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  1. // Create class members and methods with X-Macros
  2. // Klaus Warnke
  3.  
  4. #include <string>
  5. #include <tuple>
  6. #include <iostream>
  7. #include <cassert>
  8.  
  9. #define MEMBER_TBL                        \
  10.     /*type        ,name ,default*/        \
  11.     X(int         ,_(i) ,42     )         \
  12.     X(float       ,_(f) ,3.14   )         \
  13.     X(std::string ,  t  ,"Hello")         \
  14.  
  15. struct Foo
  16. {
  17. #define _(x) x
  18. #define X(type, name, default) type name{default};
  19.     MEMBER_TBL
  20. #undef X
  21. #undef _
  22.  
  23.     bool operator==(Foo const& other) const {
  24.         return  std::tie(
  25. #define _(x) x,
  26. #define X(type, name, default) this->name
  27.             MEMBER_TBL
  28. #undef X
  29.         ) == std::tie(
  30. #define X(type, name, default) other.name
  31.             MEMBER_TBL
  32. #undef X
  33. #undef _
  34.         );
  35.     }
  36.  
  37.     void print() const { 
  38. #define STR(x) #x
  39. #define _(x) x
  40. #define X(type, name, default)            \
  41.         std::cout <<                      \
  42.             STR(name) << ": " << name << " ";
  43.         MEMBER_TBL
  44. #undef X
  45. #undef _
  46. #undef STR
  47.         std::cout << std::endl;
  48.     }
  49. };
  50.  
  51. #undef _
  52. #undef MEMBER_TBL
  53.  
  54. int main(void) 
  55. {
  56.     Foo foo{}, bar{};
  57.  
  58.     assert(foo == bar);
  59.     bar.t = "bye";
  60.     assert(! (foo == bar));
  61.  
  62.     foo.print(); // i: 42 f: 3.14 t: Hello 
  63.     bar.print(); // i: 42 f: 3.14 t: bye 
  64.  
  65.     return 0;
  66. }
  67.  
Success #stdin #stdout 0s 3416KB
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Standard input is empty
stdout
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i: 42 f: 3.14 t: Hello 
i: 42 f: 3.14 t: bye
https://ideone.com/mlVjla
Create class members and methods with X-Macros
language:
C++14 (gcc 8.3)
created:
8 years ago
visibility:
public

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