| /*============================================================================= |
| Copyright (c) 2001-2010 Hartmut Kaiser |
| http://spirit.sourceforge.net/ |
| |
| 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) |
| =============================================================================*/ |
| //[porting_guide_qi_includes |
| #include <boost/spirit/include/qi.hpp> |
| #include <boost/spirit/include/phoenix_operator.hpp> |
| #include <iostream> |
| #include <string> |
| #include <algorithm> |
| //] |
| |
| //[porting_guide_qi_namespace |
| using namespace boost::spirit; |
| //] |
| |
| //[porting_guide_qi_grammar |
| template <typename Iterator> |
| struct roman : qi::grammar<Iterator, unsigned()> |
| { |
| roman() : roman::base_type(first) |
| { |
| hundreds.add |
| ("C" , 100)("CC" , 200)("CCC" , 300)("CD" , 400)("D" , 500) |
| ("DC" , 600)("DCC" , 700)("DCCC" , 800)("CM" , 900) ; |
| |
| tens.add |
| ("X" , 10)("XX" , 20)("XXX" , 30)("XL" , 40)("L" , 50) |
| ("LX" , 60)("LXX" , 70)("LXXX" , 80)("XC" , 90) ; |
| |
| ones.add |
| ("I" , 1)("II" , 2)("III" , 3)("IV" , 4)("V" , 5) |
| ("VI" , 6)("VII" , 7)("VIII" , 8)("IX" , 9) ; |
| |
| // qi::_val refers to the attribute of the rule on the left hand side |
| first = eps [qi::_val = 0] |
| >> ( +lit('M') [qi::_val += 1000] |
| || hundreds [qi::_val += qi::_1] |
| || tens [qi::_val += qi::_1] |
| || ones [qi::_val += qi::_1] |
| ) ; |
| } |
| |
| qi::rule<Iterator, unsigned()> first; |
| qi::symbols<char, unsigned> hundreds; |
| qi::symbols<char, unsigned> tens; |
| qi::symbols<char, unsigned> ones; |
| }; |
| //] |
| |
| int main() |
| { |
| { |
| //[porting_guide_qi_parse |
| std::string input("1,1"); |
| std::string::iterator it = input.begin(); |
| bool result = qi::parse(it, input.end(), qi::int_); |
| |
| if (result) |
| std::cout << "successful match!\n"; |
| |
| if (it == input.end()) |
| std::cout << "full match!\n"; |
| else |
| std::cout << "stopped at: " << std::string(it, input.end()) << "\n"; |
| |
| // seldomly needed: use std::distance to calculate the length of the match |
| std::cout << "matched length: " << std::distance(input.begin(), it) << "\n"; |
| //] |
| } |
| |
| { |
| //[porting_guide_qi_phrase_parse |
| std::string input(" 1, 1"); |
| std::string::iterator it = input.begin(); |
| bool result = qi::phrase_parse(it, input.end(), qi::int_, ascii::space); |
| |
| if (result) |
| std::cout << "successful match!\n"; |
| |
| if (it == input.end()) |
| std::cout << "full match!\n"; |
| else |
| std::cout << "stopped at: " << std::string(it, input.end()) << "\n"; |
| |
| // seldomly needed: use std::distance to calculate the length of the match |
| std::cout << "matched length: " << std::distance(input.begin(), it) << "\n"; |
| //] |
| } |
| |
| { |
| //[porting_guide_qi_use_grammar |
| std::string input("MMIX"); // MMIX == 2009 |
| std::string::iterator it = input.begin(); |
| unsigned value = 0; |
| roman<std::string::iterator> r; |
| if (qi::parse(it, input.end(), r, value)) |
| std::cout << "successfully matched: " << value << "\n"; |
| //] |
| } |
| return 0; |
| } |
| |