pop_back()

template<concepts::product_type T>

auto kumi::pop_back ( T && t )

inlinenodiscardconstexpr

Remove the last (if any) element of a kumi::product_type.

Parameters

t	Base product type

Returns

A product type composed of all elements of t except its last. Has no effect on empty product types.

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

Helper type

namespace kumi::result
{
  template<product_type T> struct pop_back;
 
  template<product_type T>
  using pop_back_t = typename pop_back<T>::type;
}

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

Examples:

Tuple:

#include <kumi/kumi.hpp>
#include <iostream>
 
int main()
{
  std::cout << kumi::pop_back( kumi::tuple{} )  << "\n";
 
  kumi::tuple t{1,2.,3.4f};
  std::cout << t                    << "\n";
  std::cout << kumi::pop_back(t)   << "\n";
}

Record:

#include <kumi/kumi.hpp>
#include <iostream>
 
int main()
{
  using namespace kumi::literals;
  std::cout << kumi::pop_back( kumi::record{} )  << "\n";
 
  kumi::record r{"a"_id = 1,"b"_id = 2.,"c"_id = 3.4f};
  std::cout << r                    << "\n";
  std::cout << kumi::pop_back(r)   << "\n";
}