reduce() [2/2]

template<monoid M, product_type T, typename Value >

constexpr auto kumi::reduce ( M &&  m, T &&  t, Value  init  )

inlineconstexpr

Performs a tree-like reduction of all elements of a product type.

Note

For associative operations, this produces the same result as a left or right fold, but have different intermediate evaluation order.

Parameters

m	Monoid callable function to apply
t	Product type to reduce
init	Optional initial value of the reduction.

Returns

The result of reducing t by recursively combining elements in a tree structure.

Helper type

namespace kumi::result
{
  template<monoid M, product_type T, typename Value> struct reduce;
 
  template<monoid M, product_type T, typename Value>
  using reduce_t = typename reduce<M,T,Value>::type;
}

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

Example

 
#include <kumi/kumi.hpp>
#include <iostream>
 
int main()
{
  auto t1 = kumi::tuple{14,short{7}, 255ULL};
  std::cout << kumi::reduce(kumi::function::bit_and, t1)        << "\n";
  std::cout << kumi::reduce(kumi::function::bit_and, t1, 65535) << "\n";
 
  auto t2 = kumi::tuple{1 ,short{8},' ', 4ULL};
  std::cout << kumi::reduce(kumi::function::bit_or, t2)         << "\n";
  std::cout << kumi::reduce(kumi::function::bit_or, t2, 0)      << "\n";
 
  auto t3 = kumi::tuple{3, short{23}, '\t'};
  std::cout << kumi::reduce(kumi::function::bit_xor, t3)        << "\n";
  std::cout << kumi::reduce(kumi::function::bit_xor, t3, 1)     << "\n";
 
  auto t4 = kumi::tuple{2.,5,short{3},'\4'};
  std::cout << kumi::reduce(kumi::function::multiplies, t4)     << "\n";
  std::cout << kumi::reduce(kumi::function::multiplies, t4, 1)  << "\n";
 
  auto t5 = kumi::tuple{2.,1,short{55},' '};
  std::cout << kumi::reduce(kumi::function::plus, t5)           << "\n";
  std::cout << kumi::reduce(kumi::function::plus, t5, 42)        << "\n";
}