"Emitting" is the process of generating Inter bytecode, and this section provides a comprehensive API for the runtime and imperative modules to do that.

• §1. The emission tree
• §2. Data as pairs of Inter bytes
• §4. Kinds
• §5. Pragmas
• §6. Constants
• §12. Instances
• §13. Variables
• §14. Properties and permissions
• §15. Property values
• §16. Interventions

§1. The emission tree. The bytecode module can maintain multiple independent trees of Inter code in memory, so that most calls to bytecode or building take an inter_tree pointer as their first function argument. But runtime and imperative work on just one single tree.

Calling LargeScale::begin_new_tree makes a minimum of package types, creates the main package, and so on, but leaves the tree basically still empty.

inter_tree *main_emission_tree = NULL;

inter_tree *Emit::create_emission_tree(void) {
    main_emission_tree = InterTree::new();
    LargeScale::begin_new_tree(main_emission_tree);
    return main_emission_tree;
}
inter_tree *Emit::tree?Usage of Emit::tree:
§4, §5, §6, §7, §8, §9, §11, §12, §13, §14
Hierarchy - §1, §2, §8, §9, §11, §12, §13, §14, §15, §16, §17, §18, §20, §21, §22
Compilation Units - §2.1
Emit Code - §2, §3, §4, §5, §7, §8, §10, §12, §13, §14, §15, §16, §17
Emit Arrays - §5
Default Values - §1
Generic Module - §1
Use Options - §3
Enclosures - §1
Text Substitutions - §7.4
Rules - §6
Variables - §6, §15
Literal Patterns - §7
Kind Constructors - §3, §9, §12, §17.1
Property Permissions - §2, §3
Property Values - §2, §2.2.1
Command Grammars - §7(void) {
    return main_emission_tree;
}

inter_ti Emit::symbol_id?Usage of Emit::symbol_id:
Emit Arrays - §10(inter_symbol *S) {
    return InterSymbolsTable::id_at_bookmark(Emit::at(), S);
}

inter_warehouse *Emit::warehouse(void) {
    return InterTree::warehouse(Emit::tree());
}

inter_bookmark *Emit::at?Usage of Emit::at:
§3, §4, §6, §7, §8, §9, §11, §12, §13, §14, §15, §16
Emit Arrays - §4, §10(void) {
    return Packaging::at(Emit::tree());
}

inter_ti Emit::baseline?Usage of Emit::baseline:
§4, §6, §7, §8, §11, §12, §13, §14, §15, §16
Emit Arrays - §10(void) {
    return Produce::baseline(Emit::at());
}

inter_package *Emit::package?Usage of Emit::package:
Emit Arrays - §10(void) {
    return InterBookmark::package(Emit::at());
}

package_request *Emit::current_enclosure?Usage of Emit::current_enclosure:
Enclosures - §1
Text Substitutions - §5
Literal Patterns - §7(void) {
    return Packaging::enclosure(Emit::tree());
}

packaging_state Emit::new_packaging_state?Usage of Emit::new_packaging_state:
Rulebooks - §8.4.1(void) {
    return Packaging::stateless();
}

§2. Data as pairs of Inter bytes. A single data value is stored in Inter bytecode as two consecutive words: see bytecode for more on this. This means we sometimes deal with a doublet of inter_ti variables:

void Emit::holster_iname?Usage of Emit::holster_iname:
Text Substitutions - §2.2
Box Quotations - §1(value_holster *VH, inter_name *iname) {
    if (Holsters::value_pair_allowed(VH)) {
        if (iname == NULL) internal_error("no iname to holster");
        Holsters::holster_pair(VH, Emit::to_value_pair(iname));
    }
}

§3. A subtlety here is that the encoding of a symbol into a doublet depends on what package it belongs to, the "context" referred to below:

inter_pair Emit::symbol_to_value_pair?Usage of Emit::symbol_to_value_pair:
§8
Emit Arrays - §4(inter_symbol *S) {
    return Emit::stvp_inner(S, InterBookmark::package(Emit::at()));
}

inter_pair Emit::to_value_pair?Usage of Emit::to_value_pair:
§2
Default Values - §2.1, §2.2, §2.4, §2.6, §2.7, §2.8, §3(inter_name *iname) {
    return Emit::stvp_inner(InterNames::to_symbol(iname), InterBookmark::package(Emit::at()));
}

inter_pair Emit::to_value_pair_in_context?Usage of Emit::to_value_pair_in_context:
§9(inter_name *context, inter_name *iname) {
    inter_package *pack = Packaging::incarnate(InterNames::location(context));
    inter_symbol *S = InterNames::to_symbol(iname);
    return Emit::stvp_inner(S, pack);
}

inter_pair Emit::stvp_inner(inter_symbol *S, inter_package *pack) {
    if (S) return InterValuePairs::symbolic_in(pack, S);
    return InterValuePairs::number(0);
}

§4. Kinds. Inter has a very simple, and non-binding, system of "typenames" — a much simpler system than Inform's hierarchy of kinds. Here we create a typename corresponding to each kind whose data we will need to use in Inter. super is the superkind, if any; constructor is one of the codes defined in Inter Data Types (in bytecode); the other three arguments are for kind constructors.

define MAX_KIND_ARITY 128

void Emit::kind?Usage of Emit::kind:
Kind Declarations - §8, §9(inter_name *iname, inter_name *super,
    inter_ti constructor, int arity, kind **operand_kinds) {
    packaging_state save = Packaging::enter_home_of(iname);
    inter_symbol *S = InterNames::to_symbol(iname);
    inter_symbol *SS = (super)?InterNames::to_symbol(super):NULL;
    inter_ti operands[MAX_KIND_ARITY];
    if (arity > MAX_KIND_ARITY) internal_error("kind arity too high");
    for (int i=0; i<arity; i++) {
        if ((operand_kinds[i] == K_nil) || (operand_kinds[i] == K_void)) operands[i] = 0;
        else operands[i] = Produce::kind_to_TID(Emit::at(), operand_kinds[i]);
    }
    Produce::guard(TypenameInstruction::new(Emit::at(), S, constructor, SS, arity,
        operands, Emit::baseline(), NULL));
    InterNames::to_symbol(iname);
    Packaging::exit(Emit::tree(), save);
}

§5. Pragmas. The Inter language allows pragmas, or code-generation hints, to be passed through. These are specific to the target of compilation, and can be ignored by all other targets.

void Emit::pragma?Usage of Emit::pragma:
Use Options - §1.4(text_stream *target, text_stream *text) {
    inter_tree *I = Emit::tree();
    LargeScale::emit_pragma(I, target, text);
    LOGIF(USE_OPTIONS, "Pragma set for target '%S': '%S'\n", target, text);
}

§6. Constants. These functions make it easy to define a named value in Inter. If the value is an unsigned numeric constant, use one of these two functions — the first if it represents an actual number at run-time, the second if not:

inter_name *Emit::numeric_constant?Usage of Emit::numeric_constant:
Hierarchy - §23
Compilation Units - §2.1.3
The Heap - §2
Completion Module - §1.5, §1.6, §1.7, §1.8, §1.13.1
Use Options - §1.3, §3
Responses - §6
Activities - §8
Chronology - §3.3, §7.1
Conjugations - §12
Tables - §2.1.1.1.3, §2.3
Table Columns - §2
Rules - §12.2
Rulebooks - §8.2
Variables - §14
Properties - §8.3
Relations - §5, §10.3
Kind Constructors - §32.1.1, §32.1.2, §32.3.1, §32.3.3, §32.3.4, §32.3.5
Kind IDs - §9.2
Actions - §8.1, §8.3
Bibliographic Data - §1.6
The Player - §1
The Map - §1
Command Grammars - §3, §11, §16(inter_name *con_iname, inter_ti val) {
    return Emit::numeric_constant_inner(con_iname,
        InterValuePairs::number_in_base(val, 10), INT32_ITCONC);
}

inter_name *Emit::named_numeric_constant_hex?Usage of Emit::named_numeric_constant_hex:
Relations - §1(inter_name *con_iname, inter_ti val) {
    return Emit::numeric_constant_inner(con_iname,
        InterValuePairs::number_in_base(val, 16), INT32_ITCONC);
}

inter_name *Emit::named_unchecked_constant_hex(inter_name *con_iname, inter_ti val) {
    return Emit::numeric_constant_inner(con_iname,
        InterValuePairs::number_in_base(val, 16), UNCHECKED_ITCONC);
}

inter_name *Emit::named_numeric_constant_signed?Usage of Emit::named_numeric_constant_signed:
Conjugations - §1(inter_name *con_iname, int val) {
    return Emit::numeric_constant_inner(con_iname,
        InterValuePairs::signed_number(val), INT32_ITCONC);
}

inter_name *Emit::unchecked_numeric_constant?Usage of Emit::unchecked_numeric_constant:
Actions - §8.2
Bibliographic Data - §1.3
Command Grammar Lines - §9(inter_name *con_iname, inter_ti val) {
    return Emit::numeric_constant_inner(con_iname,
        InterValuePairs::number_in_base(val, 10), UNCHECKED_ITCONC);
}

inter_name *Emit::numeric_constant_inner(inter_name *con_iname, inter_pair val,
    inter_ti constructor_code) {
    packaging_state save = Packaging::enter_home_of(con_iname);
    inter_symbol *con_s = InterNames::to_symbol(con_iname);
    Produce::guard(ConstantInstruction::new(Emit::at(), con_s,
        InterTypes::from_constructor_code(constructor_code), val,
        Emit::baseline(), NULL));
    Packaging::exit(Emit::tree(), save);
    return con_iname;
}

§7. Text:

void Emit::text_constant?Usage of Emit::text_constant:
§10
Hierarchy - §23
Completion Module - §1.1, §1.2, §1.3, §1.4, §1.9.1
Responses - §6
Rulebooks - §15.2
Bibliographic Data - §1.1, §1.2, §1.3, §1.4, §1.5, §1.6, §2(inter_name *con_iname, text_stream *contents) {
    packaging_state save = Packaging::enter_home_of(con_iname);
    inter_symbol *con_s = InterNames::to_symbol(con_iname);
    Produce::guard(ConstantInstruction::new(Emit::at(), con_s,
        InterTypes::from_constructor_code(TEXT_ITCONC),
        InterValuePairs::from_text(Emit::at(), contents), Emit::baseline(), NULL));
    Packaging::exit(Emit::tree(), save);
}

void Emit::text_constant_literal?Usage of Emit::text_constant_literal:
Text Literals - §4(inter_name *con_iname, text_stream *contents) {
    packaging_state save = Packaging::enter_home_of(con_iname);
    inter_symbol *con_s = InterNames::to_symbol(con_iname);
    Produce::guard(ConstantInstruction::new(Emit::at(), con_s,
        LargeScale::text_literal_type(Emit::tree()),
        InterValuePairs::from_text(Emit::at(), contents), Emit::baseline(), NULL));
    Packaging::exit(Emit::tree(), save);
}

§8. And equating one constant to another named constant:

inter_name *Emit::iname_constant?Usage of Emit::iname_constant:
Hierarchy - §23
Instance Counting - §8
Short Names - §2
Responses - §6
Activities - §8
Chronology - §4, §8
Conjugations - §12
Scene Instances - §3, §7
Tables - §2.1.1.1.3
Dialogue Beat Instances - §2
Rulebooks - §8.2, §8.4, §15.3
Properties - §8.2
Relations - §4, §5, §6.2
Kind IDs - §6, §9.2
Actions - §8.3, §8.4(inter_name *con_iname, kind *K, inter_name *val_iname) {
    packaging_state save = Packaging::enter_home_of(con_iname);
    inter_symbol *con_s = InterNames::to_symbol(con_iname);
    inter_symbol *val_s = (val_iname)?InterNames::to_symbol(val_iname):NULL;
    if (val_s == NULL) {
        if (Kinds::Behaviour::is_object(K))
            val_s = InterNames::to_symbol(Hierarchy::find(NOTHING_HL));
        else
            internal_error("can't handle a null alias");
    }
    Produce::guard(ConstantInstruction::new(Emit::at(), con_s,
        Produce::kind_to_type(K), Emit::symbol_to_value_pair(val_s),
        Emit::baseline(), NULL));
    Packaging::exit(Emit::tree(), save);
    return con_iname;
}

§9. These two variants are needed only for the oddball way Bibliographic Data is compiled.

void Emit::text_constant_from_wide_string?Usage of Emit::text_constant_from_wide_string:
Bibliographic Data - §1.1, §1.2(inter_name *con_iname, inchar32_t *str) {
    inter_name *iname = TextLiterals::to_value(Feeds::feed_C_string(str));
    Emit::named_generic_constant(con_iname,
        Emit::to_value_pair_in_context(con_iname, iname));
}

void Emit::serial_number?Usage of Emit::serial_number:
Bibliographic Data - §1.5(inter_name *con_iname, text_stream *serial) {
    packaging_state save = Packaging::enter_home_of(con_iname);
    inter_pair val = InterValuePairs::from_text(Emit::at(), serial);
    Emit::named_generic_constant(con_iname, val);
    Packaging::exit(Emit::tree(), save);
}

§10. Similarly, there are just a few occasions when we need to extract the value of a "variable" and define it as a constant:

void Emit::initial_value_as_constant?Usage of Emit::initial_value_as_constant:
Variables - §14
Bibliographic Data - §1.1, §1.2, §1.3, §1.4(inter_name *con_iname, nonlocal_variable *var) {
    Emit::named_generic_constant(con_iname,
        RTVariables::initial_value_as_pair(con_iname, var));
}

void Emit::initial_value_as_raw_text?Usage of Emit::initial_value_as_raw_text:
Bibliographic Data - §1.1, §1.2, §1.3, §1.6(inter_name *con_iname, nonlocal_variable *var) {
    wording W = NonlocalVariables::initial_value_as_plain_text(var);
    TEMPORARY_TEXT(CONTENT)
    BibliographicData::compile_bibliographic_text(CONTENT,
        Lexer::word_text(Wordings::first_wn(W)), XML_BIBTEXT_MODE);
    Emit::text_constant(con_iname, CONTENT);
    DISCARD_TEXT(CONTENT)
}

§11. The above make use of this:

void Emit::named_generic_constant?Usage of Emit::named_generic_constant:
§9, §10(inter_name *con_iname, inter_pair val) {
    packaging_state save = Packaging::enter_home_of(con_iname);
    inter_symbol *con_s = InterNames::to_symbol(con_iname);
    Produce::guard(ConstantInstruction::new(Emit::at(), con_s,
        InterTypes::unchecked(), val, Emit::baseline(), NULL));
    Packaging::exit(Emit::tree(), save);
}

§12. Instances.

void Emit::instance?Usage of Emit::instance:
Instances - §4(inter_name *inst_iname, kind *K, inter_ti v, int has_value) {
    packaging_state save = Packaging::enter_home_of(inst_iname);
    inter_symbol *inst_s = InterNames::to_symbol(inst_iname);
    inter_pair val = has_value ? InterValuePairs::number(v) : InterValuePairs::undef();
    Produce::guard(InstanceInstruction::new(Emit::at(), inst_s,
        Produce::kind_to_symbol(K), val, Emit::baseline(), NULL));
    Packaging::exit(Emit::tree(), save);
}

§13. Variables.

inter_symbol *Emit::variable?Usage of Emit::variable:
Variables - §14(inter_name *var_iname, kind *K, inter_pair val) {
    packaging_state save = Packaging::enter_home_of(var_iname);
    inter_symbol *var_s = InterNames::to_symbol(var_iname);
    inter_type type = InterTypes::unchecked();
    if ((K) && (K != K_value))
        type = InterTypes::from_type_name(Produce::kind_to_symbol(K));
    Produce::guard(VariableInstruction::new(Emit::at(), var_s, type, val,
        Emit::baseline(), NULL));
    Packaging::exit(Emit::tree(), save);
    return var_s;
}

§14. Properties and permissions.

void Emit::property?Usage of Emit::property:
Properties - §8.1(inter_name *prop_iname, kind *K) {
    packaging_state save = Packaging::enter_home_of(prop_iname);
    inter_symbol *prop_s = InterNames::to_symbol(prop_iname);
    inter_type type = InterTypes::unchecked();
    if ((K) && (K != K_value))
        type = InterTypes::from_type_name(Produce::kind_to_symbol(K));
    Produce::guard(PropertyInstruction::new(Emit::at(), prop_s, type, Emit::baseline(), NULL));
    Packaging::exit(Emit::tree(), save);
}

void Emit::permission?Usage of Emit::permission:
Property Permissions - §4(property *prn, inter_symbol *owner_s, inter_name *storage_iname) {
    inter_name *prop_iname = RTProperties::iname(prn);
    inter_symbol *store_s = (storage_iname)?InterNames::to_symbol(storage_iname):NULL;
    inter_symbol *prop_s = InterNames::to_symbol(prop_iname);
    Produce::guard(PermissionInstruction::new(Emit::at(), prop_s, owner_s, store_s,
        Emit::baseline(), NULL));
}

§15. Property values.

void Emit::propertyvalue?Usage of Emit::propertyvalue:
Property Values - §2.2.1(property *P, inter_name *owner, inter_pair val) {
    inter_symbol *prop_s = InterNames::to_symbol(RTProperties::iname(P));
    inter_symbol *owner_s = InterNames::to_symbol(owner);
    Produce::guard(PropertyValueInstruction::new(Emit::at(), prop_s, owner_s, val,
        Emit::baseline(), NULL));
}

§16. Interventions. These should be used as little as possible, and perhaps it may one day be possible to abolish them altogether. They insert direct kit material (i.e. paraphrased Inter code written out as plain text in Inform 6 notation) into bytecode; this is then assimilating during linking.

void Emit::intervention?Usage of Emit::intervention:
Interventions - §1(text_stream *raw_matter, text_stream *replacing) {
    filename *F = NULL;
    inter_ti lc = 0;
    if (current_sentence) {
        wording W = current_sentence->text_parsed;
        source_file *sf = Lexer::file_of_origin(Wordings::first_wn(W));
        if (sf) F = TextFromFiles::get_filename(sf);
        lc = (inter_ti) Lexer::line_of_origin(Wordings::first_wn(W));
    }
    Produce::guard(
        InsertInstruction::new(Emit::at(), raw_matter, replacing, F, lc,
        Emit::baseline(), NULL));
}

§17. And this is a similarly inelegant construction:

void Emit::append?Usage of Emit::append:
Interventions - §2(inter_name *iname, text_stream *text) {
    inter_symbol *symbol = InterNames::to_symbol(iname);
    SymbolAnnotation::set_t(InterPackage::tree(InterSymbol::package(symbol)),
        InterSymbol::package(symbol), symbol, APPEND_IANN, text);
}