After playing with my overloads library and trying to apply it to FSM
I realized that some metaprogramming can be replaced with natural
overload resolution rules. After realizing it, I come to conclusion that
simple FSM can be implemented as a set of call operators and a list of
states. Each call operator represents a transition and follows this
pattern:
NewState operator()(State,Event) const;
Transition functions are generated in process_event function on first
call (in a constructor of static variable, for example). Each function
extracts current state from StatesAsVariant (boost::variant of all
states):
template<class StatesAsVariant, class State, class Event>
void transition(FSM& fsm, StatesAsVariant states, Event event)
{
states = fsm( get<State>(states), event); // select best transition
// according to overload
// resolution rules
}
The only metaprogramming algorithm is for_each<States> to initialize
transition table for the event.
Comments?
--
Alexander Nasonov
