ceph/src/boost/libs/spirit/example/qi/nabialek.cpp

   1 /*=============================================================================
   2     Copyright (c) 2003 Sam Nabialek
   3     Copyright (c) 2001-2010 Joel de Guzman
   4
   5     Distributed under the Boost Software License, Version 1.0. (See accompanying
   6     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   7 =============================================================================*/
   8 ///////////////////////////////////////////////////////////////////////////////
   9 //
  10 //  The Nabialek trick.
  11 //
  12 //  [ Sam Nabialek; Somewhere, sometime in 2003... ]    spirit1
  13 //  [ JDG November 17, 2009 ]                           spirit2
  14 //  [ JDG January 10, 2010 ]                            Updated to use rule pointers
  15 //                                                      for efficiency.
  16 //
  17 ///////////////////////////////////////////////////////////////////////////////
  18
  19 #include <boost/spirit/include/qi.hpp>
  20 #include <boost/phoenix/operator.hpp>
  21 #include <iostream>
  22 #include <string>
  23
  24 namespace client
  25 {
  26     namespace qi = boost::spirit::qi;
  27     namespace ascii = boost::spirit::ascii;
  28
  29     ///////////////////////////////////////////////////////////////////////////////
  30     //  Our nabialek_trick grammar
  31     ///////////////////////////////////////////////////////////////////////////////
  32     template <typename Iterator>
  33     struct nabialek_trick : qi::grammar<
  34         Iterator, ascii::space_type, qi::locals<qi::rule<Iterator, ascii::space_type>*> >
  35     {
  36         nabialek_trick() : nabialek_trick::base_type(start)
  37         {
  38             using ascii::alnum;
  39             using qi::lexeme;
  40             using qi::lazy;
  41             using qi::_a;
  42             using qi::_1;
  43
  44             id = lexeme[*(ascii::alnum | '_')];
  45             one = id;
  46             two = id >> ',' >> id;
  47
  48             keyword.add
  49                 ("one", &one)
  50                 ("two", &two)
  51                 ;
  52
  53             start = *(keyword[_a = _1] >> lazy(*_a));
  54         }
  55
  56         qi::rule<Iterator, ascii::space_type> id, one, two;
  57         qi::rule<Iterator, ascii::space_type, qi::locals<qi::rule<Iterator, ascii::space_type>*> > start;
  58         qi::symbols<char, qi::rule<Iterator, ascii::space_type>*> keyword;
  59     };
  60 }
  61
  62 ///////////////////////////////////////////////////////////////////////////////
  63 //  Main program
  64 ///////////////////////////////////////////////////////////////////////////////
  65 int
  66 main()
  67 {
  68     using boost::spirit::ascii::space;
  69     typedef std::string::const_iterator iterator_type;
  70     typedef client::nabialek_trick<iterator_type> nabialek_trick;
  71
  72     nabialek_trick g; // Our grammar
  73
  74     std::string str = "one only\none again\ntwo first,second";
  75     std::string::const_iterator iter = str.begin();
  76     std::string::const_iterator end = str.end();
  77     bool r = phrase_parse(iter, end, g, space);
  78
  79     if (r && iter == end)
  80     {
  81         std::cout << "-------------------------\n";
  82         std::cout << "Parsing succeeded\n";
  83         std::cout << "-------------------------\n";
  84     }
  85     else
  86     {
  87         std::string rest(iter, end);
  88         std::cout << "-------------------------\n";
  89         std::cout << "Parsing failed\n";
  90         std::cout << "stopped at: \": " << rest << "\"\n";
  91         std::cout << "-------------------------\n";
  92     }
  93
  94     return 0;
  95 }
  96
  97