I try some codes snippet from boost spirit, but it only incur a lot of error mesasges


void spirit_01()
  namespace qi = boost::spirit::qi;
  std::string input("1.0,2.0");
  std::pair<double, double> p;
  qi::parse(input.begin(), input.end(), qi::double_ >> ",">>qi::double_, p); //#1
After some struggle, I figured it out the compiler say it needs two arguments
the correct answer is

double a, b;
qi::parse(input.begin(), input.end(), qi::double_ >> ",">>qi::double_, a, b);
What am I lack to make #1 compile?Thanks

I choose boost::spirit to develop some parsers and source codes generator
When I deal with something like xml or some repetitive codes, codes
generator could be very useful.

Although I consider that boost::regex could make the job done too, but learning
how to work with boost::spirit may give me more flexibility. Besides, I heard
that the performance of boost::spirit is splendid?