ceph/src/boost/libs/spirit/example/x3/num_list/num_list3.cpp

   1 /*=============================================================================
   2     Copyright (c) 2002-2015 Joel de Guzman
   3
   4     Distributed under the Boost Software License, Version 1.0. (See accompanying
   5     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   6 =============================================================================*/
   7 ///////////////////////////////////////////////////////////////////////////////
   8 //
   9 //  This sample demontrates a parser for a comma separated list of numbers.
  10 //
  11 //  [ JDG May 10, 2002 ]    spirit1
  12 //  [ JDG March 24, 2007 ]  spirit2
  13 //  [ JDG May 12, 2015 ]    spirit X3
  14 //
  15 ///////////////////////////////////////////////////////////////////////////////
  16
  17 #include <boost/spirit/home/x3.hpp>
  18
  19 #include <iostream>
  20 #include <string>
  21 #include <vector>
  22
  23 namespace client
  24 {
  25     namespace x3 = boost::spirit::x3;
  26     namespace ascii = boost::spirit::x3::ascii;
  27
  28     ///////////////////////////////////////////////////////////////////////////
  29     //  Our number list compiler
  30     ///////////////////////////////////////////////////////////////////////////
  31     template <typename Iterator>
  32     bool parse_numbers(Iterator first, Iterator last, std::vector<double>& v)
  33     {
  34         using x3::double_;
  35         using x3::phrase_parse;
  36         using x3::_attr;
  37         using ascii::space;
  38
  39         auto push_back = [&](auto& ctx){ v.push_back(_attr(ctx)); };
  40
  41         bool r = phrase_parse(first, last,
  42
  43             //  Begin grammar
  44             (
  45                 double_[push_back] % ','
  46             )
  47             ,
  48             //  End grammar
  49
  50             space);
  51
  52         if (first != last) // fail if we did not get a full match
  53             return false;
  54         return r;
  55     }
  56 }
  57
  58 ////////////////////////////////////////////////////////////////////////////
  59 //  Main program
  60 ////////////////////////////////////////////////////////////////////////////
  61 int
  62 main()
  63 {
  64     std::cout << "/////////////////////////////////////////////////////////\n\n";
  65     std::cout << "\t\tA comma separated list parser for Spirit...\n\n";
  66     std::cout << "/////////////////////////////////////////////////////////\n\n";
  67
  68     std::cout << "Give me a comma separated list of numbers.\n";
  69     std::cout << "The numbers will be inserted in a vector of numbers\n";
  70     std::cout << "Type [q or Q] to quit\n\n";
  71
  72     std::string str;
  73     while (getline(std::cin, str))
  74     {
  75         if (str.empty() || str[0] == 'q' || str[0] == 'Q')
  76             break;
  77
  78         std::vector<double> v;
  79         if (client::parse_numbers(str.begin(), str.end(), v))
  80         {
  81             std::cout << "-------------------------\n";
  82             std::cout << "Parsing succeeded\n";
  83             std::cout << str << " Parses OK: " << std::endl;
  84
  85             for (std::vector<double>::size_type i = 0; i < v.size(); ++i)
  86                 std::cout << i << ": " << v[i] << std::endl;
  87
  88             std::cout << "\n-------------------------\n";
  89         }
  90         else
  91         {
  92             std::cout << "-------------------------\n";
  93             std::cout << "Parsing failed\n";
  94             std::cout << "-------------------------\n";
  95         }
  96     }
  97
  98     std::cout << "Bye... :-) \n\n";
  99     return 0;
 100 }