#include <boost/config/warning_disable.hpp>
#include <boost/spirit/include/qi.hpp>
#include <boost/spirit/include/phoenix_operator.hpp>
 
#include <iostream>
#include <string>
 
namespace qi = boost::spirit::qi;
namespace ascii = boost::spirit::ascii;
struct HEXNUM :qi::symbols<char,int>
{
    
    HEXNUM()
    {
        add("0",0);
        add("1",1);
        add("2",2);
        add("3",3);
        add("4",4);
        add("5",5);
        add("6",6);
        add("7",7);
        add("8",8);
        add("9",9);
        add("a",10);
        add("A",10);
        add("b",11);
        add("B",11);
        add("c",12);
        add("C",12);
        add("d",13);
        add("D",13);
        add("e",14);
        add("E",14);
        add("f",15);
        add("F",15);
    }
}hexnum;
template<class Iter>
class Grama:public qi::grammar<Iter, int()>
{
public:
    Grama():Grama::base_type(hexrule){
        using qi::_val;
        using qi::_1;
        using qi::eps;
        using qi::lit;
        using qi::char_;
 
        hexrule = (lit("0x")[_val=1]|lit("0X")[_val=0])>>
                hexnum[_val=_1]>>*(hexnum [_val = 16*_val+_1] );
    }
private:
    qi::rule<Iter, int()> hexrule;
};
 
int main()
{
  std::cout << "/////////////////////////////////////////////////////////\n\n";
  std::cout << "\t\tHex Numerals Parser\n\n";
  std::cout << "/////////////////////////////////////////////////////////\n\n";
  std::cout << "Type a Hex Numeral ...or [q or Q] to quit\n\n";

  typedef std::string::const_iterator iterator_type;
  typedef Grama<iterator_type>        GRAMA;

  GRAMA grama;

  std::string str;
  unsigned    result;
  while (std::getline(std::cin, str)) {
    if (str.empty() || str[0] == 'q' || str[0] == 'Q') break;

    std::string::const_iterator iter = str.begin();
    std::string::const_iterator end  = str.end();
    bool                        r    = parse(iter, end, grama, result);

    if (r && iter == end) {
      std::cout << "-------------------------\n";
      std::cout << "Parsing succeeded\n";
      std::cout << "result = " << result << std::endl;
      std::cout << "-------------------------\n";
    } else {
      std::string rest(iter, end);
      std::cout << "-------------------------\n";
      std::cout << "Parsing failed\n";
      std::cout << "stopped at: \": " << rest << "\"\n";
      std::cout << "-------------------------\n";
    }
  }

  std::cout << "Bye... :-) \n\n";
  return 0;
}