Defining the package construct.

• §1. Definition
• §2. Instructions
• §6. Creating from textual Inter syntax
• §7. Writing to textual Inter syntax
• §9. Package vs its head vs its name symbol

§1. Definition. For what this does and why it is used, see Textual Inter (in inter).

void PackageInstruction::define_construct?Usage of PackageInstruction::define_construct:
Inter Constructs - §15(void) {
    inter_construct *IC = InterInstruction::create_construct(PACKAGE_IST, I"package");
    InterInstruction::defines_symbol_in_fields(IC, DEFN_PACKAGE_IFLD, TYPE_PACKAGE_IFLD);
    InterInstruction::specify_syntax(IC, I"package TOKENS _IDENTIFIER");
    InterInstruction::data_extent_always(IC, 5);
    InterInstruction::permit(IC, OUTSIDE_OF_PACKAGES_ICUP);
    InterInstruction::permit(IC, INSIDE_PLAIN_PACKAGE_ICUP);
    InterInstruction::permit(IC, CAN_HAVE_CHILDREN_ICUP);
    METHOD_ADD(IC, CONSTRUCT_READ_MTID, PackageInstruction::read);
    METHOD_ADD(IC, CONSTRUCT_TRANSPOSE_MTID, PackageInstruction::transpose);
    METHOD_ADD(IC, CONSTRUCT_VERIFY_MTID, PackageInstruction::verify);
    METHOD_ADD(IC, CONSTRUCT_WRITE_MTID, PackageInstruction::write);
    METHOD_ADD(IC, CONSTRUCT_VERIFY_CHILDREN_MTID, PackageInstruction::verify_children);
}

§2. Instructions. In bytecode, the frame of a package instruction is laid out with the compulsory words — see Inter Nodes — followed by:

define DEFN_PACKAGE_IFLD    (DATA_IFLD + 0)
define TYPE_PACKAGE_IFLD    (DATA_IFLD + 1)
define PTYPE_PACKAGE_IFLD   (DATA_IFLD + 2)
define SYMBOLS_PACKAGE_IFLD (DATA_IFLD + 3)
define PID_PACKAGE_IFLD     (DATA_IFLD + 4)

§3. If you try to create uniquely-named subpackages all called bag inside the same package, you'll get bag, then bag_1, bag_2, and so on.

inter_error_message *PackageInstruction::new?Usage of PackageInstruction::new:
§6(inter_bookmark *IBM,
    text_stream *name, inter_type type, int uniquely, inter_symbol *ptype_name, inter_ti level,
    inter_error_location *eloc, inter_package **created) {
    inter_error_message *E;
    if (uniquely) {
        TEMPORARY_TEXT(mutable)
        WRITE_TO(mutable, "%S", name);
        inter_package *pack;
        int N = 1, A = 0;
        while ((pack = InterPackage::from_name(InterBookmark::package(IBM), mutable)) != NULL) {
            TEMPORARY_TEXT(TAIL)
            WRITE_TO(TAIL, "_%d", N++);
            if (A > 0) Str::truncate(mutable, Str::len(mutable) - A);
            A = Str::len(TAIL);
            WRITE_TO(mutable, "%S", TAIL);
            Str::truncate(mutable, 31);
            DISCARD_TEXT(TAIL)
        }
        E = PackageInstruction::new_inner(IBM, mutable, type, ptype_name, level, eloc, created);
        DISCARD_TEXT(mutable)
    } else {
        E = PackageInstruction::new_inner(IBM, name, type, ptype_name, level, eloc, created);
    }
    return E;
}

§4. The actual instruction is made here:

inter_error_message *PackageInstruction::new_inner?Usage of PackageInstruction::new_inner:
§3(inter_bookmark *IBM,
    text_stream *name_text, inter_type type, inter_symbol *ptype_name, inter_ti level,
    inter_error_location *eloc, inter_package **created) {
    inter_tree *I = InterBookmark::tree(IBM);
    inter_warehouse *warehouse = InterBookmark::warehouse(IBM);
    inter_ti STID = InterWarehouse::create_symbols_table(warehouse);
    inter_error_message *E = NULL;
    inter_symbol *package_name =
        TextualInter::new_symbol(eloc, InterBookmark::scope(IBM), name_text, &E);
    if (E) return E;
    inter_tree_node *P = Inode::new_with_5_data_fields(IBM, PACKAGE_IST,
        /* DEFN_PACKAGE_IFLD: */    InterSymbolsTable::id_at_bookmark(IBM, package_name),
        /* TYPE_PACKAGE_IFLD: */    InterTypes::to_TID_at(IBM, type),
        /* PTYPE_PACKAGE_IFLD: */   InterSymbolsTable::id_from_symbol(I, NULL, ptype_name),
        /* SYMBOLS_PACKAGE_IFLD: */ STID,
        /* PID_PACKAGE_IFLD: */     0,  but see just below...
        eloc, level);
    inter_ti PID = InterWarehouse::create_package(warehouse, I);
    inter_package *pack = InterWarehouse::get_package(warehouse, PID);
    pack->package_head = P;
    P->W.instruction[PID_PACKAGE_IFLD] = PID;
    InterPackage::set_scope(pack, InterWarehouse::get_symbols_table(warehouse, STID));
    InterWarehouse::set_symbols_table_owner(warehouse, STID, pack);

    E = VerifyingInter::instruction(InterBookmark::package(IBM), P);
    if (E) return E;
    NodePlacement::move_to_moving_bookmark(P, IBM);

    LargeScale::note_package_name(I, pack, name_text);
    if (Str::eq(InterSymbol::identifier(ptype_name), I"_code"))
        InterPackage::mark_as_a_function_body(pack);
    if (Str::eq(InterSymbol::identifier(ptype_name), I"_linkage"))
        InterPackage::mark_as_a_linkage_package(pack);

    if (created) *created = pack;
    LOGIF(INTER_SYMBOLS, "Package $6 at IBM $5\n", pack, IBM);

    return NULL;
}

void PackageInstruction::transpose?Usage of PackageInstruction::transpose:
§1(inter_construct *IC, inter_tree_node *P, inter_ti *grid,
    inter_ti grid_extent, inter_error_message **E) {
    P->W.instruction[PID_PACKAGE_IFLD] = grid[P->W.instruction[PID_PACKAGE_IFLD]];
    P->W.instruction[SYMBOLS_PACKAGE_IFLD] = grid[P->W.instruction[SYMBOLS_PACKAGE_IFLD]];
}

§5. Verification begins with sanity checks, but then does something crucial: makes sure that the link between the package and its head node is in place. If the instruction has just been created by PackageInstruction::new then that will be done already — but not if the instruction has been loaded from a binary Inter file.

void PackageInstruction::verify?Usage of PackageInstruction::verify:
§1(inter_construct *IC, inter_tree_node *P, inter_package *owner,
    inter_error_message **E) {
    *E = VerifyingInter::SID_field(owner, P, DEFN_PACKAGE_IFLD, PACKAGE_IST);
    if (*E) return;
    *E = VerifyingInter::TID_field(owner, P, TYPE_PACKAGE_IFLD);
    if (*E) return;
    *E = VerifyingInter::GSID_field(P, PTYPE_PACKAGE_IFLD, PACKAGETYPE_IST);
    if (*E) return;
    *E = VerifyingInter::symbols_table_field(owner, P, SYMBOLS_PACKAGE_IFLD);
    if (*E) return;
    *E = VerifyingInter::package_field(owner, P, PID_PACKAGE_IFLD);
    if (*E) return;

    inter_package *pack = Inode::ID_to_package(P, P->W.instruction[PID_PACKAGE_IFLD]);
    if (pack) pack->package_head = P; else internal_error("no package in PID field");
}

void PackageInstruction::verify_children?Usage of PackageInstruction::verify_children:
§1(inter_construct *IC, inter_tree_node *P,
    inter_error_message **E) {
    if (InterPackage::is_a_function_body(PackageInstruction::at_this_head(P))) {
        LOOP_THROUGH_INTER_CHILDREN(C, P) {
            if ((C->W.instruction[0] != LABEL_IST) &&
                (C->W.instruction[0] != LOCAL_IST) &&
                (C->W.instruction[0] != CODE_IST) &&
                (C->W.instruction[0] != COMMENT_IST)) {
                *E = Inode::error(C, I"instruction not permitted at the top level", NULL);
                return;
            }
        }
    }
}

§6. Creating from textual Inter syntax.

void PackageInstruction::read?Usage of PackageInstruction::read:
§1(inter_construct *IC, inter_bookmark *IBM, inter_line_parse *ilp,
    inter_error_location *eloc, inter_error_message **E) {
    inter_symbol *ptype_name = LargeScale::package_type(InterBookmark::tree(IBM), ilp->mr.exp[1]);

    inter_type type = InterTypes::unchecked();
    text_stream *identifier = ilp->mr.exp[0];
    match_results mr = Regexp::create_mr();
    if (Regexp::match(&mr, identifier, U"%((%c+)%) (%c+)")) {
        type = InterTypes::parse_simple(InterBookmark::scope(IBM), eloc, mr.exp[0], E);
        identifier = mr.exp[1];
    }
    if (*E == NULL) {
        inter_package *pack = NULL;
        *E = PackageInstruction::new(IBM, identifier, type, FALSE, ptype_name,
            (inter_ti) ilp->indent_level, eloc, &pack);
        if (*E == NULL) InterBookmark::move_into_package(IBM, pack);
    }
    Regexp::dispose_of(&mr);
}

§7. Writing to textual Inter syntax.

void PackageInstruction::write?Usage of PackageInstruction::write:
§1(inter_construct *IC, OUTPUT_STREAM, inter_tree_node *P) {
    inter_package *pack = PackageInstruction::at_this_head(P);
    inter_symbol *ptype_name =
        InterSymbolsTable::global_symbol_from_ID_at_node(P, PTYPE_PACKAGE_IFLD);
    WRITE("package ");
    TextualInter::write_optional_type_marker(OUT, P, TYPE_PACKAGE_IFLD);
    WRITE("%S %S", InterPackage::name(pack), InterSymbol::identifier(ptype_name));
}

§8. With the addendum of writing out the pseudo-constructs plug and socket to ensure that any in the symbols table are recorded in the textual output:

inter_error_message *PackageInstruction::write_plugs_and_sockets?Usage of PackageInstruction::write_plugs_and_sockets:
Inter Constructs - §19(OUTPUT_STREAM,
    inter_tree_node *P) {
    inter_package *pack = PackageInstruction::at_this_head(P);
    if (pack) {
        inter_symbols_table *locals = InterPackage::scope(pack);
        int L = Inode::get_level(P) + 1;
        LOOP_OVER_SYMBOLS_TABLE(S, locals) {
            if (InterSymbol::is_plug(S)) {
                PlugInstruction::write_declaration(OUT, S, L);
                WRITE("\n");
            }
        }
        LOOP_OVER_SYMBOLS_TABLE(S, locals) {
            if (InterSymbol::is_socket(S)) {
                PlugInstruction::write_declaration(OUT, S, L);
                WRITE("\n");
            }
        }
    }
    return NULL;
}

§9. Package vs its head vs its name symbol. Three ways to identify a package, all inter-convertible.

int PackageInstruction::is(inter_symbol *package_name) {
    if (package_name == NULL) return FALSE;
    inter_tree_node *D = InterSymbol::definition(package_name);
    if (D == NULL) return FALSE;
    if (Inode::isnt(D, PACKAGE_IST)) return FALSE;
    return TRUE;
}

int PackageInstruction::is_function(inter_symbol *package_name) {
    if (package_name == NULL) return FALSE;
    inter_tree_node *D = InterSymbol::definition(package_name);
    return InterPackage::is_a_function_body(PackageInstruction::at_this_head(D));
}

inter_package *PackageInstruction::which(inter_symbol *package_name) {
    if (package_name == NULL) return NULL;
    inter_tree_node *D = InterSymbol::definition(package_name);
    if (D == NULL) return NULL;
    return Inode::ID_to_package(D, D->W.instruction[PID_PACKAGE_IFLD]);
}

inter_package *PackageInstruction::at_this_head?Usage of PackageInstruction::at_this_head:
§5, §7, §8
Inter Trees - §9
Bookmarks - §6
Packages - §5, §11, §20
Transmigration - §4.2, §5
Inter Constructs - §7
Inter in Text Files - §7(inter_tree_node *D) {
    if (D == NULL) return NULL;
    if (Inode::isnt(D, PACKAGE_IST)) return NULL;
    return Inode::ID_to_package(D, D->W.instruction[PID_PACKAGE_IFLD]);
}

inter_symbol *PackageInstruction::name_symbol?Usage of PackageInstruction::name_symbol:
Packages - §7
Transmigration - §3.4(inter_package *pack) {
    if (pack == NULL) return NULL;
    inter_tree_node *D = pack->package_head;
    inter_symbol *package_name =
        InterSymbolsTable::symbol_from_ID_at_node(D, DEFN_PACKAGE_IFLD);
    return package_name;
}

§10. And the type:

inter_symbol *PackageInstruction::get_type_of?Usage of PackageInstruction::get_type_of:
Packages - §8
Transmigration - §4.2.1(inter_tree *I, inter_tree_node *P) {
    if (Inode::is(P, PACKAGE_IST))
        return InterSymbolsTable::symbol_from_ID(
            InterTree::global_scope(I), P->W.instruction[PTYPE_PACKAGE_IFLD]);
    return NULL;
}

§11. These look invariant-busting and dubious: see Transmigration for why they are needed. And see also Functions (in imperative).

void PackageInstruction::set_type?Usage of PackageInstruction::set_type:
Transmigration - §4.2.1(inter_tree *I, inter_tree_node *P, inter_symbol *ptype) {
    if (Inode::is(P, PACKAGE_IST))
        P->W.instruction[PTYPE_PACKAGE_IFLD] = InterSymbolsTable::id_from_symbol(I, NULL, ptype);
    else internal_error("wrote primitive to non-primitive invocation");
}

void PackageInstruction::set_name_symbol?Usage of PackageInstruction::set_name_symbol:
Transmigration - §3.4(inter_package *pack, inter_symbol *S) {
    if (pack == NULL) internal_error("no package");
    inter_tree_node *D = pack->package_head;
    S->definition = D;
    inter_package *S_pack = InterSymbol::package(S);
    D->W.instruction[DEFN_PACKAGE_IFLD] =
        InterSymbolsTable::id_from_symbol_not_creating(InterPackage::tree(S_pack), S_pack, S);
}

void PackageInstruction::set_data_type(inter_package *pack, inter_type type) {
    if (pack == NULL) internal_error("no package");
    inter_tree_node *D = pack->package_head;
    D->W.instruction[TYPE_PACKAGE_IFLD] =
        InterTypes::to_TID(InterPackage::scope(InterPackage::parent(pack)), type);
}