parser2

/*
Trying to get a basic example using my files going. I have a very large file which has many different lines. The following always bails on "could not parse whole file." I've cut the input file down to below.

--- input file ---
This is a test file
1 2 3
*/

namespace myParser
{
    using namespace std;

    namespace x3 = boost::spirit::x3;
    namespace ascii = boost::spirit::x3::ascii;

    using ascii::blank;
    using x3::_attr;
    using x3::char_;
    using x3::double_;
    using x3::eol;
    using x3::int_;
    using x3::parse;
    using x3::skip;

    auto description = *(char_ - eol) >> eol; // 1st line, just comments
    auto numbers = int_ >> int_ >> int_;      // 2nd line, 3 numbers
    auto point = double_ >> double_ >> double_;  // lines 3 - several thousand, 3 doubles
    auto element = int_ >> *(char_) >> int_ >> int_ >> int_; // after points, many of these also

    auto points = skip(blank) [
        *(point >> eol)
    ];

    auto elements = skip(blank) [
        *(element >> eol)
    ];

    auto pr = [&] (auto& ctx) {
        string desc;
        desc = _attr(ctx);
        cout << "desc = " << desc << endl;
    };

    auto input = *description[pr]
        >> numbers;

//        >> points
//        >> elements;
}


int main()
{
    namespace x3 = boost::spirit::x3;

    string bigfile("/tmp/large_file");

    mapped_file_source map(bigfile);
    istringstream ss(map.data());
    ss.close();

    boost::spirit::istream_iterator sof(ss), eof;

    x3::parse(sof, eof,  myParser::input);

    if (sof != eof)
        cout << "Error: could not parse whole file." << endl;
}