Ignition Physics

API Reference

2.3.0
TemplateHelpers.hh
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17 
18 #ifndef IGNITION_PHYSICS_TEMPLATEHELPERS_HH_
19 #define IGNITION_PHYSICS_TEMPLATEHELPERS_HH_
20 
21 #include <type_traits>
22 
23 namespace ignition
24 {
25  namespace physics
26  {
28  struct Empty { };
29 
32  template <class... T> struct type { };
33 
36  template <typename...>
37  using void_t = void;
38 
57  template <typename To, typename From>
59 
60  template <typename To, typename From>
63  }
64 }
65 
81 #define IGN_PHYSICS_CREATE_SELECTOR(X) \
82  template<typename InFeature> \
83  struct Select ## X \
84  { \
85  template<typename F, typename PolicyT, typename FeaturesT, \
86  typename = ::ignition::physics::void_t<>> \
87  struct Implementation \
88  { \
89  using type = ::ignition::physics::Empty; \
90  }; \
91  \
92  template<typename F, typename PolicyT, typename FeaturesT> \
93  struct Implementation<F, PolicyT, FeaturesT, \
94  ::ignition::physics::void_t< \
95  typename F::template X <PolicyT, FeaturesT>>> \
96  { \
97  using type = typename F::template X <PolicyT, FeaturesT>; \
98  }; \
99  \
100  template <typename PolicyT, typename FeaturesT> \
101  using type = typename Implementation<InFeature, PolicyT, FeaturesT>::type; \
102  };
103 
104 #endif
Useful as a blank placeholder in template metaprogramming.
Definition: TemplateHelpers.hh:28
void void_t
Definition: TemplateHelpers.hh:37
Contains a static constexpr field named value which will be true if the type From has a const-quality...
Definition: TemplateHelpers.hh:58
This can be used to turn a type into a function argument, which is useful for template metaprogrammin...
Definition: TemplateHelpers.hh:32