//  Copyright (c) 2010 Peter Schueller
// 
//  Distributed under the Boost Software License, Version 1.0. (See accompanying
//  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

#include <vector>
#include <istream>
#include <sstream>
#include <iostream>
#include <boost/spirit/include/qi.hpp>
#include <boost/spirit/include/support_multi_pass.hpp>
#include <boost/spirit/include/classic_position_iterator.hpp>

namespace qi = boost::spirit::qi;
namespace ascii = boost::spirit::ascii;
namespace classic = boost::spirit::classic;

// parse list of doubles from input stream
// throw exception (perhaps including filename) on errors
std::vector<double> parse(std::istream& input, const std::string& filename);

// main function
int main(int, char**)
{
  try
  {
    parse(std::cin, "STDIN");
  }
  catch(const std::exception& e)
  {
    std::cerr << "Exception: " << e.what() << std::endl;
    return -1;
  }
  return 0;
}

// implementation
std::vector<double> parse(std::istream& input, const std::string& filename)
{
  // iterate over stream input
  typedef std::istreambuf_iterator<char> base_iterator_type;
  base_iterator_type in_begin(input);

  // convert input iterator to forward iterator, usable by spirit parser
  typedef boost::spirit::multi_pass<base_iterator_type> forward_iterator_type;
  forward_iterator_type fwd_begin = boost::spirit::make_default_multi_pass(in_begin);
  forward_iterator_type fwd_end;

  // wrap forward iterator with position iterator, to record the position
  typedef classic::position_iterator2<forward_iterator_type> pos_iterator_type;
  pos_iterator_type position_begin(fwd_begin, fwd_end, filename);
  pos_iterator_type position_end;

  // prepare output
  std::vector<double> output;

  // parse
  try
  {
    qi::phrase_parse(
      position_begin, position_end,                               // iterators over input
      qi::double_ > *(',' > qi::double_) >> qi::eoi,              // recognize list of doubles
      ascii::space | '#' >> *(ascii::char_ - qi::eol) >> qi::eol, // comment skipper
      output);                                                    // doubles are stored into this object
  }
  catch(const qi::expectation_failure<pos_iterator_type>& e)
  {
    const classic::file_position_base<std::string>& pos = e.first.get_position();
    std::stringstream msg;
    msg <<
      "parse error at file " << pos.file <<
      " line " << pos.line << " column " << pos.column << std::endl <<
      "'" << e.first.get_currentline() << "'" << std::endl <<
      std::setw(pos.column) << " " << "^- here";
    throw std::runtime_error(msg.str());
  }

  // return result
  return output;
}