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C++14 helpers to call functor using args stored in a tuple, array or vector
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#include <iostream> | |
#include <array> | |
#include <vector> | |
#include <tuple> | |
#include <utility> | |
void printNumbers(int x, int y, int z) | |
{ | |
std::cout << x << std::endl; | |
std::cout << y << std::endl; | |
std::cout << z << std::endl; | |
} | |
template<std::size_t Index, typename TElementType, typename TContainer> | |
constexpr typename std::enable_if<std::is_rvalue_reference<TElementType>::value, TElementType>::type get_forward_impl(TContainer&& container) | |
{ | |
return std::move(std::get<Index>(container)); | |
} | |
template<std::size_t Index, typename TElementType, typename TContainer> | |
constexpr typename std::enable_if<!std::is_rvalue_reference<TElementType>::value, const TElementType&>::type get_forward_impl(TContainer&& container) | |
{ | |
return std::get<Index>(container); | |
} | |
template<std::size_t Index, typename... TTuple> | |
constexpr auto&& get_forward(const std::tuple<TTuple...>& tuple) | |
{ | |
using TElement = std::tuple_element_t<Index, std::tuple<TTuple...>>; | |
return get_forward_impl<Index, TElement>(tuple); | |
} | |
template<std::size_t Index, typename TArray, std::size_t N> | |
constexpr auto&& get_forward(const std::array<TArray, N>& array) | |
{ | |
return get_forward_impl<Index, TArray>(array); | |
} | |
template<std::size_t Index, typename TArray> | |
constexpr const auto& get_forward(const std::vector<TArray>& array) | |
{ | |
return array[Index]; | |
} | |
template<typename TFunctor, typename TContainer, std::size_t... Indices> | |
constexpr auto apply_sequence(TFunctor&& functor, TContainer&& container, std::index_sequence<Indices...>) | |
{ | |
return functor(get_forward<Indices>(std::forward<TContainer>(container))...); | |
} | |
template<typename TFunctor, typename... TTuple> | |
constexpr auto apply_tuple(TFunctor&& functor, const std::tuple<TTuple...>& tuple) | |
{ | |
return apply_sequence(std::forward<TFunctor>(functor), tuple, std::index_sequence_for<TTuple...>()); | |
} | |
template<typename TFunctor, typename TArg, std::size_t N> | |
constexpr auto apply_array(TFunctor&& functor, const std::array<TArg, N>& args) | |
{ | |
return apply_sequence(std::forward<TFunctor>(functor), args, std::make_index_sequence<N>()); | |
} | |
template<std::size_t N, typename TFunctor, typename TArg> | |
constexpr auto apply_vector(TFunctor&& functor, const std::vector<TArg>& args) | |
{ | |
return apply_sequence(std::forward<TFunctor>(functor), args, std::make_index_sequence<N>()); | |
} | |
int main(int argc, char* argv[]) | |
{ | |
std::array<int, 3> xxx { 2, 5, 77 }; | |
apply_array(printNumbers, xxx); | |
std::cout << "---------------" << std::endl; | |
std::vector<int> yyy { 3, 4, 5 }; | |
apply_vector<3>(printNumbers, yyy); | |
std::cout << "---------------" << std::endl; | |
std::tuple<int, int, int> zzz { 1, 2, 3 }; | |
apply_tuple(printNumbers, zzz); | |
return 0; | |
} |
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