107 lines
3.3 KiB
C++
107 lines
3.3 KiB
C++
/*=============================================================================
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Copyright (c) 2001-2011 Hartmut Kaiser
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http://spirit.sourceforge.net/
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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=============================================================================*/
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//[porting_guide_qi_includes
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#include <boost/spirit/include/qi.hpp>
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#include <boost/spirit/include/phoenix_operator.hpp>
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#include <iostream>
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#include <string>
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#include <algorithm>
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//]
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//[porting_guide_qi_namespace
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using namespace boost::spirit;
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//]
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//[porting_guide_qi_grammar
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template <typename Iterator>
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struct roman : qi::grammar<Iterator, unsigned()>
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{
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roman() : roman::base_type(first)
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{
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hundreds.add
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("C" , 100)("CC" , 200)("CCC" , 300)("CD" , 400)("D" , 500)
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("DC" , 600)("DCC" , 700)("DCCC" , 800)("CM" , 900) ;
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tens.add
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("X" , 10)("XX" , 20)("XXX" , 30)("XL" , 40)("L" , 50)
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("LX" , 60)("LXX" , 70)("LXXX" , 80)("XC" , 90) ;
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ones.add
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("I" , 1)("II" , 2)("III" , 3)("IV" , 4)("V" , 5)
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("VI" , 6)("VII" , 7)("VIII" , 8)("IX" , 9) ;
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// qi::_val refers to the attribute of the rule on the left hand side
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first = eps [qi::_val = 0]
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>> ( +lit('M') [qi::_val += 1000]
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|| hundreds [qi::_val += qi::_1]
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|| tens [qi::_val += qi::_1]
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|| ones [qi::_val += qi::_1]
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) ;
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}
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qi::rule<Iterator, unsigned()> first;
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qi::symbols<char, unsigned> hundreds;
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qi::symbols<char, unsigned> tens;
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qi::symbols<char, unsigned> ones;
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};
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//]
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int main()
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{
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{
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//[porting_guide_qi_parse
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std::string input("1,1");
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std::string::iterator it = input.begin();
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bool result = qi::parse(it, input.end(), qi::int_);
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if (result)
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std::cout << "successful match!\n";
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if (it == input.end())
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std::cout << "full match!\n";
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else
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std::cout << "stopped at: " << std::string(it, input.end()) << "\n";
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// seldomly needed: use std::distance to calculate the length of the match
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std::cout << "matched length: " << std::distance(input.begin(), it) << "\n";
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//]
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}
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{
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//[porting_guide_qi_phrase_parse
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std::string input(" 1, 1");
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std::string::iterator it = input.begin();
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bool result = qi::phrase_parse(it, input.end(), qi::int_, ascii::space);
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if (result)
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std::cout << "successful match!\n";
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if (it == input.end())
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std::cout << "full match!\n";
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else
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std::cout << "stopped at: " << std::string(it, input.end()) << "\n";
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// seldomly needed: use std::distance to calculate the length of the match
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std::cout << "matched length: " << std::distance(input.begin(), it) << "\n";
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//]
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}
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{
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//[porting_guide_qi_use_grammar
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std::string input("MMIX"); // MMIX == 2009
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std::string::iterator it = input.begin();
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unsigned value = 0;
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roman<std::string::iterator> r;
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if (qi::parse(it, input.end(), r, value))
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std::cout << "successfully matched: " << value << "\n";
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//]
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}
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return 0;
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}
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