module main {
    // State definitions
    type state_t = enum { S0, S1 };
    var BCR_state : state_t;
    var BP_state : state_t;
    var Printer_state : state_t;

    // Initial states
    init {
        BCR_state = S0;
        BP_state = S0;
        Printer_state = S0;
    }

    // Transitions for BCR
    next(BCR_state) :=
        case
            BCR_state == S0 : S1; // Barcode scanned
            BCR_state == S1 && BP_state == S0 : S0; // Data sent to BP
            default : BCR_state;
        esac;

    // Transitions for BP
    next(BP_state) :=
        case
            BP_state == S0 && BCR_state == S1 : S1; // Data received from BCR
            BP_state == S1 && Printer_state == S0 : S0; // Print command sent to Printer
            default : BP_state;
        esac;

    // Transitions for Printer
    next(Printer_state) :=
        case
            Printer_state == S0 && BP_state == S1 : S1; // Print command received
            Printer_state == S1 : S0; // Article printed
            default : Printer_state;
        esac;

    // Control block for simulation and checking
    control {
        var v : verification;
        v = simulate(10);
        v = check;
        print_results;
    }
}
