num_list4.cpp 3.3 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. // This time, the numbers are automatically collected into the attribute by
  10. // the parser itself using the full power of attribute grammars.
  11. //
  12. // [ JDG May 10, 2002 ] spirit1
  13. // [ JDG March 24, 2007 ] spirit2
  14. // [ JDG May 12, 2015 ] spirit X3
  15. //
  16. ///////////////////////////////////////////////////////////////////////////////
  17. #include <boost/config/warning_disable.hpp>
  18. #include <boost/spirit/home/x3.hpp>
  19. #include <iostream>
  20. #include <string>
  21. #include <vector>
  22. namespace client
  23. {
  24. namespace x3 = boost::spirit::x3;
  25. namespace ascii = boost::spirit::x3::ascii;
  26. ///////////////////////////////////////////////////////////////////////////
  27. // Our number list compiler
  28. ///////////////////////////////////////////////////////////////////////////
  29. //[tutorial_numlist4
  30. template <typename Iterator>
  31. bool parse_numbers(Iterator first, Iterator last, std::vector<double>& v)
  32. {
  33. using x3::double_;
  34. using x3::phrase_parse;
  35. using x3::_attr;
  36. using ascii::space;
  37. bool r = phrase_parse(first, last,
  38. // Begin grammar
  39. (
  40. double_ % ','
  41. )
  42. ,
  43. // End grammar
  44. space, v);
  45. if (first != last) // fail if we did not get a full match
  46. return false;
  47. return r;
  48. }
  49. //]
  50. }
  51. ////////////////////////////////////////////////////////////////////////////
  52. // Main program
  53. ////////////////////////////////////////////////////////////////////////////
  54. int
  55. main()
  56. {
  57. std::cout << "/////////////////////////////////////////////////////////\n\n";
  58. std::cout << "\t\tA comma separated list parser for Spirit...\n\n";
  59. std::cout << "/////////////////////////////////////////////////////////\n\n";
  60. std::cout << "Give me a comma separated list of numbers.\n";
  61. std::cout << "The numbers will be inserted in a vector of numbers\n";
  62. std::cout << "Type [q or Q] to quit\n\n";
  63. std::string str;
  64. while (getline(std::cin, str))
  65. {
  66. if (str.empty() || str[0] == 'q' || str[0] == 'Q')
  67. break;
  68. std::vector<double> v;
  69. if (client::parse_numbers(str.begin(), str.end(), v))
  70. {
  71. std::cout << "-------------------------\n";
  72. std::cout << "Parsing succeeded\n";
  73. std::cout << str << " Parses OK: " << std::endl;
  74. for (std::vector<double>::size_type i = 0; i < v.size(); ++i)
  75. std::cout << i << ": " << v[i] << std::endl;
  76. std::cout << "\n-------------------------\n";
  77. }
  78. else
  79. {
  80. std::cout << "-------------------------\n";
  81. std::cout << "Parsing failed\n";
  82. std::cout << "-------------------------\n";
  83. }
  84. }
  85. std::cout << "Bye... :-) \n\n";
  86. return 0;
  87. }