reindex()

template<concepts::index_map auto Indexes, concepts::product_type T>

auto kumi::reindex ( T && t )

inlinenodiscardconstexpr

Reindex elements of a kumi::product_type.

This function does not participate in overload resolution if any Idx is outside [0, size_v<T>[.

Note

Nothing prevent the number of reordered index to be lesser or greater than t size or the fact they can appear multiple times.

Template Parameters

Indexes

A kumi::indexes representing the reindexed slot of the elements

Parameters

t	kumi::product_type to reindex

Returns

A potentially nested tuple following the Indexes order

Helper type

namespace kumi::result
{
  template<product_type T, index_map auto Idxs> struct reindex;
 
  template<product_type T, index_map auto Idxs>
  using reindex_t= typename reindex<T,Idxs>::type;
}

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

Example

#include <kumi/kumi.hpp>
#include <iostream>
 
int main()
{
  auto values = kumi::tuple { 1, 'a', 0.1 };
 
  constexpr auto basic = kumi::indexes(2,1,0);
  constexpr auto stack = kumi::indexes(2,1,0, kumi::indexes(0,1,2));
  constexpr auto pairs = kumi::indexes(kumi::indexes(0,0), kumi::indexes(1,1));
  
  std::cout << values << "\n";
  std::cout << kumi::reindex<basic>(values) << "\n";
  std::cout << kumi::reindex<stack>(values) << "\n";
  std::cout << kumi::reindex<pairs>(values) << "\n";
}

#include <kumi/kumi.hpp>
#include <iostream>
 
int main()
{
  using namespace kumi::literals;
  auto values = kumi::record { "a"_id = 1, "b"_id = 'a', "c"_id = 0.1 };
 
  constexpr auto basic = kumi::indexes(2,1,0);
  
  std::cout << values << "\n";
  std::cout << kumi::reindex<basic>(values) << "\n";
}