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- /*=============================================================================
- Copyright (c) 2001-2011 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;
- }
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