Adjective Meanings

One individual meaning which an adjective can have.

§1. Meanings. For example, "odd" in the sense of numbers is a single meaning. Each meaning is an instance of:

typedef struct adjective_meaning {
    struct adjective *owning_adjective;  of which this is a meaning

    struct adjective_domain_data domain;  to what can this meaning be applied?

    struct adjective_meaning_family *family;
    general_pointer family_specific_data;  to the relevant structure
    struct adjective_meaning *negated_from;  if explicitly constructed as such

    struct wording indexing_text;  text to use in the Phrasebook index
    struct parse_node *defined_at;  from what sentence this came (if it did)

    int schemas_prepared;  have schemas been prepared yet?
    struct adjective_task_data task_data[NO_ATOM_TASKS + 1];  see below

    int has_been_compiled_in_support_function;  which may never happen

    CLASS_DEFINITION
} adjective_meaning;

The structure adjective_meaning is accessed in 3/nrr, 5/id, 5/idf, 5/adf, 5/tpf, 5/rf, 8/tap, 8/tcp, 8/aa, 8/amd, 8/abp, 8/abif and here.

§2. This can be created in two ways: straightforwardly —

adjective_meaning *AdjectiveMeanings::new(adjective_meaning_family *family,
    general_pointer details, wording W) {
    adjective_meaning *am = CREATE(adjective_meaning);
    am->defined_at = current_sentence;
    am->indexing_text = W;
    am->owning_adjective = NULL;
    am->domain = AdjectiveMeaningDomains::new_from_text(EMPTY_WORDING);
    am->family = family;
    am->family_specific_data = details;
    am->has_been_compiled_in_support_function = FALSE;
    am->schemas_prepared = FALSE;
    am->negated_from = NULL;
    AdjectiveMeanings::initialise_all_task_data(am);
    return am;
}

§3. Or as the logical negation of an existing meaning (thus, "odd" for numbers might be created as the negation of "even" for numbers):

adjective_meaning *AdjectiveMeanings::negate(adjective_meaning *other) {
    if (other->negated_from) internal_error("cannot negate an already negated AM");
    adjective_meaning *am = CREATE(adjective_meaning);
    am->defined_at = current_sentence;
    am->indexing_text = other->indexing_text;
    am->owning_adjective = NULL;
    am->domain = other->domain;
    am->family = other->family;
    am->family_specific_data = other->family_specific_data;
    am->has_been_compiled_in_support_function = FALSE;
    am->schemas_prepared = FALSE;
    am->negated_from = other;
    AdjectiveMeanings::negate_task_data(am, other);
    for (int i=1; i<=NO_ATOM_TASKS; i++) {
        int j = i;
        if (i == NOW_ATOM_TRUE_TASK) j = NOW_ATOM_FALSE_TASK;
        if (i == NOW_ATOM_FALSE_TASK) j = NOW_ATOM_TRUE_TASK;
        AdjectiveMeanings::copy_task_data(&(am->task_data[j]), &(other->task_data[i]));
        Calculus::Schemas::modify(&(am->task_data[j].call_to_support_function), "");
    }
    return am;
}

§4. Task data. When Inform needs to compile code for testing if an adjective is true as applied to something, or to make it now true (or false), it does this by compiling code for the associated unary predicate — see The Adjectival Predicates. What to compile depends on the meaning or meanings which might apply; if it's this meaning, then we will need an I6 schema to carry out one of three tasks, TEST_ATOM_TASK, NOW_ATOM_TRUE_TASK, or NOW_ATOM_FALSE_TASK.

A meaning has one of these for each of the possible tasks:

typedef struct adjective_task_data {
    int task_mode;  one of the *_TASKMODE constants: see below
    struct i6_schema call_to_support_function;  where TRUE
    struct i6_schema code_to_perform;  where TRUE
} adjective_task_data;

void AdjectiveMeanings::initialise_task_data(adjective_task_data *atd) {
    atd->task_mode = NO_TASKMODE;
    Calculus::Schemas::modify(&(atd->code_to_perform), "");
    Calculus::Schemas::modify(&(atd->call_to_support_function), "");
}

void AdjectiveMeanings::copy_task_data(adjective_task_data *to, adjective_task_data *from) {
    to->task_mode = from->task_mode;
    to->code_to_perform = from->code_to_perform;
    to->call_to_support_function = from->call_to_support_function;
}

The structure adjective_task_data is private to this section.

§5. These functions set up the task data for a new meaning. Note the transposition, so that a negated meaning has the NOW_ATOM_TRUE_TASK and NOW_ATOM_FALSE_TASK switched around from the original.

void AdjectiveMeanings::initialise_all_task_data(adjective_meaning *am) {
    for (int i=1; i<=NO_ATOM_TASKS; i++)
        AdjectiveMeanings::initialise_task_data(&(am->task_data[i]));
}

void AdjectiveMeanings::negate_task_data(adjective_meaning *am, adjective_meaning *other) {
    for (int i=1; i<=NO_ATOM_TASKS; i++) {
        int j = i;
        if (i == NOW_ATOM_TRUE_TASK) j = NOW_ATOM_FALSE_TASK;
        if (i == NOW_ATOM_FALSE_TASK) j = NOW_ATOM_TRUE_TASK;
        AdjectiveMeanings::copy_task_data(&(am->task_data[j]), &(other->task_data[i]));
        Calculus::Schemas::modify(&(am->task_data[j].call_to_support_function), "");
    }
}

§6. The schema for a task generates code to perform it. There are three strategies:

● produce a problem message, saying this is impossible;
● compile direct inline code;
● compile a function call to a function, which actually performs the task;

Those strategies correspond to the three *_TASKMODE constants.

By default, an adjective meaning is unable to perform any of the three tasks, and the creator of it has to call AdjectiveMeanings::make_schema to say otherwise. This puts us by default into DIRECT_TASKMODE, unless we're working in the world of objects where run-time typechecking will be needed — in which case VIA_SUPPORT_FUNCTION_TASKMODE. But the creator can insist on the latter anyway with a subsequent call to AdjectiveMeanings::perform_task_via_function.

enum NO_TASKMODE from 1
enum DIRECT_TASKMODE
enum VIA_SUPPORT_FUNCTION_TASKMODE

i6_schema *AdjectiveMeanings::make_schema(adjective_meaning *am, int T) {
    kind *K = AdjectiveMeaningDomains::get_kind(am);
    if (K == NULL) K = K_object;
    int via_support = DIRECT_TASKMODE;
    if (Kinds::Behaviour::is_object(K)) via_support = VIA_SUPPORT_FUNCTION_TASKMODE;
    am->task_data[T].task_mode = via_support;
    return &(am->task_data[T].code_to_perform);
}

void AdjectiveMeanings::perform_task_via_function(adjective_meaning *am, int T) {
    am->task_data[T].task_mode = VIA_SUPPORT_FUNCTION_TASKMODE;
}

§7. And this function reads it back, automatically generating the function call schema if it's needed.

i6_schema *AdjectiveMeanings::get_schema(adjective_meaning *am, int T) {
    AdjectiveMeanings::prepare_schemas(am, T);
    switch (am->task_data[T].task_mode) {
        case DIRECT_TASKMODE:
            return &(am->task_data[T].code_to_perform);
        case VIA_SUPPORT_FUNCTION_TASKMODE:
            if (Calculus::Schemas::empty(&(am->task_data[T].call_to_support_function)))
                Construct a schema for calling the support function7.1;
            return &(am->task_data[T].call_to_support_function);
    }
    return NULL;
}

i6_schema *AdjectiveMeanings::get_schema_without_call(adjective_meaning *am, int T) {
    AdjectiveMeanings::prepare_schemas(am, T);
    switch (am->task_data[T].task_mode) {
        case DIRECT_TASKMODE:
        case VIA_SUPPORT_FUNCTION_TASKMODE:
            return &(am->task_data[T].code_to_perform);
    }
    return NULL;
}

§7.1. Where the following is complicated by the need to respect negations; it may be that the original adjective has a support routine defined, but that the negation does not, and so must use those of the original.

Construct a schema for calling the support function7.1 =

    int task = T; char *negation_operator = "";
    adjective *use_adj = am->owning_adjective;
    if (am->negated_from) {
        use_adj = am->negated_from->owning_adjective;
        switch (T) {
            case TEST_ATOM_TASK: negation_operator = "~~"; break;
            case NOW_ATOM_TRUE_TASK: task = NOW_ATOM_FALSE_TASK; break;
            case NOW_ATOM_FALSE_TASK: task = NOW_ATOM_TRUE_TASK; break;
        }
    }
    inter_name *iname = RTAdjectives::task_fn_iname(use_adj, task,
        AdjectiveMeaningDomains::get_kind(am));
    Calculus::Schemas::modify(&(am->task_data[T].call_to_support_function),
        "*=-(%s%n(*1))", negation_operator, iname);

This code is used in §7.

§8. Families of adjective meanings. The above API would allow us to make fairly arbitrary one-off adjectives, but in practice we have a number of distinct purposes and want to make a whole pile of related adjectives for each one. So we actually create adjective meanings in "families".

Each family is represented by an instance of the following:

typedef struct adjective_meaning_family {
    struct method_set *methods;
    int definition_claim_priority;  0 to 9: lower is better
    CLASS_DEFINITION
} adjective_meaning_family;

adjective_meaning_family *AdjectiveMeanings::new_family(int N) {
    adjective_meaning_family *f = CREATE(adjective_meaning_family);
    f->definition_claim_priority = N;
    f->methods = Methods::new_set();
    return f;
}

The structure adjective_meaning_family is accessed in 5/idf and here.

§9. Families provide a number of methods to tweak how adjectives behave, and here goes. All of these methods are optional.

CLAIM_DEFINITION_SENTENCE_ADJM_MTID is an opportunity to say that a definition in the source text is asking for this kind of adjective. Suppose the source has a line like so:

Definition: A ... (called ...) is ... if ...

In place of the ellipses are respectively DNW (domain wording), CALLW (the calling), AW (the adjective) and CONW (the condition). sense is either 1, meaning that "if" was used (the condition has positive sense); or -1, meaning that it was "unless" (a negative sense); or 0, meaning that instead of a condition, a rule was supplied.

If the method is provided, it should look at these and decide if this is the sort of adjective it wants to make. If so, it should return TRUE and copy a pointer to the new adjective meaning into result. If not, it should return FALSE.

Of course, only one family can take the prize, and so the sequence in which the families are offered the chance to claim is significant. This sequence is ascending order of the family's definition_claim_priority field.

enum CLAIM_DEFINITION_SENTENCE_ADJM_MTID

INT_METHOD_TYPE(CLAIM_DEFINITION_SENTENCE_ADJM_MTID, adjective_meaning_family *f,
    adjective_meaning **result, parse_node *q, int sense,
    wording AW, wording DNW, wording CONW, wording CALLW)

adjective_meaning *AdjectiveMeanings::claim_definition(parse_node *q,
    int sense, wording AW, wording DNW, wording CONW, wording CALLW) {
    for (int priority = 0; priority < 10; priority++) {
        adjective_meaning_family *f;
        LOOP_OVER(f, adjective_meaning_family)
            if (f->definition_claim_priority == priority)
                Try the f family9.1;
    }
    return NULL;
}

§9.1. Try the f family9.1 =

    adjective_meaning *am = NULL;
    int rv = FALSE;
    INT_METHOD_CALL(rv, f, CLAIM_DEFINITION_SENTENCE_ADJM_MTID, &am, q, sense,
        AW, DNW, CONW, CALLW);
    if (rv) return am;

This code is used in §9.

§10. By default, an adjective meaning cannot be asserted, that is, said to be true of something (an inference subject) in the model world. So if "fizzy" is a newly created adjective, the sentence "The drink is fizzy" would be rejected. But if the family for "fizzy" provides an ASSERT_ADJM_MTID method, it's a different matter. The method should either return FALSE to decline after all, or draw some inferences and then return TRUE.

parity is TRUE if the assertion claims the meaning am is true about the subject subj, and otherwise FALSE.

enum ASSERT_ADJM_MTID

INT_METHOD_TYPE(ASSERT_ADJM_MTID, adjective_meaning_family *f, adjective_meaning *am,
    inference_subject *subj, int parity)

int AdjectiveMeanings::assert(adjective_meaning *am, inference_subject *subj,
    int parity) {
    if (am->negated_from) {
        am = am->negated_from; parity = (parity)?FALSE:TRUE;
    }
    int rv = FALSE;
    INT_METHOD_CALL(rv, am->family, ASSERT_ADJM_MTID, am, subj, parity);
    return rv;
}

§11. Next, PREPARE_SCHEMAS_ADJM_MTID. Just before code is about to be generated for the adjective to perform some task, this method is called. The idea is that this is an opportunity to compile a schema for the adjective at the last minute (as an alternative to having set the schemas up at creation time), but there is no obligation.

enum PREPARE_SCHEMAS_ADJM_MTID

VOID_METHOD_TYPE(PREPARE_SCHEMAS_ADJM_MTID, adjective_meaning_family *f,
    adjective_meaning *am, int task)

void AdjectiveMeanings::prepare_schemas(adjective_meaning *am, int task) {
    VOID_METHOD_CALL(am->family, PREPARE_SCHEMAS_ADJM_MTID, am, task);
    am->schemas_prepared = TRUE;
}

§12. GENERATE_IN_SUPPORT_FUNCTION_ADJM_MTID offers a way to bypass the usual code generation process. It is called on only when Adjectives (in runtime) is compiling a support function — and therefore it will never be called on if the adjective doesn't perform this task with a support function; see above.

It is called twice, first with emit_flag set to FALSE; it should do nothing, but return TRUE to indicate that it wants to generate wacky code of its own. On the second call, emit_flag will be TRUE, and this time the method should follow through on its earlier promise.

If the method is not provided or returns FALSE, then the code will be generated from the schema in the normal way.

As with schemas, T is the task to be performed.

If emit_flag is TRUE, then code should actually be generated, and within the given stack frame. If it is FALSE, the function should simply return whether it is able to do this or not.

enum GENERATE_IN_SUPPORT_FUNCTION_ADJM_MTID

INT_METHOD_TYPE(GENERATE_IN_SUPPORT_FUNCTION_ADJM_MTID, adjective_meaning_family *f,
    adjective_meaning *am, int T, int emit_flag, stack_frame *phsf)

§13. This dual behaviour means there are two function calls invoking it:

int AdjectiveMeanings::generate_in_support_function(adjective_meaning *am,
    int T, stack_frame *phsf) {
    int rv = AdjectiveMeanings::nscg_inner(am, T, TRUE, phsf);
    am->has_been_compiled_in_support_function = TRUE;
    return rv;
}

int AdjectiveMeanings::can_generate_in_support_function(adjective_meaning *am, int T) {
    return AdjectiveMeanings::nscg_inner(am, T, FALSE, NULL);
}

int AdjectiveMeanings::nscg_inner(adjective_meaning *am, int T, int emit_flag,
    stack_frame *phsf) {
    AdjectiveMeanings::prepare_schemas(am, T);
    Use the I6 schema instead to compile the task, if one exists13.1;
    int rv = FALSE;
    INT_METHOD_CALL(rv, am->family, GENERATE_IN_SUPPORT_FUNCTION_ADJM_MTID, am, T,
        emit_flag, phsf);
    return rv;
}

§13.1. Because we are inside the support function, we need to call AdjectiveMeanings::get_schema_without_call not AdjectiveMeanings::get_schema — otherwise, we would be given the schema for a function call to the very thing we are now trying to compile, and the result would be code which recursed forever.

The stack frame for the support function has a single variable "it" as number 0, and we set *1 to be this parameter. This is in fact the term we are performing the task on. *2 is unset.

Use the I6 schema instead to compile the task, if one exists13.1 =

    i6_schema *sch = AdjectiveMeanings::get_schema_without_call(am, T);
    if (Calculus::Schemas::empty(sch) == FALSE) {
        if (emit_flag) {
            parse_node *it_var = Lvalues::new_LOCAL_VARIABLE(EMPTY_WORDING,
                LocalVariables::it_variable());
            pcalc_term it_term = Terms::new_constant(it_var);
            CompileSchemas::from_terms_in_val_context(sch, &it_term, NULL);
        }
        return TRUE;
    }

This code is used in §13.

§14. At last, something simpler. INDEX_ADJM_MTID, if provided, should print a description suitable for use in the lexicon part of the index, and return TRUE. If not provided, or it returns FALSE, something sensible is done instead; this is only an opportunity to improve the wording.

Note that this is only called for the positive sense of an adjective meaning, not for one which is the negated form of another.

enum INDEX_ADJM_MTID

INT_METHOD_TYPE(INDEX_ADJM_MTID, adjective_meaning_family *f, text_stream *OUT,
    adjective_meaning *am)

int AdjectiveMeanings::nonstandard_index_entry(OUTPUT_STREAM, adjective_meaning *am) {
    int rv = FALSE;
    INT_METHOD_CALL(rv, am->family, INDEX_ADJM_MTID, OUT, am);
    return rv;
}