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/config/warning_disable.hpp>
  18 #include <boost/spirit/home/x3.hpp>
  19
  20 #include <iostream>
  21 #include <string>
  22 #include <vector>
  23
  24 namespace client
  25 {
  26     namespace x3 = boost::spirit::x3;
  27     namespace ascii = boost::spirit::x3::ascii;
  28
  29     ///////////////////////////////////////////////////////////////////////////
  30     //  Our number list compiler
  31     ///////////////////////////////////////////////////////////////////////////
  32     template <typename Iterator>
  33     bool parse_numbers(Iterator first, Iterator last, std::vector<double>& v)
  34     {
  35         using x3::double_;
  36         using x3::phrase_parse;
  37         using x3::_attr;
  38         using ascii::space;
  39
  40         auto push_back = [&](auto& ctx){ v.push_back(_attr(ctx)); };
  41
  42         bool r = phrase_parse(first, last,
  43
  44             //  Begin grammar
  45             (
  46                 double_[push_back] % ','
  47             )
  48             ,
  49             //  End grammar
  50
  51             space);
  52
  53         if (first != last) // fail if we did not get a full match
  54             return false;
  55         return r;
  56     }
  57 }
  58
  59 ////////////////////////////////////////////////////////////////////////////
  60 //  Main program
  61 ////////////////////////////////////////////////////////////////////////////
  62 int
  63 main()
  64 {
  65     std::cout << "/////////////////////////////////////////////////////////\n\n";
  66     std::cout << "\t\tA comma separated list parser for Spirit...\n\n";
  67     std::cout << "/////////////////////////////////////////////////////////\n\n";
  68
  69     std::cout << "Give me a comma separated list of numbers.\n";
  70     std::cout << "The numbers will be inserted in a vector of numbers\n";
  71     std::cout << "Type [q or Q] to quit\n\n";
  72
  73     std::string str;
  74     while (getline(std::cin, str))
  75     {
  76         if (str.empty() || str[0] == 'q' || str[0] == 'Q')
  77             break;
  78
  79         std::vector<double> v;
  80         if (client::parse_numbers(str.begin(), str.end(), v))
  81         {
  82             std::cout << "-------------------------\n";
  83             std::cout << "Parsing succeeded\n";
  84             std::cout << str << " Parses OK: " << std::endl;
  85
  86             for (std::vector<double>::size_type i = 0; i < v.size(); ++i)
  87                 std::cout << i << ": " << v[i] << std::endl;
  88
  89             std::cout << "\n-------------------------\n";
  90         }
  91         else
  92         {
  93             std::cout << "-------------------------\n";
  94             std::cout << "Parsing failed\n";
  95             std::cout << "-------------------------\n";
  96         }
  97     }
  98
  99     std::cout << "Bye... :-) \n\n";
 100     return 0;
 101 }