chunks()

template<std::size_t N, concepts::product_type T>

auto kumi::chunks ( T && t )

inlinenodiscardconstexpr

Creates a tuple of product types, each containing N consecutive elements from t. Chunks starts at 0 and advance by N element each time.

On record types, this function operates on elements as if they were ordered. The considered order is the order of declaration.

Template Parameters

N	Size of the chunks to generate

Parameters

t	the product type from which to extract the chunks

Returns

A tuple of product types, each containing N consecutive elements of t

Note

Chunks behaves like paving tiles: each inner product_type is a tile over t starting at index chunk_size * tile_number + 1. The last chunk will be smaller if the size of the product_type is not a multiple of the chunk size.

Helper type

namespace kumi::result
{
  template<std::size_t N, product_type T> struct chunks;
 
  template<std::size_t N, product_type T>
  using chunks_t = typename chunks<N, T>::type;
}

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

Examples:

Tuple:

#include <kumi/kumi.hpp>
#include <iostream>
 
int main()
{
  auto t = kumi::tuple{1, 'y', 3.f, short{55}, -8, 66., "Pete"};
    
  auto c = kumi::chunks<2>(t); 
  std::cout << "  Standard Chunks " << "\n";
  std::cout << c << "\n";
 
  kumi::for_each([&](auto tile)
  {
    get<0>(tile)++;
  },c);
  std::cout << t << "\n";
 
  auto c2 = kumi::chunks<2>(kumi::to_ref(t));
  std::cout << "  Chunks with references " << "\n";
  std::cout << c2 << "\n";
 
  kumi::for_each([&](auto tile)
  {
    get<0>(tile)++;
  },c2);
  std::cout << t << "\n";
}

Record:

#include <kumi/kumi.hpp>
#include <iostream>
 
int main()
{
  using namespace kumi::literals;
  auto t = kumi::record{"a"_id = 1, "b"_id = 'y', "c"_id = 3.f, "d"_id = short{55}
                      , "e"_id = -8, "f"_id = 66., "g"_id = "Pete"};
    
  auto c = kumi::chunks<2>(t); 
  std::cout << "  Standard Chunks " << "\n";
  std::cout << c << "\n";
 
  kumi::for_each([&](auto tile)
  {
    get<0>(kumi::values_of(tile))++;
  },c);
  std::cout << t << "\n";
 
  auto c2 = kumi::chunks<2>(kumi::to_ref(t));
  std::cout << "  Chunks with references " << "\n";
  std::cout << c2 << "\n";
 
  kumi::for_each([&](auto tile)
  {
    get<0>(kumi::values_of(tile))++;
  },c2);
  std::cout << t << "\n";
}