A feature to support the score variables.

§1. At one time, all interactive fiction had a scoring system, because that's what computers did for our entertainment: they rewarded us with points. Having its distant roots in that period, Inform handles a numerical score with just a little compiler support, and this is where.

void TheScore::start?Usage of TheScore::start:
IF Module - §5(void) {
    PluginCalls::plug(PRODUCTION_LINE_PLUG, TheScore::production_line);
    PluginCalls::plug(NEW_VARIABLE_NOTIFY_PLUG, TheScore::new_variable_notify);
}

int TheScore::production_line(int stage, int debugging, stopwatch_timer *sequence_timer) {
    if (stage == MODEL_CSEQ) {
        BENCH(TheScore::max_score_and_ranking_table);
    }
    return FALSE;
}

§2. For many years "maximum score" was compiled to a constant, but then people sent in bug reports asking why it wouldn't change in play. "Score", of course, is more evidently variable.

nonlocal_variable *score_VAR = NULL;
nonlocal_variable *max_score_VAR = NULL;

§3.

<notable-scoring-variables> ::=
    score |
    maximum score

• This is Preform grammar, not regular C code.

§4. These are marked "initialisable" because of the way they are implemented at run-time, using special variables in WorldModelKit rather than being storage allocated by I7. Variables stored that way would not ordinarily be possible to give values to in I7 assertions; but these are.

int TheScore::new_variable_notify?Usage of TheScore::new_variable_notify:
§1(nonlocal_variable *var) {
    if (<notable-scoring-variables>(var->name)) {
        switch(<<r>>) {
            case 0:
                score_VAR = var;
                RTVariables::make_initialisable(score_VAR);
                break;
            case 1:
                max_score_VAR = var;
                RTVariables::make_initialisable(max_score_VAR);
                break;
        }
    }
    return FALSE;
}

§5. A special rule is that if a table is called "Rankings" and contains a column of numbers followed by a column of text, then it is used by the run-time scoring system. In retrospect, Inform really shouldn't support this at the compiler level (not that it does much), but it does little harm.

<rankings-table-name> ::=
    rankings

• This is Preform grammar, not regular C code.

§6. Nothing will happen unless a table has both this magic name, and also the right shape: two columns, number then text. If so, the maximum score is initialised to the number in the final row of the table, which is assumed to be the score corresponding to successful completion and the highest rank.

The test case Cooking, an example from the documentation, tests this.

table *the_ranking_table = NULL;

void TheScore::max_score_and_ranking_table?Usage of TheScore::max_score_and_ranking_table:
§1(void) {
    table *t = NULL;
    LOOP_OVER(t, table)
        if ((<rankings-table-name>(t->table_name_text)) &&
            (Tables::get_no_columns(t) >= 2) &&
            (Kinds::eq(Tables::kind_of_ith_column(t, 0), K_number)) &&
            (Kinds::eq(Tables::kind_of_ith_column(t, 1), K_text)))
            the_ranking_table = t;
    if (the_ranking_table) {
        global_compilation_settings.ranking_table_given = TRUE;
        parse_node *PN = Tables::cells_in_ith_column(the_ranking_table, 0);
        while ((PN != NULL) && (PN->next != NULL)) PN = PN->next;
        if ((PN != NULL) && (max_score_VAR) &&
            (VariableSubjects::has_initial_value_set(max_score_VAR) == FALSE))
            Assertions::PropertyKnowledge::initialise_global_variable(
                max_score_VAR, Node::get_evaluation(PN));
    }
}

table *TheScore::ranking_table(void) {
    return the_ranking_table;
}