ceph/src/boost/libs/spirit/classic/example/techniques/dynamic_rule.cpp

   1 /*=============================================================================
   2     Copyright (c) 2003 Jonathan de Halleux (dehalleux@pelikhan.com)
   3     http://spirit.sourceforge.net/
   4
   5     Use, modification and distribution is subject to the Boost Software
   6     License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
   7     http://www.boost.org/LICENSE_1_0.txt)
   8 =============================================================================*/
   9 ///////////////////////////////////////////////////////////////////////////////
  10 // This example shows how the assign operator can be used to modify
  11 // rules with semantic actions
  12 //
  13 // First we show the basic spirit without (without any dynamic feature),
  14 // then we show how to use assign_a to make it dynamic,
  15 //
  16 // the grammar has to parse abcabc... sequences
  17 ///////////////////////////////////////////////////////////////////////////////
  18 #include <iostream>
  19
  20 #define BOOST_SPIRIT_DEBUG
  21 #include <boost/spirit.hpp>
  22
  23 #include <boost/spirit/include/classic_assign_actor.hpp>
  24
  25 int main(int argc, char* argv[])
  26 {
  27     using namespace BOOST_SPIRIT_CLASSIC_NS;
  28     using namespace std;
  29
  30     rule<> a,b,c,next;
  31     const char* str="abcabc";
  32     parse_info<> hit;
  33     BOOST_SPIRIT_DEBUG_NODE(next);
  34     BOOST_SPIRIT_DEBUG_NODE(a);
  35     BOOST_SPIRIT_DEBUG_NODE(b);
  36     BOOST_SPIRIT_DEBUG_NODE(c);
  37
  38     // basic spirit gram
  39     a = ch_p('a') >> !b;
  40     b = ch_p('b') >> !c;
  41     c = ch_p('c') >> !a;
  42
  43     hit = parse(str, a);
  44     cout<<"hit :"<<( hit.hit ? "yes" : "no")<<", "
  45         <<(hit.full ? "full": "not full")
  46         <<endl;
  47
  48     // using assign_a
  49     a = ch_p('a')[ assign_a( next, b)] >> !next;
  50     b = ch_p('b')[ assign_a( next, c)] >> !next;
  51     c = ch_p('c')[ assign_a( next, a)] >> !next;
  52     hit = parse(str, a);
  53     cout<<"hit :"<<( hit.hit ? "yes" : "no")<<", "
  54         <<(hit.full ? "full": "not full")
  55         <<endl;
  56
  57     return 0;
  58 }