rotate_left()

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

auto kumi::rotate_left ( T && t )

constexpr

Rotates the element of a product type R positions to the left, wrapping around when getting to the beginning.

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

Template Parameters

R	Rotation factor

Parameters

t	Product type to rotate.

Returns

A product type equivalent to t with elements rotated R positions to the left.

Helper type

namespace kumi::result
{
  template<std::size_t R, product_type T> struct rotate_left;
 
  template<std::size_t R, product_type T>
  using rotate_left_t = typename rotate_left<R, T>::type;
}

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

Examples:

Tuple:

#include <kumi/kumi.hpp>
#include <iostream>
 
int main()
{
  auto values = kumi::tuple {'A','B','C','D','E','F'};
 
  std::cout << values << "\n";
  std::cout << kumi::rotate_left<1>(values) << "\n";
  std::cout << kumi::rotate_left<3>(values) << "\n";
}

Record:

#include <kumi/kumi.hpp>
#include <iostream>
 
int main()
{
  using namespace kumi::literals;
  auto values = kumi::record{"a"_id=1,"b"_id=2,"c"_id=3,"d"_id=4,"e"_id=5,"f"_id=6};
 
  std::cout << values << "\n";
  std::cout << kumi::rotate_left<1>(values) << "\n";
  std::cout << kumi::rotate_left<3>(values) << "\n";
}