partition()

template<template< typename > typename Pred, concepts::product_type T>

auto kumi::partition ( T && t )

inlinenodiscardconstexprnoexcept

Partition a product type over a predicate.

Template Parameters

Pred	Compile-time predicate

Parameters

t	Product type to process

Returns

A tuple containing the product type of all values which types satisfies Pred in t and the product type of all values which types does not satisfy Pred.

On a record type, Pred is applied directly to the underlying elements of the fields.

Helper type

namespace kumi
{
  template<template<typename> typename Pred, kumi::product_type T> struct partition;
 
  template<template<typename> typename Pred, kumi::product_type T>
  using partition_t = typename partition<Pred, T>::type;
}

Computes the type returned by a call to kumi::partition.

Examples:

Tuple:

#include <kumi/kumi.hpp>
#include <type_traits>
#include <iostream>
 
int main()
{
  int     a = 4;
  double  b = 3.1415;
  float   c = 0.01f;
 
  auto original = kumi::tuple{a,&a,b,&b,c,&c,'z',nullptr};
  std::cout << original << "\n";
 
  std::cout << "Pointers first: " << kumi::partition<std::is_pointer>(original) << "\n";
  std::cout << "Real     first: " << kumi::partition<std::is_floating_point>(original) << "\n";
  std::cout << "nullptr  first: " << kumi::partition<std::is_null_pointer>(original) << "\n";
}

Record:

#include <kumi/kumi.hpp>
#include <type_traits>
#include <iostream>
 
int main()
{
  using namespace kumi::literals;
 
  int     a = 4;
  double  b = 3.1415;
  float   c = 0.01f;
 
  auto original = kumi::record{"a"_id = a,"b"_id = &a,"c"_id = b,"d"_id = &b,"e"_id = c,"f"_id = &c,"g"_id = 'z',"h"_id = nullptr};
  std::cout << original << "\n";
 
  std::cout << "Pointers first: " << kumi::partition<std::is_pointer>(original) << "\n";
  std::cout << "Real     first: " << kumi::partition<std::is_floating_point>(original) << "\n";
  std::cout << "nullptr  first: " << kumi::partition<std::is_null_pointer>(original) << "\n";
}