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  1. #include <iostream>
  2. #include <tuple>
  3. #include <typeinfo>
  4. using namespace std;
  5.  
  6. template <typename PRECISION, int R, int C>
  7. struct Matrix
  8. {
  9. 	Matrix() {}
  10. };
  11.  
  12. template <typename DERIVED>
  13. struct VariableTraits
  14. {
  15.     //        static const int DIM;
  16. };
  17.  
  18. template <typename DERIVED>
  19. struct WrappedTraits
  20. {
  21.     //        static const int DIM;
  22.     //        typedef std::tuple<VARIABLE0, VARIABLE1, ...> VARIABLES;
  23. };
  24.  
  25. template <int N, typename WRAPPER>
  26. struct WrappedType
  27. {
  28.     typedef WrappedTraits<WRAPPER> Traits;
  29.     static const int DIM = Traits::DIM;
  30.     typedef typename Traits::VARIABLES VARIABLES;
  31.     typedef Matrix<float, Traits::DIM, VariableTraits<typename std::tuple_element<N, VARIABLES>::type>::DIM> type;
  32. };
  33.  
  34. template<int N, typename WRAPPER>
  35. struct MatrixTypeImpl
  36. {
  37.     typedef std::tuple<typename MatrixTypeImpl<N - 1, WRAPPER>::type, typename WrappedType<N, WRAPPER>::type> type;
  38. };
  39.  
  40. template <typename WRAPPER>
  41. struct MatrixTypeImpl<0, WRAPPER>
  42. {     
  43. 	typedef typename WrappedType<0, WRAPPER>::type type;
  44. };
  45.  
  46. template<typename WRAPPER>
  47. struct MatrixType
  48. {
  49.     typedef WrappedTraits<WRAPPER> Traits;
  50.     typedef typename MatrixTypeImpl<std::tuple_size<typename Traits::VARIABLES>::value - 1, WRAPPER>::type type;
  51. };
  52.  
  53. struct FooVariable
  54. {
  55. };
  56.  
  57. struct BarVariable
  58. {
  59. };
  60.  
  61. template <>
  62. struct VariableTraits<FooVariable>
  63. {
  64.     static const int DIM = 2;
  65. };
  66.  
  67. template <>
  68. struct VariableTraits<BarVariable>
  69. {
  70.     static const int DIM = 3;
  71. };
  72.  
  73. struct Wrapper
  74. {
  75. };
  76.  
  77. template <>
  78. struct WrappedTraits<Wrapper>
  79. {
  80.     static const int DIM = 2;
  81.     typedef std::tuple<FooVariable, BarVariable> VARIABLES;
  82. };
  83.  
  84. template <int N, typename WRAPPER>
  85. void hello(const typename std::tuple_element<N, typename MatrixType<WRAPPER>::type>::type& mat)
  86. {
  87.  
  88. }
  89.  
  90. int main()
  91. {
  92.     typedef typename MatrixType<Wrapper>::type MatrixTuple;
  93.  
  94. 	Matrix<float, 2, 2> FooMatrix;
  95. 	Matrix<float, 2, 3> BarMatrix;
  96. //	typedef typename std::tuple_element<0, MatrixTuple>::type FooMatrixType;
  97. //	typedef typename std::tuple_element<1, MatrixTuple>::type BarMatrixType;
  98. //	std::cout << typeid(FooMatrixType).name() << std::endl;
  99. //	std::cout << typeid(BarMatrixType).name() << std::endl;
  100.  
  101. //	FooMatrixType FooMatrix;
  102. //	BarMatrixType BarMatrix;
  103.  
  104. 	hello<0, Wrapper>(FooMatrix);	
  105. 	hello<1, Wrapper>(BarMatrix);	
  106.  
  107. 	return 0;
  108. }
Success #stdin #stdout 0s 3136KB
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stdout 
Standard output is empty
https://ideone.com/bNmt4j
language:
C++14 (gcc 8.3)
created:
9 years ago
visibility:
public

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