map_index

map_index_t kumi::map_index {}

inlineconstexprnodiscard

Callable object applying the Callable object f on each product types elements and their indexes.

Applies the given function to all the product types passed as arguments along with their indexes and stores the result in another product type, keeping the original elements order.

Note

Does not participate in overload resolution if tuples' size are not equal or if f can't be called on each tuple's elements and their indexes.

Header file

#include <kumi/algorithm/map.hpp>

Call Signature

template<typename Function, product_type T, product_type... Ts>
constexpr auto map_index(Function && f, T && t, Ts &&... ts);

Parameters

• f: Callable object to apply
• t: Product Type to operate on
• ts: Other Product Types to operate on

Return value

• The product type matching the common_product_type of the input containing f calls results.

Helper type

    template<typename Function,
             kumi::concepts::product_type T,
             kumi::concepts::sized_product_type<kumi::size_v<T>>... Ts>
    struct map_index
    {
      using type = decltype(kumi::map_index(std::declval<Function>(), std::declval<T>(), std::declval<Ts>()...));
    };
 
    template<typename Function,
             kumi::concepts::product_type T,
             kumi::concepts::sized_product_type<kumi::size_v<T>>... Ts>
    using map_index_t = typename kumi::result::map_index<Function, T, Ts...>::type;
 

Computes the return type of a call to kumi::map_index

See also

kumi::map

kumi::map_field

Example

#include <kumi/kumi.hpp>
#include <iostream>
 
int main()
{
  auto lhs = kumi::tuple{1,2,3};
  auto rhs = kumi::tuple{2.4,4.6,6.8};
 
  auto res = kumi::map_index( [](auto i, auto l, auto r) { return 1000*(i+1)+(l*r); }
                            , lhs, rhs
                            );
 
  std::cout << res << "\n";
}