To compile the main/synoptic/scenes submodule.

§1. Our inventory inv already contains a list inv->scene_nodes of all packages in the tree with type _instance which are of the kind K_scene. (These do not have ID numbers here because they already have instance_id values by virtue of being instances.) 

void SynopticScenes::compile(inter_tree *I, pipeline_step *step, tree_inventory *inv) {
    if (InterNodeList::array_len(inv->scene_nodes) > 0)
        InterNodeList::array_sort(inv->scene_nodes, MakeSynopticModuleStage::module_order);
    Define SHOWSCENESTATUS function1.1;
    Define DETECTSCENECHANGE function1.2;
}

§1.1. Define SHOWSCENESTATUS function1.1 = 

    inter_name *iname = HierarchyLocations::iname(I, SHOWSCENESTATUS_HL);
    Synoptic::begin_function(I, iname);
    for (int i=0; i<InterNodeList::array_len(inv->scene_nodes); i++) {
        inter_package *pack =
            PackageInstruction::at_this_head(inv->scene_nodes->list[i].node);
        inter_symbol *ssf_s = Metadata::required_symbol(pack, I"^scene_status_fn");
        Produce::inv_call_symbol(I, ssf_s);
    }
    Synoptic::end_function(I, step, iname);

§1.2. There is one argument, chs: the number of iterations so far. Iterations occur because each set of scene changes could change the circumstances in such a way that other scene changes are now required (through external conditions, not through anchors); we don't want this to lock up, so we will cap recursion. Within the function, a second local variable, ch, is a flag indicating whether any change in status has or has not occurred. 

define MAX_SCENE_CHANGE_ITERATION 20

Define DETECTSCENECHANGE function1.2 = 

    inter_name *iname = HierarchyLocations::iname(I, DETECTSCENECHANGE_HL);
    Synoptic::begin_function(I, iname);
    inter_symbol *chs_s = Synoptic::local(I, I"chs", NULL);
    inter_symbol *Again_l = Produce::reserve_label(I, I".Again");
    inter_symbol *CScene_l = Produce::reserve_label(I, I".CScene");
    Produce::place_label(I, Again_l);
    for (int i=0; i<InterNodeList::array_len(inv->scene_nodes); i++) {
        inter_package *pack =
            PackageInstruction::at_this_head(inv->scene_nodes->list[i].node);
        inter_symbol *scf_s = Metadata::required_symbol(pack, I"^scene_change_fn");
        Produce::inv_primitive(I, IF_BIP);
        Produce::down(I);
            Produce::inv_call_symbol(I, scf_s);
            Produce::code(I);
            Produce::down(I);
                Produce::inv_primitive(I, JUMP_BIP);
                Produce::down(I);
                    Produce::lab(I, CScene_l);
                Produce::up(I);
            Produce::up(I);
        Produce::up(I);
    }
    Produce::rfalse(I);

    Produce::place_label(I, CScene_l);

    Produce::inv_primitive(I, IF_BIP);
    Produce::down(I);
        Produce::inv_primitive(I, GT_BIP);
        Produce::down(I);
            Produce::val_symbol(I, K_value, chs_s);
            Produce::val(I, K_value,
                InterValuePairs::number((inter_ti) MAX_SCENE_CHANGE_ITERATION));
        Produce::up(I);
        Produce::code(I);
        Produce::down(I);
            Produce::inv_primitive(I, PRINT_BIP);
            Produce::down(I);
                Produce::val_text(I, I">--> The scene change machinery is stuck.\n");
            Produce::up(I);
            Produce::rtrue(I);
        Produce::up(I);
    Produce::up(I);
    Produce::inv_primitive(I, PREINCREMENT_BIP);
    Produce::down(I);
        Produce::ref_symbol(I, K_value, chs_s);
    Produce::up(I);
    Produce::inv_primitive(I, JUMP_BIP);
    Produce::down(I);
        Produce::lab(I, Again_l);
    Produce::up(I);
    Synoptic::end_function(I, step, iname);