99 lines
3.3 KiB
C++
99 lines
3.3 KiB
C++
/*=============================================================================
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Copyright (c) 2003 Sam Nabialek
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Copyright (c) 2001-2010 Joel de Guzman
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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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///////////////////////////////////////////////////////////////////////////////
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//
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// The Nabialek trick.
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//
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// [ Sam Nabialek; Somewhere, sometime in 2003... ] spirit1
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// [ JDG November 17, 2009 ] spirit2
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// [ JDG January 10, 2010 ] Updated to use rule pointers
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// for efficiency.
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//
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///////////////////////////////////////////////////////////////////////////////
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#include <boost/config/warning_disable.hpp>
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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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namespace client
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{
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namespace qi = boost::spirit::qi;
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namespace ascii = boost::spirit::ascii;
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///////////////////////////////////////////////////////////////////////////////
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// Our nabialek_trick grammar
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///////////////////////////////////////////////////////////////////////////////
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template <typename Iterator>
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struct nabialek_trick : qi::grammar<
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Iterator, ascii::space_type, qi::locals<qi::rule<Iterator, ascii::space_type>*> >
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{
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nabialek_trick() : nabialek_trick::base_type(start)
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{
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using ascii::alnum;
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using qi::lexeme;
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using qi::lazy;
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using qi::_a;
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using qi::_1;
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id = lexeme[*(ascii::alnum | '_')];
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one = id;
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two = id >> ',' >> id;
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keyword.add
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("one", &one)
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("two", &two)
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;
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start = *(keyword[_a = _1] >> lazy(*_a));
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}
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qi::rule<Iterator, ascii::space_type> id, one, two;
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qi::rule<Iterator, ascii::space_type, qi::locals<qi::rule<Iterator, ascii::space_type>*> > start;
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qi::symbols<char, qi::rule<Iterator, ascii::space_type>*> keyword;
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};
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}
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///////////////////////////////////////////////////////////////////////////////
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// Main program
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///////////////////////////////////////////////////////////////////////////////
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int
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main()
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{
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using boost::spirit::ascii::space;
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typedef std::string::const_iterator iterator_type;
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typedef client::nabialek_trick<iterator_type> nabialek_trick;
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nabialek_trick g; // Our grammar
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std::string str = "one only\none again\ntwo first,second";
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std::string::const_iterator iter = str.begin();
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std::string::const_iterator end = str.end();
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bool r = phrase_parse(iter, end, g, space);
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if (r && iter == end)
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{
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std::cout << "-------------------------\n";
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std::cout << "Parsing succeeded\n";
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std::cout << "-------------------------\n";
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}
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else
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{
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std::string rest(iter, end);
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std::cout << "-------------------------\n";
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std::cout << "Parsing failed\n";
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std::cout << "stopped at: \": " << rest << "\"\n";
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std::cout << "-------------------------\n";
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}
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return 0;
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}
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