feedback is most welcome. Thanks, Andreas P.S. For people who are not yet using the boost library and would like to run the examples, FSM.zip contains a 4-step quick start guide. P.P.S. Developer summary ;-), copy-paste into your code editor: //////////////////////////////////////////////////////////////////////////// // The following code implements the state-machine: // -------------------------------- // | | // | O Active | // | | |<---- // | v | | EvReset // | ---------------------------- | | // | | | |----- // | | Stopped | | // | ---------------------------- | // | | ^ | // | | EvStartStop | EvStartStop |<-----O // | v | | // | ---------------------------- | // | | | | // | | Running | | // | ---------------------------- | // -------------------------------- #include <boost/fsm/event.hpp> #include <boost/fsm/state_machine.hpp> #include <boost/fsm/simple_state.hpp> #include <boost/fsm/transition.hpp> namespace fsm = boost::fsm; class EvStartStop : public fsm::event< EvStartStop > {}; class EvReset : public fsm::event< EvReset > {}; struct Active; struct StopWatch : public fsm::state_machine< StopWatch, Active > {}; struct Stopped; struct Active : public fsm::simple_state< Active, StopWatch, fsm::transition< EvReset, Active >, Stopped > {}; struct Running : public fsm::simple_state< Running, Active, fsm::transition< EvStartStop, Stopped > > {}; struct Stopped : public fsm::simple_state< Stopped, Active, fsm::transition< EvStartStop, Running > > {}; int main( int argc, char * argv[] ) { StopWatch myWatch; myWatch.initiate(); myWatch.process_event( EvStartStop() ); myWatch.process_event( EvStartStop() ); myWatch.process_event( EvStartStop() ); myWatch.process_event( EvReset() ); return 0; } _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost
