map_index()

template<concepts::product_type T, typename Function, concepts::sized_product_type< size_v< T > >... Ts>
requires (!concepts::record_type<T> && (!concepts::record_type<Ts> && ...))

auto kumi::map_index ( Function f, T && t0, Ts &&... others )

inlinenodiscardconstexpr

Applies the Callable object f on each tuples' elements and their indexes.

Applies the given function to all the tuples passed as arguments along with their indexes and stores the result in another tuple, 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.

Parameters

f	Callable function to apply
t0	Product type to operate on
others	Product types to operate on

Returns

The tuple of f calls results.

Helper type

namespace kumi::result
{
  template<typename Function, product_type T, product_type... Ts> struct map_index;
 
  template<typename Function, product_type T, product_type... Ts>
  using map_index_t = typename map_index<Function,T>::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";
}