num_list2.cpp 3.2 KB

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