static bool scan_automatic_semicolon()

in tree-sitter-mozjs/src/scanner.c [110:223]

• 88 lines of code
• 42 McCabe index (conditional complexity)

static bool scan_automatic_semicolon(TSLexer *lexer, bool comment_condition, bool *scanned_comment) {
    lexer->result_symbol = AUTOMATIC_SEMICOLON;
    lexer->mark_end(lexer);

    for (;;) {
        if (lexer->lookahead == 0) {
            return true;
        }

        if (lexer->lookahead == '/') {
            WhitespaceResult result = scan_whitespace_and_comments(lexer, scanned_comment, false);
            if (result == REJECT) {
                return false;
            }

            if (result == ACCEPT && comment_condition && lexer->lookahead != ',' && lexer->lookahead != '=') {
                return true;
            }
        }

        if (lexer->lookahead == '}') {
            return true;
        }

        if (lexer->is_at_included_range_start(lexer)) {
            return true;
        }

        if (lexer->lookahead == '\n' || lexer->lookahead == 0x2028 || lexer->lookahead == 0x2029) {
            break;
        }

        if (!iswspace(lexer->lookahead)) {
            return false;
        }

        skip(lexer);
    }

    skip(lexer);

    if (scan_whitespace_and_comments(lexer, scanned_comment, true) == REJECT) {
        return false;
    }

    switch (lexer->lookahead) {
        case '`':
        case ',':
        case ':':
        case ';':
        case '*':
        case '%':
        case '>':
        case '<':
        case '=':
        case '[':
        case '(':
        case '?':
        case '^':
        case '|':
        case '&':
        case '/':
            return false;

        // Insert a semicolon before decimals literals but not otherwise.
        case '.':
            skip(lexer);
            return iswdigit(lexer->lookahead);

        // Insert a semicolon before `--` and `++`, but not before binary `+` or `-`.
        case '+':
            skip(lexer);
            return lexer->lookahead == '+';
        case '-':
            skip(lexer);
            return lexer->lookahead == '-';

        // Don't insert a semicolon before `!=`, but do insert one before a unary `!`.
        case '!':
            skip(lexer);
            return lexer->lookahead != '=';

        // Don't insert a semicolon before `in` or `instanceof`, but do insert one
        // before an identifier.
        case 'i':
            skip(lexer);

            if (lexer->lookahead != 'n') {
                return true;
            }
            skip(lexer);

            if (!iswalpha(lexer->lookahead)) {
                return false;
            }

            for (unsigned i = 0; i < 8; i++) {
                if (lexer->lookahead != "stanceof"[i]) {
                    return true;
                }
                skip(lexer);
            }

            if (!iswalpha(lexer->lookahead)) {
                return false;
            }
            break;

        default:
            break;
    }

    return true;
}