Turning a file of natural language into a syntax tree.

§1. Everything is now set up to read in a text file, break it into sentences, and then hand each one to linguistics in turn to construct syntax diagrams.

We need to tell linguistics which parts of a verb we will allow in these sentences — the answer being, all of them. (Inform is more restrictive.)

define ALLOW_VERB_IN_ASSERTIONS_LINGUISTICS_CALLBACK Diagramming::allow_in_assertions

int Diagramming::allow_in_assertions(verb_conjugation *vc, int tense, int sense, int person) {
    return TRUE;
}

§2. And so here goes.

parse_node_tree *syntax_tree = NULL;
parse_node_tree *Diagramming::test_diagrams?Usage of Diagramming::test_diagrams:
Program Control - §3(text_stream *arg, int raw) {
    syntax_tree = SyntaxTree::new();
    Turn the file into a syntax tree2.1;
    Use the linguistics module on each sentence2.2;
    return syntax_tree;
}

§2.1. Turn the file into a syntax tree2.1 =

    filename *F = Filenames::from_text(arg);
    feed_t FD = Feeds::begin();
    source_file *sf = TextFromFiles::feed_into_lexer(F, NULL_GENERAL_POINTER);
    wording W = Feeds::end(FD);
    if (sf == NULL) { PRINT("File has failed to open\n"); return NULL; }
    Sentences::break(syntax_tree, W);

• This code is used in §2.

§2.2. Use the linguistics module on each sentence2.2 =

    SyntaxTree::traverse(syntax_tree, Diagramming::diagram);
    if (raw == FALSE) Diagramming::parse_noun_phrases(syntax_tree->root_node);

• This code is used in §2.

§3. The work of the words and syntax modules means that we now have a rudimentary syntax tree, in which each sentence is just a single SENTENCE_NT node without children. We look for these, and apply <sentence>, the most powerful nonterminal from the linguistics module, to them. All being well (i.e., if any sentence structure can be found), this returns a subtree of further nodes, which we graft below the SENTENCE_NT.

void Diagramming::diagram?Usage of Diagramming::diagram:
§2.2(parse_node *p) {
    if (Node::get_type(p) == SENTENCE_NT) {
        wording W = Node::get_text(p);
        if (<sentence>(W)) {
            parse_node *n = <<rp>>;
            switch (Annotations::read_int(p, linguistic_error_here_ANNOT)) {
                case TwoLikelihoods_LINERROR:
                    Errors::nowhere("sentence has two certainties");
                    break;
                default:
                    SyntaxTree::graft(syntax_tree, n, p);
                    break;
            }
        } else {
            Errors::nowhere("sentence has no primary verb");
        }
    }
}

§4. That sorts out the verbs and prepositions, but the noun phrases are not by default parsed: they are simply left as UNPARSED_NOUN_NT nodes.

void Diagramming::parse_noun_phrases?Usage of Diagramming::parse_noun_phrases:
§2.2(parse_node *p) {
    for (; p; p = p->next) {
        if (Node::get_type(p) == UNPARSED_NOUN_NT) Nouns::recognise(p);
        Diagramming::parse_noun_phrases(p->down);
    }
}