flatten()

template<concepts::product_type T>

auto kumi::flatten ( T && t )

inlinenodiscardconstexpr

Converts a product type of product types into a product type of all elements.

On record types, the names of the outer record are concatenated to the inner ones ultimately constructing names such as "outer.inner". If the input is a product type containing record types or vice versa only the inner types matching the outer semantic will be flattened. Thus a record inside a tuple will not be flattened.

Parameters

t	Product type to flatten

Returns

A product type composed of all elements of t flattened non-recursively

Helper type

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

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

Examples:

Tuple:

#include <kumi/kumi.hpp>
#include <iostream>
 
int main()
{
  auto nbrs       = kumi::tuple{1,2,3};
  auto more_nbrs  = kumi::tuple{0,nbrs,4};
  auto ltrs       = kumi::tuple{'a','b','c'};
 
  auto r = kumi::flatten( kumi::tuple{3.5,nbrs,'z',more_nbrs,5.35f,ltrs} );
  std::cout << r << "\n";
}

Record:

#include <kumi/kumi.hpp>
#include <iostream>
 
int main()
{
  using namespace kumi::literals;
  auto nbrs       = kumi::record{"a"_id = 1,"b"_id = 2,"c"_id = 3};
  auto more_nbrs  = kumi::record{"a"_id = 0,"b"_id = nbrs,"c"_id = 4};
  auto ltrs       = kumi::record{"a"_id = 'a',"b"_id = 'b',"c"_id = 'c'};
 
  auto r = kumi::flatten( kumi::record{"a"_id = 3.5,"b"_id = nbrs,"c"_id = 'z'
                          ,"d"_id = more_nbrs,"e"_id = 5.35f,"f"_id = ltrs} );
  std::cout << r << "\n";
}