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  1. #include <iostream>
  2. #include <typeinfo>
  3. #include <cxxabi.h>
  4. using namespace std;
  5.  
  6. // demangle from https://stackoverflow.com/questions/11347373/issue-with-type-name-demangling
  7. string demangle(const char* mangledName) {
  8.     int status;
  9.     char* result = abi::__cxa_demangle(mangledName, nullptr, nullptr, &status);
  10.     switch(status) {
  11.     case -1:
  12.         cerr << "Out of memory!" << endl;
  13.         exit(1);
  14.     case -2:
  15.         return mangledName;
  16.     case -3: 
  17.         return mangledName;
  18.     }
  19.     string name = result;
  20.     free(result);
  21.     return name;
  22. }
  23. //
  24.  
  25. // START //
  26.  
  27.  
  28. template <typename...>
  29. struct type_list{};
  30.  
  31. template<template <typename...> typename tmpl> 
  32. struct tmpl_c
  33. {
  34. 	template <typename...Ts> using type = tmpl<Ts...>;
  35. };
  36.  
  37. template<typename> struct template_of;
  38. template <template <typename...> typename tmpl, typename... Ts>
  39. struct template_of<tmpl<Ts...>>{
  40.     using type = tmpl_c<tmpl>; 
  41. };
  42.  
  43.  
  44. template <typename T>
  45. struct first{};
  46.  
  47.  
  48. template <typename T>
  49. struct second
  50. {
  51. 	// 'second' here refers to second<int>
  52. 	using test = second; 
  53.  
  54. 	// 'second' here refers to the template second
  55. 	// is this due to the context? ie that the tmpl_c is expecting a template not a concrete type?
  56. 	using types = type_list<tmpl_c<first>, tmpl_c<second> >; 
  57.  
  58.  
  59. 	// second here refers to the concrete type 'second<int>'
  60. 	// this workaround is needed for visual studio as it seems second always 
  61. 	// refers to the concrete type, not the template.
  62. 	using types2 = type_list<tmpl_c<first>, typename template_of<second>::type >; 
  63. };
  64.  
  65. template <typename...Ts>
  66. void print_types(type_list<Ts...>)
  67. {
  68. 	using do_ = int[];
  69. 	(void)do_{0,
  70. 		(std::cout << demangle(typeid(Ts).name()) << std::endl,0)
  71. 	...,0};
  72. }
  73.  
  74. int main() {
  75.  
  76.  
  77. 	std::cout << demangle(typeid(second<int>::test).name()) << std::endl;
  78. 	print_types(second<int>::types());
  79. 	print_types(second<int>::types2());
  80. }
Success #stdin #stdout 0s 4520KB
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stdin
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Standard input is empty
stdout
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second<int>
tmpl_c<first>
tmpl_c<second>
tmpl_c<first>
tmpl_c<second>
https://ideone.com/I4Jvdm
language:
C++14 (gcc 8.3)
created:
7 years ago
visibility:
public

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