To compile the activities submodule for a compilation unit, which contains _activity packages.

• §1. Compilation data
• §5. Compilation

§1. Compilation data. Each activity object contains this data:

typedef struct activity_compilation_data {
    struct package_request *av_package;  its _activity package
    struct inter_name *value_iname;      an identifier for a constant identifying this
    struct inter_name *variables_id;     ID for the shared variables set, if any
} activity_compilation_data;

• The structure activity_compilation_data is accessed in 4/rsp, 5/rls, 7/act and here.

§2. Which is created, long before compilation time, thus:

activity_compilation_data RTActivities::new_compilation_data(activity *av) {
    activity_compilation_data acd;
    acd.av_package = Hierarchy::local_package(ACTIVITIES_HAP);
    Hierarchy::apply_metadata_from_wording(acd.av_package, ACTIVITY_NAME_MD_HL, av->name);
    acd.value_iname = Hierarchy::make_iname_with_memo(ACTIVITY_VALUE_HL, acd.av_package, av->name);
    acd.variables_id = Hierarchy::make_iname_in(ACTIVITY_SHV_ID_HL, acd.av_package);
    return acd;
}

§3. Regarded as an rvalue, an activity compiles to this:

inter_name *RTActivities::iname(activity *av) {
    return av->compilation_data.value_iname;
}

§4. Three subpackages contain its three rulebooks, requested here:

package_request *RTActivities::rulebook_package(activity *av, int N) {
    package_request *pack = av->compilation_data.av_package;
    switch (N) {
        case 0: return Hierarchy::make_package_in(ACTIVITY_BEFORE_RB_HL, pack);
        case 1: return Hierarchy::make_package_in(ACTIVITY_FOR_RB_HL,    pack);
        case 2: return Hierarchy::make_package_in(ACTIVITY_AFTER_RB_HL,  pack);
    }
    internal_error("bad activity rulebook");
    return NULL;
}

§5. Compilation.

void RTActivities::compile(void) {
    activity *av;
    LOOP_OVER(av, activity) {
        text_stream *desc = Str::new();
        WRITE_TO(desc, "activity '%W'", av->name);
        Sequence::queue(&RTActivities::compilation_agent, STORE_POINTER_activity(av), desc);
    }
}

§6. So the following makes a single _activity package. As noted above, an activity compiles as a value to its value_iname, which will typically have a descriptive name such as V_printing_short_title. But this is equated below to another constant in the same package, always called activity_id. Those ID numbers must all be distinct at runtime, and this is arranged during linking: for now, we simply write 0.

void RTActivities::compilation_agent?Usage of RTActivities::compilation_agent:
§5(compilation_subtask *t) {
    activity *av = RETRIEVE_POINTER_activity(t->data);
    package_request *pack = av->compilation_data.av_package;

    inter_name *iname = Hierarchy::make_iname_in(ACTIVITY_ID_HL, pack);
    Emit::numeric_constant(iname, 0);  a placeholder: see above

    Emit::iname_constant(av->compilation_data.value_iname, K_value, iname);

    Hierarchy::apply_metadata_from_iname(pack, ACTIVITY_BEFORE_MD_HL,
        RTRulebooks::id_iname(av->before_rules));
    Hierarchy::apply_metadata_from_iname(pack, ACTIVITY_FOR_MD_HL,
        RTRulebooks::id_iname(av->for_rules));
    Hierarchy::apply_metadata_from_iname(pack, ACTIVITY_AFTER_MD_HL,
        RTRulebooks::id_iname(av->after_rules));
    Hierarchy::apply_metadata_from_number(pack, ACTIVITY_UFA_MD_HL,
        (inter_ti) Rulebooks::used_by_future_actions(av->before_rules));

    if (SharedVariables::set_empty(av->activity_variables) == FALSE) {
        inter_name *iname = Hierarchy::make_iname_in(ACTIVITY_VARC_FN_HL, pack);
        RTSharedVariables::compile_creator_fn(av->activity_variables, iname);
        Hierarchy::apply_metadata_from_iname(pack, ACTIVITY_VAR_CREATOR_MD_HL, iname);
    }
    Emit::numeric_constant(av->compilation_data.variables_id, 0);
}