[boost] [spirit]

Subject: [boost] [spirit]
From: Chandrashekhar Kumar (iitk.cs_at_[hidden])
Date: 2009-06-04 14:58:54

Hi,

I have to parse the file, the contents of which(with a header) is below and
stuff the double part only to std::vector<double>:

"A","B","C","D"
1,2,3,4
5,6.7,8
........

I started simple without header approach first :

from libs/spirit/example/lex/example.hpp:

inline std::string
read_from_file(char const* infile)
{
    std::ifstream instream(infile);
    if (!instream.is_open()) {
        std::cerr << "Couldn't open file: " << infile << std::endl;
        exit(-1);
    }
    instream.unsetf(std::ios::skipws);      // No white space skipping!
    return std::string(std::istreambuf_iterator<char>(instream.rdbuf()),
                       std::istreambuf_iterator<char>());
}

from libs/spirit/classic/examples/number_list.hpp:

///////////////////////////////////////////////////////////////////////////////
//
//  Our comma separated list parser
//
///////////////////////////////////////////////////////////////////////////////
bool
parse_numbers(char const* str, vector<double>& v)
{
    return parse(str,

        //  Begin grammar
        (
            real_p[push_back_a(v)] >> *(',' >> real_p[push_back_a(v)])
        )
        ,
        //  End grammar

        space_p).full;
}

int main()
{
    std::string str = read_from_file("test.csv");

    std::vector<double> v;

     if (parse_numbers(str.c_str(), v))
        {
            cout << "-------------------------\n";
            cout << "Parsing succeeded\n";
            cout << str << " Parses OK: " << endl;

            for (vector<double>::size_type i = 0; i < v.size(); ++i)
                cout << i << ": " << v[i] << endl;

            cout << "-------------------------\n";
        }
        else
        {
            cout << "-------------------------\n";
            cout << "Parsing failed\n";
            cout << "-------------------------\n";
        }
}

But after running it, I am getting the result as "Parsing failed".

I am going thru the doc to understand it better, but any quick spot will
help me immensely.

Thanks,
Chandra