[Spirit] '_' parsed as '\0' with qi::phrase_parse

From: Olaf van der Spek (ml_at_[hidden])
Date: 2022-07-18 07:24:12

Hi,

The underscore is parsed as a null character. Is this expected. A bug?

If a full repro is needed I can create one.

    qi::rule<iterator_t, std::string(), Skip> identifier;
    identifier %= lexeme[alpha >> *(alnum | '.' | '_')];

    typedef boost::spirit::classic::position_iterator<const char*> iterator_t;

    std::string s = "a_b blah";
    iterator_t is(s.c_str(), s.c_str() + s.size(), "<name>");

    std::string out;
    bool res = qi::phrase_parse(is, iterator_t(), identifier, skip, out);
    if (!res && is != iterator_t()) error_handler_::err(is);
    cout << out.size() << "|" << out << "|\n";
    cout << int(out[0]) << " " << int(out[1]) << " " << int(out[2]) << "\n";

Output:
// 3|ab|
// 97 0 98

Greetings,
--
Olaf