/*============================================================================= 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 #include #include #include #include //] //[porting_guide_qi_namespace using namespace boost::spirit; //] //[porting_guide_qi_grammar template struct roman : qi::grammar { 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 first; qi::symbols hundreds; qi::symbols tens; qi::symbols 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 r; if (qi::parse(it, input.end(), r, value)) std::cout << "successfully matched: " << value << "\n"; //] } return 0; }