Defining the typename construct.

• §1. Definition
• §2. Instructions
• §4. Creating from textual Inter syntax
• §5. Writing to textual Inter syntax
• §6. Access functions
• §10. Two tests

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

void TypenameInstruction::define_construct?Usage of TypenameInstruction::define_construct:
Inter Constructs - §15(void) {
    inter_construct *IC = InterInstruction::create_construct(TYPENAME_IST, I"typename");
    InterInstruction::defines_symbol_in_fields(IC, DEFN_TYPENAME_IFLD, -1);
    InterInstruction::specify_syntax(IC, I"typename IDENTIFIER TOKEN TOKENS");
    InterInstruction::data_extent_at_least(IC, 7);
    InterInstruction::permit(IC, INSIDE_PLAIN_PACKAGE_ICUP);
    METHOD_ADD(IC, CONSTRUCT_READ_MTID, TypenameInstruction::read);
    METHOD_ADD(IC, CONSTRUCT_TRANSPOSE_MTID, TypenameInstruction::transpose);
    METHOD_ADD(IC, CONSTRUCT_VERIFY_MTID, TypenameInstruction::verify);
    METHOD_ADD(IC, CONSTRUCT_WRITE_MTID, TypenameInstruction::write);
}

§2. Instructions. In bytecode, the frame of a typename instruction is laid out with the compulsory words — see Inter Nodes — followed by these. The eventual length is flexible: there can be any number of operands from 0 upwards.

define DEFN_TYPENAME_IFLD         (DATA_IFLD + 0)
define ENUM_RANGE_TYPENAME_IFLD   (DATA_IFLD + 1)
define NO_INSTANCES_TYPENAME_IFLD (DATA_IFLD + 2)
define SUPER_TYPENAME_IFLD        (DATA_IFLD + 3)
define PERM_LIST_TYPENAME_IFLD    (DATA_IFLD + 4)
define PLIST_TYPENAME_IFLD        (DATA_IFLD + 5)
define CONSTRUCTOR_TYPENAME_IFLD  (DATA_IFLD + 6)
define OPERANDS_TYPENAME_IFLD     (DATA_IFLD + 7)

inter_error_message *TypenameInstruction::new?Usage of TypenameInstruction::new:
§4(inter_bookmark *IBM, inter_symbol *typename_s,
    inter_ti constructor, inter_symbol *super_s,
    int arity, inter_ti *operands, inter_ti level, inter_error_location *eloc) {
    inter_ti super_SID = 0;
    if (super_s) super_SID = InterSymbolsTable::id_at_bookmark(IBM, super_s);
    inter_package *pack = InterBookmark::package(IBM);
    inter_warehouse *warehouse = InterBookmark::warehouse(IBM);
    inter_tree_node *P = Inode::new_with_7_data_fields(IBM, TYPENAME_IST,
        /* DEFN_TYPENAME_IFLD: */         InterSymbolsTable::id_at_bookmark(IBM, typename_s),
        /* ENUM_RANGE_TYPENAME_IFLD: */   0,
        /* NO_INSTANCES_TYPENAME_IFLD: */ 0,
        /* SUPER_TYPENAME_IFLD: */        super_SID,
        /* PERM_LIST_TYPENAME_IFLD: */    InterWarehouse::create_node_list(warehouse, pack),
        /* PLIST_TYPENAME_IFLD: */        InterWarehouse::create_node_list(warehouse, pack),
        /* CONSTRUCTOR_TYPENAME_IFLD: */  constructor,
        eloc, level);
    if (arity > 0) {
        Inode::extend_instruction_by(P, (inter_ti) arity);
        for (int i=0; i<arity; i++)
            P->W.instruction[OPERANDS_TYPENAME_IFLD+i] = operands[i];
    }
    inter_error_message *E = VerifyingInter::instruction(InterBookmark::package(IBM), P);
    if (E) return E;
    NodePlacement::move_to_moving_bookmark(P, IBM);
    return NULL;
}

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

§3. Verification consists only of sanity checks.

void TypenameInstruction::verify?Usage of TypenameInstruction::verify:
§1(inter_construct *IC, inter_tree_node *P,
    inter_package *owner, inter_error_message **E) {
    inter_symbol *typename_s = TypenameInstruction::typename(P);
    if ((P->W.instruction[ENUM_RANGE_TYPENAME_IFLD] > 0) &&
        (InterTypes::is_enumerated(InterTypes::from_type_name(typename_s)) == FALSE)) {
        *E = Inode::error(P, I"spurious extent in non-enumeration", NULL);
        return;
    }
    if (P->W.instruction[SUPER_TYPENAME_IFLD] != 0) {
        *E = VerifyingInter::SID_field(owner, P, SUPER_TYPENAME_IFLD, TYPENAME_IST);
        if (*E) return;
        inter_symbol *super_s = TypenameInstruction::super(typename_s);
        if (InterTypes::is_enumerated(InterTypes::from_type_name(super_s)) == FALSE) {
            *E = Inode::error(P, I"subtype of nonenumerated type", NULL);
            return;
        }
    }
    *E = VerifyingInter::node_list_field(owner, P, PERM_LIST_TYPENAME_IFLD);
    if (*E) return;
    *E = VerifyingInter::node_list_field(owner, P, PLIST_TYPENAME_IFLD);
    if (*E) return;
    *E = VerifyingInter::constructor_field(P, CONSTRUCTOR_TYPENAME_IFLD);
    if (*E) return;
    inter_type type =
        InterTypes::from_constructor_code(TypenameInstruction::constructor(typename_s));
    int arity = P->W.extent - OPERANDS_TYPENAME_IFLD;
    for (int i=0; i<arity; i++) {
        *E = VerifyingInter::TID_field(owner, P, OPERANDS_TYPENAME_IFLD + i);
        if (*E) return;
    }
    if (InterTypes::arity_is_possible(type, arity) == FALSE) {
        text_stream *err = Str::new();
        WRITE_TO(err, "typename definition has arity %d, which is impossible for ", arity);
        InterTypes::write_type(err, type);
        *E = Inode::error(P, err, NULL);
        return;
    }
}

§4. Creating from textual Inter syntax.

void TypenameInstruction::read?Usage of TypenameInstruction::read:
§1(inter_construct *IC, inter_bookmark *IBM,
    inter_line_parse *ilp, inter_error_location *eloc, inter_error_message **E) {
    text_stream *typename_text = ilp->mr.exp[0];
    text_stream *operator_text = ilp->mr.exp[1];
    text_stream *defn_text = ilp->mr.exp[2];
    inter_symbol *symb =
        TextualInter::new_symbol(eloc, InterBookmark::scope(IBM), typename_text, E);
    if (*E) return;

    inter_semisimple_type_description parsed_description;
    InterTypes::initialise_isstd(&parsed_description);
    inter_symbol *super_s = NULL;

    if (Str::eq(operator_text, I"<=")) {
        super_s = TextualInter::find_symbol(IBM, eloc, defn_text, TYPENAME_IST, E);
        if ((*E == NULL) &&
            (InterTypes::is_enumerated(InterTypes::from_type_name(super_s)) == FALSE)) {
                *E = InterErrors::quoted(I"not a type which can have subtypes", defn_text, eloc);
                return;
        }
        parsed_description.constructor_code = ENUM_ITCONC;
        parsed_description.arity = 0;
    } else if (Str::eq(operator_text, I"=")) {
        *E = InterTypes::parse_semisimple(ilp->mr.exp[2], InterBookmark::scope(IBM),
            eloc, &parsed_description);
    } else {
        *E = InterErrors::quoted(I"expected '=' or '<='", operator_text, eloc);
    }

    if (*E == NULL)
        *E = TypenameInstruction::new(IBM, symb, parsed_description.constructor_code,
            super_s, parsed_description.arity, parsed_description.operand_TIDs,
            (inter_ti) ilp->indent_level, eloc);
    InterTypes::dispose_of_isstd(&parsed_description);
}

§5. Writing to textual Inter syntax.

void TypenameInstruction::write?Usage of TypenameInstruction::write:
§1(inter_construct *IC, OUTPUT_STREAM, inter_tree_node *P) {
    inter_symbol *typename_s = TypenameInstruction::typename(P);
    WRITE("typename %S ", InterSymbol::identifier(typename_s));
    inter_symbol *super = TypenameInstruction::super(typename_s);
    if (super) {
        WRITE("<= ");
        TextualInter::write_symbol_from(OUT, P, SUPER_TYPENAME_IFLD);
    } else {
        WRITE("= ");
        InterTypes::write_typename_definition(OUT, typename_s);
    }
}

§6. Access functions.

inter_symbol *TypenameInstruction::typename?Usage of TypenameInstruction::typename:
§3, §5(inter_tree_node *P) {
    if (P == NULL) return NULL;
    if (Inode::isnt(P, TYPENAME_IST)) return NULL;
    return InterSymbolsTable::symbol_from_ID_at_node(P, DEFN_TYPENAME_IFLD);
}

inter_symbol *TypenameInstruction::super?Usage of TypenameInstruction::super:
§3, §5, §9, §10
The PropertyValue Construct - §3(inter_symbol *typename_s) {
    if (typename_s == NULL) return NULL;
    inter_tree_node *D = InterSymbol::definition(typename_s);
    if (D == NULL) return NULL;
    return InterSymbolsTable::symbol_from_ID_at_node(D, SUPER_TYPENAME_IFLD);
}

inter_node_list *TypenameInstruction::permissions_list?Usage of TypenameInstruction::permissions_list:
The Permission Construct - §3
The PropertyValue Construct - §3(inter_symbol *typename_s) {
    if (typename_s == NULL) return NULL;
    inter_tree_node *D = InterSymbol::definition(typename_s);
    if (D == NULL) return NULL;
    return Inode::ID_to_frame_list(D, D->W.instruction[PERM_LIST_TYPENAME_IFLD]);
}

inter_node_list *TypenameInstruction::properties_list?Usage of TypenameInstruction::properties_list:
The PropertyValue Construct - §3(inter_symbol *typename_s) {
    if (typename_s == NULL) return NULL;
    inter_tree_node *D = InterSymbol::definition(typename_s);
    if (D == NULL) return NULL;
    return Inode::ID_to_frame_list(D, D->W.instruction[PLIST_TYPENAME_IFLD]);
}

§7. The definition of the semisimple type:

inter_ti TypenameInstruction::constructor?Usage of TypenameInstruction::constructor:
§3
Inter Data Types - §10(inter_symbol *typename_s) {
    if (typename_s == NULL) return UNCHECKED_ITCONC;
    inter_tree_node *D = InterSymbol::definition(typename_s);
    if (D == NULL) return UNCHECKED_ITCONC;
    return D->W.instruction[CONSTRUCTOR_TYPENAME_IFLD];
}

int TypenameInstruction::arity?Usage of TypenameInstruction::arity:
Inter Data Types - §13(inter_symbol *typename_s) {
    if (typename_s == NULL) return 0;
    inter_tree_node *D = InterSymbol::definition(typename_s);
    if (D == NULL) return 0;
    return D->W.extent - OPERANDS_TYPENAME_IFLD;
}

inter_type TypenameInstruction::operand_type?Usage of TypenameInstruction::operand_type:
Inter Data Types - §13(inter_symbol *typename_s, int i) {
    if (typename_s == NULL) return InterTypes::unchecked();
    inter_tree_node *D = InterSymbol::definition(typename_s);
    if (D == NULL) return InterTypes::unchecked();
    if (i >= D->W.extent - OPERANDS_TYPENAME_IFLD) return InterTypes::unchecked();
    inter_ti TID = D->W.instruction[OPERANDS_TYPENAME_IFLD + i];
    inter_symbols_table *T = InterPackage::scope_of(D);
    return InterTypes::from_TID(T, TID);
}

§8. Enumeration counter, relevant only when the typename is enumerated:

inter_ti TypenameInstruction::next_enumerated_value?Usage of TypenameInstruction::next_enumerated_value:
The Instance Construct - §3(inter_symbol *typename_s) {
    if (typename_s == NULL) return 0;
    inter_tree_node *D = InterSymbol::definition(typename_s);
    if (D == NULL) return 0;
    return ++(D->W.instruction[ENUM_RANGE_TYPENAME_IFLD]);
}

§9. For an enumerated typename, if a new instance is created, this is called:

void TypenameInstruction::new_instance?Usage of TypenameInstruction::new_instance:
The Instance Construct - §3(inter_symbol *typename_s, inter_symbol *inst_name) {
    if (typename_s == NULL) return;
    inter_tree_node *D = InterSymbol::definition(typename_s);
    if (D == NULL) return;
    D->W.instruction[NO_INSTANCES_TYPENAME_IFLD]++;
    inter_symbol *S = TypenameInstruction::super(typename_s);
    if (S) TypenameInstruction::new_instance(S, inst_name);
}

int TypenameInstruction::instance_count(inter_symbol *typename_s) {
    if (typename_s == NULL) return 0;
    inter_tree_node *D = InterSymbol::definition(typename_s);
    if (D == NULL) return 0;
    return (int) D->W.instruction[NO_INSTANCES_TYPENAME_IFLD];
}

§10. Two tests.

int TypenameInstruction::is?Usage of TypenameInstruction::is:
The Permission Construct - §3
The PropertyValue Construct - §3(inter_symbol *typename_s) {
    if (typename_s == NULL) return FALSE;
    inter_tree_node *D = InterSymbol::definition(typename_s);
    if (Inode::is(D, TYPENAME_IST)) return TRUE;
    return FALSE;
}

int TypenameInstruction::is_a?Usage of TypenameInstruction::is_a:
Inter Data Types - §22.2(inter_symbol *typename1_s, inter_symbol *typename2_s) {
    inter_type type1 = InterTypes::from_type_name(typename1_s);
    inter_type type2 = InterTypes::from_type_name(typename2_s);
    if ((InterTypes::is_unchecked(type1)) || (InterTypes::is_unchecked(type2)))
        return TRUE;
    while (typename1_s) {
        if (typename1_s == typename2_s) return TRUE;
        typename1_s = TypenameInstruction::super(typename1_s);
    }
    return FALSE;
}