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  1. #include <iostream>
  2. #include <map>
  3. #include <memory>
  4. #include <string>
  5.  
  6. #define CONCAT(x, y) CONCAT_(x, y)
  7. #define CONCAT_(x, y) x ## y
  8.  
  9. #define PAR(type, name, descr) \
  10. type name; \
  11. const bool CONCAT(doRegistration, __LINE__) = []() { \
  12.     entries.emplace(#name, \
  13.                     std::unique_ptr<BaseEntry>( \
  14.                         new Entry<Model, type>{ type##_type, &Model::name })); \
  15.     return true; \
  16. }();
  17.  
  18. enum ParType { double_type, int_type };
  19.  
  20. class Model;
  21.  
  22. struct BaseEntry
  23. {
  24.     BaseEntry(ParType type) : type(type) {}
  25.     ParType type;
  26.  
  27.     template <typename C, typename T>
  28.     T & get(C &c);
  29. };
  30.  
  31. template <typename C, typename T>
  32. struct Entry : BaseEntry
  33. {
  34.     Entry(ParType type, T C::* ptr) : BaseEntry(type), ptr(ptr) {}
  35.     T C::* ptr;
  36. };
  37.  
  38. template <typename C, typename T>
  39. T & BaseEntry::get(C &c)
  40. {
  41.     return c.*static_cast<Entry<C, T>*>(this)->ptr;
  42. }
  43.  
  44. class Model
  45. {
  46. public:
  47.     Model() : a(1.0), b(2) {}
  48.  
  49.     static std::map<std::string, std::unique_ptr<BaseEntry>> entries;
  50.  
  51.     PAR(double, a, "какой то параметр");
  52.     PAR(int, b, "и еще один параметр");
  53. };
  54.  
  55. std::map<std::string, std::unique_ptr<BaseEntry>> Model::entries;
  56.  
  57. int
  58. main(void)
  59. {
  60.     Model m;
  61.     for (const auto &e : m.entries) {
  62.         std::cout << e.first << std::endl;
  63.         switch (e.second->type) {
  64.             case double_type:
  65.                 e.second->get<Model, double>(m) = 10.1;
  66.                 std::cout << e.second->get<Model, double>(m) << std::endl;
  67.                 break;
  68.             case int_type:
  69.                 std::cout << e.second->get<Model, int>(m) << std::endl;
  70.                 break;
  71.         }
  72.     }
  73.     return 0;
  74. }
  75.  
Success #stdin #stdout 0s 3472KB
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Standard input is empty
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a
10.1
b
2
https://ideone.com/YH43Gk
language:
C++14 (gcc 8.3)
created:
8 years ago
visibility:
public

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