Boost C++ Libraries: Ticket #12932: "Char >> (Literal | Sequence)" unpacking

anonymous — Fri, 24 Mar 2017 22:17:22 GMT

Similarly, substituting this rule seems to generate the same result:

            qi::char_ >> ((qi::char_ >> qi::char_ >> qi::char_) - "Z"),

Am I missing something trivial here?

Amine — Mon, 01 May 2017 10:30:36 GMT

The attribute of the parser (qi::char_ >> qi::char_ >> qi::char_) is boost::fusion::vector3<char, char, char> so you should write your code this way :

#include <boost/spirit/include/qi.hpp>
#include <cstdlib>
#include <iostream>
#include <string>
int main(int argc, char * argv[]) {
    namespace qi = boost::spirit::qi;
    namespace fusion = boost::fusion;
    const std::string input("xabc");
    char x = 0;
    fusion::vector3<char, char, char> v;
    const int result = qi::parse(
        input.begin(),
        input.end(),
            qi::char_ >> (qi::lit("Z") | (qi::char_ >> qi::char_ >> qi::char_)),
            x, v
    );
    std::cout << (result ? "Success" : "Failure") << ": "
        << '"' << x << "\" \"" << fusion::at_c<0>(v) << "\" \""
                               << fusion::at_c<1>(v) << "\" \""
                               << fusion::at_c<2>(v) << '"' << std::endl;
    return result ? EXIT_SUCCESS : EXIT_FAILURE;
}

keywords, type, summary changed

Thu, 14 Dec 2017 17:14:20 GMT

keywords unpacking added; or sequence removed
type Bugs → Feature Requests
summary Boost Spirit 1.63 "Char >> (Literal | Sequence)" Bug → "Char >> (Literal | Sequence)" unpacking

Amine is right here, though it is actually optional<vector3<char, char, char>>. I consider this not a bug, but feature request.