LeechCraft  0.6.70-9312-g4cc613a2df
Modular cross-platform feature rich live environment.
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visitor.h
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29 
30 #pragma once
31 
32 #include <boost/variant.hpp>
33 
34 namespace LeechCraft
35 {
36 namespace Util
37 {
38  namespace detail
39  {
40  template<typename Head, typename... Tail>
41  struct VisitorBase : std::decay_t<Head>, VisitorBase<Tail...>
42  {
43  using std::decay_t<Head>::operator();
44  using VisitorBase<Tail...>::operator();
45 
46  VisitorBase (Head&& head, Tail&&... tail)
47  : std::decay_t<Head> { std::forward<Head> (head) }
48  , VisitorBase<Tail...> { std::forward<Tail> (tail)... }
49  {
50  }
51  };
52 
53  template<typename Head>
54  struct VisitorBase<Head> : std::decay_t<Head>
55  {
56  using std::decay_t<Head>::operator();
57 
58  VisitorBase (Head&& head)
59  : std::decay_t<Head> { std::forward<Head> (head) }
60  {
61  }
62  };
63 
64  template<typename R, typename... Args>
65  struct Visitor : boost::static_visitor<R>, VisitorBase<Args...>
66  {
67  using VisitorBase<Args...>::VisitorBase;
68  };
69  }
70 
71  template<typename HeadVar, typename... TailVars, typename... Args>
72  auto Visit (const boost::variant<HeadVar, TailVars...>& v, Args&&... args) ->
73  decltype (detail::VisitorBase<Args...> { std::forward<Args> (args)... } (std::declval<HeadVar> ()))
74  {
75  using R_t = decltype (detail::VisitorBase<Args...> { std::forward<Args> (args)... } (std::declval<HeadVar> ()));
76 
77  return boost::apply_visitor (detail::Visitor<R_t, Args...> { std::forward<Args> (args)... }, v);
78  }
79 
80  template<typename T, typename... Args>
81  auto InvokeOn (T&& t, Args&&... args) -> decltype (detail::VisitorBase<Args...> { std::forward<Args> (args)... } (std::forward<T> (t)))
82  {
83  return detail::VisitorBase<Args...> { std::forward<Args> (args)... } (std::forward<T> (t));
84  }
85 }
86 }
LeechCraft::Util::Tail
constexpr List< T...> Tail(List< H, T...>)
Definition: typelist.h:44
LeechCraft::Util::InvokeOn
auto InvokeOn(T &&t, Args &&...args) -> decltype(detail::VisitorBase< Args...>
Definition: visitor.h:81
LeechCraft::Util::detail::VisitorBase::VisitorBase
VisitorBase(Head &&head, Tail &&...tail)
Definition: visitor.h:46
LeechCraft::Util::Visit
auto Visit(const boost::variant< HeadVar, TailVars...> &v, Args &&...args) -> decltype(detail::VisitorBase< Args...>
Definition: visitor.h:72