How to parse csv using boost::spirit

Question

I have this csv line

std::string s = R\"(1997,Ford,E350,\"ac, abs, moon\",\"some \"rusty\" parts\",3000.00)\";

I can parse it using

Answer 1

For a background on parsing (optionally) quoted delimited fields, including different quoting characters (', "), see here:

• Parse quoted strings with boost::spirit

For a very, very, very complete example complete with support for partially quoted values and a

splitInto(input, output, ' ');

method that takes 'arbitrary' output containers and delimiter expressions, see here:

• How to make my split work only on one real line and be capable to skip quoted parts of string?

Addressing your exact question, assuming either quoted or unquoted fields (no partial quotes inside field values), using Spirit V2:

Let's take the simplest 'abstract datatype' that could possibly work:

using Column  = std::string;
using Columns = std::vector;
using CsvLine = Columns;
using CsvFile = std::vector;

And the repeated double-quote escapes a double-quote semantics (as I pointed out in the comment), you should be able to use something like:

static const char colsep = ',';

start  = -line % eol;
line   = column % colsep;
column = quoted | *~char_(colsep);
quoted = '"' >> *("\"\"" | ~char_('"')) >> '"';

The following complete test program prints

[1997][Ford][E350][ac, abs, moon][rusty][3001.00]

(Note the BOOST_SPIRIT_DEBUG define for easy debugging). See it Live on Coliru

Full Demo

//#define BOOST_SPIRIT_DEBUG
#include 

namespace qi = boost::spirit::qi;

using Column  = std::string;
using Columns = std::vector;
using CsvLine = Columns;
using CsvFile = std::vector;

template 
struct CsvGrammar : qi::grammar
{
    CsvGrammar() : CsvGrammar::base_type(start)
    {
        using namespace qi;

        static const char colsep = ',';

        start  = -line % eol;
        line   = column % colsep;
        column = quoted | *~char_(colsep);
        quoted = '"' >> *("\"\"" | ~char_('"')) >> '"';

        BOOST_SPIRIT_DEBUG_NODES((start)(line)(column)(quoted));
    }
  private:
    qi::rule start;
    qi::rule line;
    qi::rule column;
    qi::rule quoted;
};

int main()
{
    const std::string s = R"(1997,Ford,E350,"ac, abs, moon","""rusty""",3001.00)";

    auto f(begin(s)), l(end(s));
    CsvGrammar p;

    CsvFile parsed;
    bool ok = qi::phrase_parse(f,l,p,qi::blank,parsed);

    if (ok)
    {
        for(auto& line : parsed) {
            for(auto& col : line)
                std::cout << '[' << col << ']';
            std::cout << std::endl;
        }
    } else
    {
        std::cout << "Parse failed\n";
    }

    if (f!=l)
        std::cout << "Remaining unparsed: '" << std::string(f,l) << "'\n";
}