filter()

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

constexpr auto kumi::filter ( T &&  t )

inlineconstexprnoexcept

Filters a product type over a predicate.

Template Parameters

Pred	Compile-time predicate

Parameters

t	Product type to process

Returns

A Product type containing all values which types satisfies Pred.

Helper type

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

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

Example:

 
#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 : " << kumi::filter<std::is_pointer>(original) << "\n";
  std::cout << "Real     : " << kumi::filter<std::is_floating_point>(original) << "\n";
  std::cout << "nullptr  : " << kumi::filter<std::is_null_pointer>(original) << "\n";
}

 
#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"_f=a,"b"_f=&a,"c"_f=b,"d"_f=&b,"e"_f=c,"f"_f=&c,"g"_f='z',"h"_f=nullptr};
  std::cout << original << "\n";
 
  std::cout << "Pointers : " << kumi::filter<std::is_pointer>(original) << "\n";
  std::cout << "Real     : " << kumi::filter<std::is_floating_point>(original) << "\n";
  std::cout << "nullptr  : " << kumi::filter<std::is_null_pointer>(original) << "\n";
}