A plugin giving minimal support for switchable devices.

§1. The Devices plugin does just one thing: it applies an indicator property to things of the kind "device". This used to be accomplished by the Standard Rules in a clumsy sort of way (with a direct I6 code injection), but in the age of Inter we want to avoid that sort of tomfoolery. 

    kind *K_device = NULL;
    property *P_switchable = NULL;

§2. 

    void PL::Devices::start(void) {
        PLUGIN_REGISTER(PLUGIN_NEW_BASE_KIND_NOTIFY, PL::Devices::devices_new_base_kind_notify);
        PLUGIN_REGISTER(PLUGIN_COMPLETE_MODEL, PL::Devices::IF_complete_model);
    }

The function PL::Devices::start appears nowhere else.

§3. 

    <notable-device-kinds> ::=
        device

§4. 

    int PL::Devices::devices_new_base_kind_notify(kind *new_base, text_stream *name, wording W) {
        if (<notable-device-kinds>(W)) { K_device = new_base; return TRUE; }
        return FALSE;
    }

The function PL::Devices::devices_new_base_kind_notify is used in §2.

§5. 

    int PL::Devices::IF_complete_model(int stage) {
        if (stage == 3) {
            P_switchable = Properties::EitherOr::new_nameless(L"switchable");
            Properties::EitherOr::implement_as_attribute(P_switchable, TRUE);
            instance *I;
            LOOP_OVER_OBJECT_INSTANCES(I)
                if (Instances::of_kind(I, K_device))
                    Properties::EitherOr::assert(
                        P_switchable, Instances::as_subject(I), TRUE, CERTAIN_CE);
        }
        return FALSE;
    }

The function PL::Devices::IF_complete_model is used in §2.