include "primitives.alh"

SimpleAttribute Boolean {}
SimpleAttribute TriState {}
SimpleAttribute String{
    constraint = $
        String function constraint(model : Element, name : String):
            if (is_physical_string(model["model"][name])):
                return "OK"!
            else:
                return "String has non-string value"!
        $
}

Class State {
    isInitial : Boolean
    isError : Boolean
    name : String
}

Class Up : State {}
Class Down : State {}
Class Neutral : State {}

Association Transition (State, State) {
    objDetected : TriState
}
Association UpPressed : Transition (State, State) {}
Association NonePressed : Transition (State, State) {}
Association DownPressed : Transition (State, State) {}