Here is how bytecode to create ready-initialised arrays of Inter data is emitted.

• §1. Introduction
• §2. Begin
• §4. Fill
• §5. End
• §6. Implementation

§1. Introduction. This section provides an API for the rest of the runtime and imperative modules to use when creating arrays of data in Inter memory. It's easy to use:

• ● Call EmitArrays::begin_word or one of its variants.
• ● Fill the array with its initial values.
• ● Call EmitArrays::end.

Unlike the API for emitting functions, this one is re-enterable: that is, a second array can independently be started while the first is still going on, provided that the second is completed before the first is resumes.

§2. Begin. Call exactly one of these functions. In each case the kind K is only weakly enforced; it's fine to store arbitrary data with K being NULL.

packaging_state EmitArrays::begin_word?Usage of EmitArrays::begin_word:
List Literals - §1
Box Quotations - §2
Instances - §4
Multimedia - §2.2, §3.2
Dialogue Beat Instances - §2, §2.9
Dialogue - §3
Dialogue Choice Instances - §3
Relations - §10
Kind Constructors - §32.3.2
Kind IDs - §9.1
Test Scripts - §4
The Player - §1
The Map - §1(inter_name *name, kind *K) {
    packaging_state save = Packaging::enter_home_of(name);
    EmitArrays::begin_inner(name, K, FALSE, CONST_LIST_FORMAT_WORDS);
    return save;
}

packaging_state EmitArrays::begin_word_by_extent?Usage of EmitArrays::begin_word_by_extent:
Relations - §10.3(inter_name *name, kind *K) {
    packaging_state save = Packaging::enter_home_of(name);
    EmitArrays::begin_inner(name, K, FALSE, CONST_LIST_FORMAT_WORDS_BY_EXTENT);
    return save;
}

packaging_state EmitArrays::begin_unchecked?Usage of EmitArrays::begin_unchecked:
Default Values - §2.8
Short Names - §4
List Literals - §2
Text Literals - §1
Text Substitutions - §1
Relation Literals - §1
Stored Action Literals - §1
Version Number Literals - §1
Relations - §6.3, §7(inter_name *name) {
    packaging_state save = Packaging::enter_home_of(name);
    EmitArrays::begin_inner(name, NULL, TRUE, CONST_LIST_FORMAT_WORDS);
    return save;
}

packaging_state EmitArrays::begin_byte?Usage of EmitArrays::begin_byte:
Multimedia - §2.1
Tables - §2.2
Test Scripts - §4(inter_name *name, kind *K) {
    packaging_state save = Packaging::enter_home_of(name);
    EmitArrays::begin_inner(name, K, FALSE, CONST_LIST_FORMAT_BYTES);
    return save;
}

packaging_state EmitArrays::begin_byte_by_extent?Usage of EmitArrays::begin_byte_by_extent:
Relations - §10.3(inter_name *name, kind *K) {
    packaging_state save = Packaging::enter_home_of(name);
    EmitArrays::begin_inner(name, K, FALSE, CONST_LIST_FORMAT_BYTES_BY_EXTENT);
    return save;
}

packaging_state EmitArrays::begin_bounded?Usage of EmitArrays::begin_bounded:
Tables - §2.1.1, §2.1.1.1(inter_name *name, kind *K) {
    packaging_state save = Packaging::enter_home_of(name);
    EmitArrays::begin_inner(name, K, FALSE, CONST_LIST_FORMAT_B_WORDS);
    return save;
}

packaging_state EmitArrays::begin_verb?Usage of EmitArrays::begin_verb:
Command Grammars - §11(inter_name *name, kind *K) {
    packaging_state save = Packaging::enter_home_of(name);
    EmitArrays::begin_inner(name, K, FALSE, CONST_LIST_FORMAT_GRAMMAR);
    return save;
}

packaging_state EmitArrays::begin_inline?Usage of EmitArrays::begin_inline:
Door Instances - §6
Action Bitmap Property - §1
Name Properties - §4(inter_name *name, kind *K) {
    packaging_state save = Packaging::enter_home_of(name);
    EmitArrays::begin_inner(name, K, FALSE, CONST_LIST_FORMAT_INLINE);
    return save;
}

§3. Sum constants are not really arrays at all, but for difficult reasons to do with linking we store them as such for now. The idea is that we want a constant like CONST1 + CONST2 + CONST3, in circumstances where we don't know those values right now — they may be defined in external kits of Inter code. We therefore cannot fold those into a constant value yet.

Instead we store this as if it were an array of three entries, with references to symbols to be defined externally.

packaging_state EmitArrays::begin_sum_constant?Usage of EmitArrays::begin_sum_constant:
Relations - §6.3.2(inter_name *name, kind *K) {
    packaging_state save = Packaging::enter_home_of(name);
    EmitArrays::begin_inner(name, K, FALSE, CONST_LIST_FORMAT_SUM);
    return save;
}

§4. Fill. Next call the following functions to add entries to the array. It's fine to mix and match the different sorts of entry: we're not trying to make something which would be a typesafe list in I7, so they can be absolutely any data.

void EmitArrays::numeric_entry?Usage of EmitArrays::numeric_entry:
The Heap - §6, §7
Default Values - §2.8, §2.8.1
List Literals - §1, §2
Box Quotations - §2
Relation Literals - §1
Stored Action Literals - §1
Version Number Literals - §1
Instances - §4
Multimedia - §2.1, §2.2, §3.2
Tables - §2.1.1.1.4, §2.2.3
Dialogue Beat Instances - §2, §2.1, §2.2, §2.4, §2.5, §2.6, §2.9, §3
Dialogue - §3.2, §3.3, §3.4, §3.6, §3.7, §3.8, §3.9
Dialogue Choice Instances - §3.2, §3.3, §3.4, §3.5
Relations - §6.3, §6.3.3, §7, §9, §10.2, §10.3
Kind Constructors - §28, §32.3.2
Kind IDs - §9.1.1.1, §9.1.1.2
Test Scripts - §4
The Player - §1
The Map - §1
Action Bitmap Property - §1(inter_ti N) {
    EmitArrays::entry_inner(InterValuePairs::number(N));
}

void EmitArrays::iname_entry?Usage of EmitArrays::iname_entry:
The Heap - §6, §7
Short Names - §4
List Literals - §2, §7.1
Text Literals - §1
Text Substitutions - §1
Relation Literals - §1
Stored Action Literals - §1
Instances - §4
Door Instances - §6
Multimedia - §2.2, §3.2
Tables - §2.1.1, §2.1.1.1.3, §2.1.1.1.5
Dialogue Beat Instances - §2, §2.1, §2.2, §2.3, §2.4, §2.5, §2.6, §3
Dialogue - §3.2, §3.3, §3.4, §3.5, §3.6, §3.7, §3.8
Dialogue Choice Instances - §3.3, §3.4
Relations - §6.3.2, §6.3.2.1, §6.3.3, §6.3.6, §7, §10.2
Kind Constructors - §28
Kind IDs - §6, §9.1
Test Scripts - §4
The Player - §1
The Map - §1
Command Grammar Lines - §6.1, §6.4, §7, §8, §10, §14.4, §14.5
Command Grammar Tokens - §1.3, §1.4.3, §1.5
Noun Filter Tokens - §5(inter_name *iname) {
    inter_symbol *alias;
    if (iname == NULL) alias = InterNames::to_symbol(Hierarchy::find(NOTHING_HL));
    else alias = InterNames::to_symbol(iname);
    EmitArrays::entry_inner(Emit::symbol_to_value_pair(alias));
}

void EmitArrays::null_entry?Usage of EmitArrays::null_entry:
Relation Literals - §1
Multimedia - §2.2
Tables - §2.1.1.1.3
Relations - §6.3, §7(void) {
    EmitArrays::iname_entry(Hierarchy::find(NULL_HL));
}

void EmitArrays::text_entry?Usage of EmitArrays::text_entry:
Responses - §6
Relation Literals - §1
Multimedia - §2.2, §3.2
Relations - §6.3.1, §6.3.5, §7(text_stream *content) {
    inter_pair val = InterValuePairs::from_text(Emit::at(), content);
    EmitArrays::entry_inner(val);
}

void EmitArrays::dword_entry?Usage of EmitArrays::dword_entry:
Command Grammars - §11
Command Grammar Lines - §2
Command Grammar Tokens - §1.1
Name Properties - §4(text_stream *content) {
    inter_pair val = InterValuePairs::from_singular_dword(Emit::at(), content);
    EmitArrays::entry_inner(val);
}

void EmitArrays::plural_dword_entry?Usage of EmitArrays::plural_dword_entry:
Name Properties - §4(text_stream *content) {
    inter_pair val = InterValuePairs::from_plural_dword(Emit::at(), content);
    EmitArrays::entry_inner(val);
}

void EmitArrays::generic_entry?Usage of EmitArrays::generic_entry:
Default Values - §1, §2.8.1
Tables - §2.1.1.1.4
Variables - §15(inter_pair val) {
    EmitArrays::entry_inner(val);
}

§5. End. And then call this to conclude:

void EmitArrays::end?Usage of EmitArrays::end:
Default Values - §2.8
Short Names - §4
List Literals - §1, §2
Text Literals - §1
Text Substitutions - §1
Box Quotations - §2
Relation Literals - §1
Stored Action Literals - §1
Version Number Literals - §1
Instances - §4
Door Instances - §6
Multimedia - §2.1, §2.2, §3.2
Tables - §2.1.1, §2.1.1.1, §2.2
Dialogue Beat Instances - §2, §2.9
Dialogue - §3
Dialogue Choice Instances - §3
Relations - §6.3, §6.3.2, §7, §10, §10.3
Kind Constructors - §32.3.2
Kind IDs - §9.1
Test Scripts - §4
The Player - §1
The Map - §1
Action Bitmap Property - §1
Command Grammars - §11
Name Properties - §4(packaging_state save) {
    EmitArrays::end_inner();
    Packaging::exit(Emit::tree(), save);
}

§6. Implementation. The rest of this section is not part of the public API, and shouldn't be called.

The implementation would be easy if it weren't for the re-enterability, which means we have to store an arbitrary number of half-finished arrays in memory. We do this with a stack of these objects, one for each such array:

typedef struct nascent_array {
    struct inter_symbol *array_name_symbol;
    struct kind *entry_kind;
    inter_ti array_form;
    int space_used;
    int capacity;
    inter_pair *entry_storage;
    CLASS_DEFINITION
} nascent_array;

lifo_stack *emission_array_stack = NULL;  of nascent_array

nascent_array *EmitArrays::current?Usage of EmitArrays::current:
§9(void) {
    if (emission_array_stack)
        return TOP_OF_LIFO_STACK(nascent_array, emission_array_stack);
    return NULL;
}

• The structure nascent_array is accessed in 4/ll and here.

§7. Until 2021, Inform went to some trouble to re-use these objects in memory. The memory saving was not worth the complexity and now we simply throw them away after each use.

nascent_array *EmitArrays::push_new?Usage of EmitArrays::push_new:
§8(void) {
    if (emission_array_stack == NULL)
        emission_array_stack = NEW_LIFO_STACK(nascent_array);
    nascent_array *A = CREATE(nascent_array);
    A->capacity = 0;
    A->space_used = 0;
    A->entry_kind = NULL;
    A->array_name_symbol = NULL;
    A->array_form = CONST_LIST_FORMAT_WORDS;
    A->entry_storage = NULL;
    PUSH_TO_LIFO_STACK(A, nascent_array, emission_array_stack);
    return A;
}

nascent_array *EmitArrays::pull?Usage of EmitArrays::pull:
§10(void) {
    if (emission_array_stack)
        return PULL_FROM_LIFO_STACK(nascent_array, emission_array_stack);
    internal_error("no array stack");
    return NULL;
}

§8. The various ways an array can begin all merge into this function:

void EmitArrays::begin_inner?Usage of EmitArrays::begin_inner:
§2, §3(inter_name *N, kind *K, int unchecked, inter_ti format) {
    inter_symbol *symb = InterNames::to_symbol(N);
    nascent_array *current_A = EmitArrays::push_new();
    current_A->entry_kind = (unchecked)?NULL:(K?K:K_value);
    current_A->array_name_symbol = symb;
    current_A->array_form = format;
}

§9. And the various ways to add an entry merge into this one:

void EmitArrays::entry_inner?Usage of EmitArrays::entry_inner:
§4(inter_pair val) {
    nascent_array *current_A = EmitArrays::current();
    if (current_A == NULL) internal_error("no nascent array");
    int N = current_A->space_used;
    if (N >= current_A->capacity) Quadruple the available storage9.1;
    current_A->entry_storage[current_A->space_used++] = val;
}

§9.1. Quadruple the available storage9.1 =

    int M = 4*(N+1);
    if (current_A->capacity == 0) M = 16;
    inter_pair *old_storage = current_A->entry_storage;
    current_A->entry_storage = Memory::calloc(M, sizeof(inter_pair), EMIT_ARRAY_MREASON);
    for (int i=0; i<current_A->capacity; i++) current_A->entry_storage[i] = old_storage[i];
    if (old_storage) Memory::I7_array_free(old_storage, EMIT_ARRAY_MREASON,
        current_A->capacity, sizeof(inter_pair));
    current_A->capacity = M;

• This code is used in §9.

§10. There is just one way to end. This is the only point at which any Inter bytecode is actually emitted, in a single burst, and that ensures that one array is completely emitted before another one is.

void EmitArrays::end_inner?Usage of EmitArrays::end_inner:
§5(void) {
    nascent_array *current_A = EmitArrays::pull();
    if (current_A == NULL) internal_error("no nascent array");
    inter_symbol *con_s = current_A->array_name_symbol;
    kind *K = current_A->entry_kind;
    inter_ti CID = InterTypes::to_TID(InterBookmark::scope(Emit::at()), InterTypes::unchecked());
    if (K) {
        inter_symbol *con_kind = NULL;
        if (ConstantInstruction::is_a_genuine_list_format(current_A->array_form))
            con_kind = Produce::kind_to_symbol(Kinds::unary_con(CON_list_of, K));
        else
            con_kind = Produce::kind_to_symbol(K);
        if (con_kind) CID = Emit::symbol_id(con_kind);
    }
    inter_tree_node *array_in_progress =
        Inode::new_with_3_data_fields(Emit::at(), CONSTANT_IST, Emit::symbol_id(con_s), CID,
            current_A->array_form, NULL, Emit::baseline());
    int pos = array_in_progress->W.extent;
    Inode::extend_instruction_by(array_in_progress, (unsigned int) (2*(current_A->space_used)));
    for (int i=0; i<current_A->space_used; i++, pos += 2)
        InterValuePairs::set(array_in_progress, pos, current_A->entry_storage[i]);
    Produce::guard(VerifyingInter::instruction(
        Emit::package(), array_in_progress));
    NodePlacement::move_to_moving_bookmark(array_in_progress, Emit::at());
}