Binary predicates for spatial relationships.

§1. So this section of code is all about the following:

binary_predicate *R_dialogue_containment = NULL;

§2. These relations are all hard-wired in:

void DialogueRelations::start(void) {
    METHOD_ADD(dialogue_bp_family, STOCK_BPF_MTID, DialogueRelations::stock);
    METHOD_ADD(dialogue_bp_family, TYPECHECK_BPF_MTID, DialogueRelations::typecheck);
    METHOD_ADD(dialogue_bp_family, ASSERT_BPF_MTID, DialogueRelations::assert);
    METHOD_ADD(dialogue_bp_family, DESCRIBE_FOR_INDEX_BPF_MTID,
        DialogueRelations::describe_for_index);
}

void DialogueRelations::stock(bp_family *self, int n) {
    if (n == 1) {
        R_dialogue_containment =
            BinaryPredicates::make_pair(spatial_bp_family,
                BPTerms::new(KindSubjects::from_kind(K_dialogue_beat)),
                BPTerms::new(KindSubjects::from_kind(K_value)),
                I"dialogue-contains", I"in-dialogue",
                NULL, Calculus::Schemas::new("DirectorTestContainment(*2,*1,*#2,*#1)"),
                PreformUtilities::wording(<relation-names>,
                    DIALOGUE_CONTAINMENT_RELATION_NAME));
        BinaryPredicates::set_index_details(R_dialogue_containment, NULL, "dialogue line");
    }
}

§3. No special rules apply to typechecking:

int DialogueRelations::typecheck(bp_family *self, binary_predicate *bp,
        kind **kinds_of_terms, kind **kinds_required, tc_problem_kit *tck) {
    if ((K_dialogue_beat) &&
        (Kinds::compatible(kinds_of_terms[1], K_dialogue_beat) == NEVER_MATCH)) {
        LOG("Term 0 is %u not %u\n", kinds_of_terms[1], K_dialogue_beat);
        TypecheckPropositions::issue_bp_typecheck_error(bp,
            kinds_of_terms[0], kinds_of_terms[1], tck);
        return NEVER_MATCH;
    }
    if (((K_dialogue_line) || (K_dialogue_choice)) &&
        (Kinds::compatible(kinds_of_terms[0], K_dialogue_line) == NEVER_MATCH) &&
        (Kinds::compatible(kinds_of_terms[0], K_dialogue_choice) == NEVER_MATCH)) {
        LOG("Term 0 is %u not %u\n", kinds_of_terms[0], kinds_required[0]);
        TypecheckPropositions::issue_bp_typecheck_error(bp,
            kinds_of_terms[0], kinds_of_terms[1], tck);
        return NEVER_MATCH;
    }
    return ALWAYS_MATCH;
}

§4. "In" requires delicate handling, because of the way that English uses it sometimes transitively and sometimes not. "The passport is in the desk", "The passport is in the Dining Room" and "The passport is in Venezuela" place the same object in a container, a room or a region respectively.

int DialogueRelations::assert(bp_family *self, binary_predicate *bp,
        inference_subject *infs0, parse_node *spec0,
        inference_subject *infs1, parse_node *spec1) {
    StandardProblems::sentence_problem(Task::syntax_tree(), _p_(PM_AssertedDialogueContainment),
        "this asks to specify how dialogue is structured",
        "but that has to be done by writing a script in which the structure "
        "is implicit.");
    return TRUE;
}

§5. Cursory description. 

void DialogueRelations::describe_for_index(bp_family *self, OUTPUT_STREAM,
    binary_predicate *bp) {
    WRITE("dialogue");
}