|Think about Loose Coupling|
Re^9: a State machine with Roles - possible? (class or instance)by salva (Abbot)
|on Jun 01, 2013 at 11:25 UTC||Need Help??|
Class::StateMachine::Declarative is the result of my experience developing complex state machines, but for my current kind of problems that may be quite specific, I don't know how that could bend to the problems of other people.
I am still not completely happy with it, but it is true that the current iteration is much better than its predecessors.
Is it possible to use Class::StateMachine in a Role
No, because Class::StateMachine is a metaclass, it plays with the method resolution order (mro) to attain the specific state machine method resolution.
When I designed Class::StateMachine I have a hard time figuring how support the state machine while retaining the full perl object oriented semantics (specifically inheritance and multiple inheritance). But then, when I got to use it for practical matters, I discover that inheritance and state machines do not mix well.
Thinks like defining some states in one class, and others in a subclass, or refining them in the subclass is not a great idea.
It is ok to reuse (via inheritance or roles) the code that implements simple actions, but the state machine definition should be a coherent entity.