To manage tree structures of inter code, and manage the movement of nodes within these trees.

§1.

typedef struct inter_tree {
    struct inter_warehouse *housed;
    struct inter_tree_node *root_node;
    struct inter_package *root_package;
    struct building_site site;
    CLASS_DEFINITION
} inter_tree;

• The structure inter_tree is accessed in 2/bkm, 2/st, 2/pck, 2/trn, 3/iibf and here.

§2.

inter_tree *InterTree::new(void) {
    inter_tree *I = CREATE(inter_tree);
    I->housed = Inter::Warehouse::new();
    inter_ti N = Inter::Warehouse::create_symbols_table(I->housed);
    inter_symbols_table *globals = Inter::Warehouse::get_symbols_table(I->housed, N);
    inter_ti root_package_ID = Inter::Warehouse::create_package(I->housed, I);
    I->root_package = Inter::Warehouse::get_package(I->housed, root_package_ID);
    I->root_node = Inode::root_frame(I->housed, I);
    I->root_package->package_head = I->root_node;
    Inter::Packages::make_rootlike(I->root_package);
    Inter::Packages::set_scope(I->root_package, globals);
    I->root_node->package = I->root_package;
    Inter::Warehouse::attribute_resource(I->housed, N, I->root_package);
    Site::clear(I);
    return I;
}

inter_package *InterTree::root_package?Usage of InterTree::root_package:
Definition - §3
Inter in Binary Files - §1.4(inter_tree *I) {
    if (I) return I->root_package;
    return NULL;
}

inter_warehouse *InterTree::warehouse?Usage of InterTree::warehouse:
Bookmarks - §1
Inter Nodes - §4
Symbols - §4
Definition - §3
Inter in Binary Files - §1, §1.1
Inter Data Types - §3(inter_tree *I) {
    return I->housed;
}

inter_symbols_table *InterTree::global_scope?Usage of InterTree::global_scope:
Bookmarks - §1
Inter Nodes - §3
Symbols Tables - §8, §9, §11
Transmigration - §3, §3.1, §3.1.1, §3.2, §3.2.1
Inter in Binary Files - §1.4
The Package Construct - §2
The Inv Construct - §2(inter_tree *I) {
    return Inter::Packages::scope(I->root_package);
}

inter_tree_node *InterTree::previous?Usage of InterTree::previous:
§3.1, §3.5(inter_tree_node *F) {
    if (F == NULL) return NULL;
    return F->previous_itn;
}

inter_tree_node *InterTree::next?Usage of InterTree::next:
§3.1, §3.4, §5(inter_tree_node *F) {
    if (F == NULL) return NULL;
    return F->next_itn;
}

inter_tree_node *InterTree::first_child?Usage of InterTree::first_child:
§3.1, §3.2, §3.5, §5(inter_tree_node *F) {
    if (F == NULL) return NULL;
    return F->first_child_itn;
}

inter_tree_node *InterTree::second_child(inter_tree_node *P) {
    if (P == NULL) return NULL;
    P = P->first_child_itn;
    if (P == NULL) return NULL;
    return P->next_itn;
}

inter_tree_node *InterTree::third_child(inter_tree_node *P) {
    if (P == NULL) return NULL;
    P = P->first_child_itn;
    if (P == NULL) return NULL;
    P = P->next_itn;
    if (P == NULL) return NULL;
    return P->next_itn;
}

inter_tree_node *InterTree::fourth_child(inter_tree_node *P) {
    if (P == NULL) return NULL;
    P = P->first_child_itn;
    if (P == NULL) return NULL;
    P = P->next_itn;
    if (P == NULL) return NULL;
    P = P->next_itn;
    if (P == NULL) return NULL;
    return P->next_itn;
}

inter_tree_node *InterTree::fifth_child(inter_tree_node *P) {
    if (P == NULL) return NULL;
    P = P->first_child_itn;
    if (P == NULL) return NULL;
    P = P->next_itn;
    if (P == NULL) return NULL;
    P = P->next_itn;
    if (P == NULL) return NULL;
    P = P->next_itn;
    if (P == NULL) return NULL;
    return P->next_itn;
}

inter_tree_node *InterTree::sixth_child(inter_tree_node *P) {
    if (P == NULL) return NULL;
    P = P->first_child_itn;
    if (P == NULL) return NULL;
    P = P->next_itn;
    if (P == NULL) return NULL;
    P = P->next_itn;
    if (P == NULL) return NULL;
    P = P->next_itn;
    if (P == NULL) return NULL;
    P = P->next_itn;
    if (P == NULL) return NULL;
    return P->next_itn;
}

inter_tree_node *InterTree::last_child?Usage of InterTree::last_child:
§3.1, §3.3, §3.4
Bookmarks - §1(inter_tree_node *F) {
    if (F == NULL) return NULL;
    return F->last_child_itn;
}

inter_tree_node *InterTree::parent?Usage of InterTree::parent:
§3.1, §3.4, §3.5
Bookmarks - §1
Inter Nodes - §6
Packages - §3
Inter Errors - §2(inter_tree_node *F) {
    if (F == NULL) return NULL;
    return F->parent_itn;
}

§3.

void InterTree::remove_node?Usage of InterTree::remove_node:
Symbols - §4(inter_tree_node *P) {
    InterTree::place(P, NOWHERE_ICPLACEMENT, NULL);
}

void InterTree::place?Usage of InterTree::place:
Bookmarks - §1(inter_tree_node *C, int how, inter_tree_node *R) {
    Extricate C from its current tree position3.1;
    switch (how) {
        case NOWHERE_ICPLACEMENT:
            return;
        case AS_FIRST_CHILD_OF_ICPLACEMENT:
            Make C the first child of R3.2;
            break;
        case AS_LAST_CHILD_OF_ICPLACEMENT:
            Make C the last child of R3.3;
            break;
        case AFTER_ICPLACEMENT:
        case IMMEDIATELY_AFTER_ICPLACEMENT:
            Insert C after R3.4;
            break;
        case BEFORE_ICPLACEMENT:
            Insert C before R3.5;
            break;
        default:
            internal_error("unimplemented");
    }
}

§3.1. Extricate C from its current tree position3.1 =

    inter_tree_node *OP = InterTree::parent(C);
    if (OP) {
        if (InterTree::first_child(OP) == C)
            InterTree::set_first_child_UNSAFE(OP, InterTree::next(C));
        if (InterTree::last_child(OP) == C)
            InterTree::set_last_child_UNSAFE(OP, InterTree::previous(C));
    }
    inter_tree_node *OB = InterTree::previous(C);
    inter_tree_node *OD = InterTree::next(C);
    if (OB) {
        InterTree::set_next_UNSAFE(OB, OD);
    }
    if (OD) {
        InterTree::set_previous_UNSAFE(OD, OB);
    }
    InterTree::set_parent_UNSAFE(C, NULL);
    InterTree::set_previous_UNSAFE(C, NULL);
    InterTree::set_next_UNSAFE(C, NULL);

• This code is used in §3.

§3.2. Make C the first child of R3.2 =

    InterTree::set_parent_UNSAFE(C, R);
    inter_tree_node *D = InterTree::first_child(R);
    if (D == NULL) {
        InterTree::set_last_child_UNSAFE(R, C);
        InterTree::set_next_UNSAFE(C, NULL);
    } else {
        InterTree::set_previous_UNSAFE(D, C);
        InterTree::set_next_UNSAFE(C, D);
    }
    InterTree::set_first_child_UNSAFE(R, C);

• This code is used in §3.

§3.3. Make C the last child of R3.3 =

    InterTree::set_parent_UNSAFE(C, R);
    inter_tree_node *B = InterTree::last_child(R);
    if (B == NULL) {
        InterTree::set_first_child_UNSAFE(R, C);
        InterTree::set_previous_UNSAFE(C, NULL);
    } else {
        InterTree::set_next_UNSAFE(B, C);
        InterTree::set_previous_UNSAFE(C, B);
    }
    InterTree::set_last_child_UNSAFE(R, C);

• This code is used in §3.

§3.4. Insert C after R3.4 =

    inter_tree_node *P = InterTree::parent(R);
    if (P == NULL) internal_error("can't move C before R when R is nowhere");
    InterTree::set_parent_UNSAFE(C, P);
    if (InterTree::last_child(P) == R)
        InterTree::set_last_child_UNSAFE(P, C);
    else {
        inter_tree_node *D = InterTree::next(R);
        if (D == NULL) internal_error("inter tree broken");
        InterTree::set_next_UNSAFE(C, D);
        InterTree::set_previous_UNSAFE(D, C);
    }
    InterTree::set_next_UNSAFE(R, C);
    InterTree::set_previous_UNSAFE(C, R);

• This code is used in §3.

§3.5. Insert C before R3.5 =

    inter_tree_node *P = InterTree::parent(R);
    if (P == NULL) internal_error("can't move C before R when R is nowhere");
    InterTree::set_parent_UNSAFE(C, P);
    if (InterTree::first_child(P) == R)
        InterTree::set_first_child_UNSAFE(P, C);
    else {
        inter_tree_node *B = InterTree::previous(R);
        if (B == NULL) internal_error("inter tree broken");
        InterTree::set_previous_UNSAFE(C, B);
        InterTree::set_next_UNSAFE(B, C);
    }
    InterTree::set_next_UNSAFE(C, R);
    InterTree::set_previous_UNSAFE(R, C);

• This code is used in §3.

§4.

void InterTree::set_previous_UNSAFE?Usage of InterTree::set_previous_UNSAFE:
§3.1, §3.2, §3.3, §3.4, §3.5(inter_tree_node *F, inter_tree_node *V) {
    if (F) F->previous_itn = V;
}

void InterTree::set_next_UNSAFE?Usage of InterTree::set_next_UNSAFE:
§3.1, §3.2, §3.3, §3.4, §3.5(inter_tree_node *F, inter_tree_node *V) {
    if (F) F->next_itn = V;
}

void InterTree::set_first_child_UNSAFE?Usage of InterTree::set_first_child_UNSAFE:
§3.1, §3.2, §3.3, §3.5(inter_tree_node *F, inter_tree_node *V) {
    if (F) F->first_child_itn = V;
}

void InterTree::set_last_child_UNSAFE?Usage of InterTree::set_last_child_UNSAFE:
§3.1, §3.2, §3.3, §3.4(inter_tree_node *F, inter_tree_node *V) {
    if (F) F->last_child_itn = V;
}

void InterTree::set_parent_UNSAFE?Usage of InterTree::set_parent_UNSAFE:
§3.1, §3.2, §3.3, §3.4, §3.5(inter_tree_node *F, inter_tree_node *V) {
    if (F) F->parent_itn = V;
}

§5.

define LOOP_THROUGH_INTER_CHILDREN(F, P)
    for (inter_tree_node *F = InterTree::first_child(P); F; F = InterTree::next(F))
define PROTECTED_LOOP_THROUGH_INTER_CHILDREN(F, P)
    for (inter_tree_node *F = InterTree::first_child(P), *FN = F?(InterTree::next(F)):NULL;
        F; F = FN, FN = FN?(InterTree::next(FN)):NULL)

void InterTree::traverse_root_only?Usage of InterTree::traverse_root_only:
Inter in Binary Files - §1.1.5
Inter in Text Files - §2(inter_tree *from, void (*visitor)(inter_tree *, inter_tree_node *, void *), void *state, int filter) {
    PROTECTED_LOOP_THROUGH_INTER_CHILDREN(P, from->root_node) {
        if ((filter == 0) ||
            ((filter > 0) && (P->W.data[ID_IFLD] == (inter_ti) filter)) ||
            ((filter < 0) && (P->W.data[ID_IFLD] != (inter_ti) -filter)))
            (*visitor)(from, P, state);
    }
}

void InterTree::traverse?Usage of InterTree::traverse:
Symbols Tables - §10
Transmigration - §1.4, §1.5
Inter in Binary Files - §1.1.5
Inter in Text Files - §1, §2(inter_tree *from, void (*visitor)(inter_tree *, inter_tree_node *, void *), void *state, inter_package *mp, int filter) {
    if (mp == NULL) mp = Site::main_package_if_it_exists(from);
    if (mp) {
        inter_tree_node *D = Inter::Packages::definition(mp);
        if ((filter == 0) ||
            ((filter > 0) && (D->W.data[ID_IFLD] == (inter_ti) filter)) ||
            ((filter < 0) && (D->W.data[ID_IFLD] != (inter_ti) -filter)))
            (*visitor)(from, D, state);
        InterTree::traverse_r(from, D, visitor, state, filter);
    }
}
void InterTree::traverse_r(inter_tree *from, inter_tree_node *P, void (*visitor)(inter_tree *, inter_tree_node *, void *), void *state, int filter) {
    PROTECTED_LOOP_THROUGH_INTER_CHILDREN(C, P) {
        if ((filter == 0) ||
            ((filter > 0) && (C->W.data[ID_IFLD] == (inter_ti) filter)) ||
            ((filter < 0) && (C->W.data[ID_IFLD] != (inter_ti) -filter)))
            (*visitor)(from, C, state);
        InterTree::traverse_r(from, C, visitor, state, filter);
    }
}

§6.

define LOOP_THROUGH_SUBPACKAGES(entry, pack, ptype)
    inter_symbol *pack##wanted = (pack)?(PackageTypes::get(pack->package_head->tree, ptype)):NULL;
    if (pack)
        LOOP_THROUGH_INTER_CHILDREN(C, Inter::Packages::definition(pack))
            if ((C->W.data[ID_IFLD] == PACKAGE_IST) &&
                (entry = Inter::Package::defined_by_frame(C)) &&
                (Inter::Packages::type(entry) == pack##wanted))

int InterTree::no_subpackages(inter_package *pack, text_stream *ptype) {
    int N = 0;
    if (pack) {
        inter_package *entry;
        LOOP_THROUGH_SUBPACKAGES(entry, pack, ptype) N++;
    }
    return N;
}