locate

locate_t kumi::locate {}

inlineconstexprnodiscardnoexcept

Callable object Returning the index of a value which type satisfies a given predicate.

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

Header file

#include <kumi/algorithm/find.hpp>

Call Signature

template<product_type T, typename Predicate>
constexpr auto find(T && t, Predicate p) noexcept;

Parameters

• t: Product Type to process
• p: Unary predicate. p must return a value convertible to bool for every element of t.

Return value

• The integral index of the element inside t that matches the predicate, size_v<T> otherwise.

Examples

Tuple

#include <kumi/kumi.hpp>
#include <iostream>
#include <type_traits>
 
int main()
{
  auto t = kumi::tuple{1, 2., 0ULL, 3.f, 'z'};
 
  std::cout << std::boolalpha
            << kumi::locate( t, kumi::predicate<std::is_floating_point>() ) << "\n";
 
  std::cout << std::boolalpha << kumi::locate( t, [](auto e) { return e > 3; } ) << "\n";
}

Record

#include <kumi/kumi.hpp>
#include <iostream>
#include <type_traits>
 
int main()
{
  using namespace kumi::literals;
  auto r = kumi::record{"a"_id = 1, "b"_id = 2., "c"_id = 0ULL, "d"_id = 3.f, "e"_id = 'z'};
 
  std::cout << std::boolalpha
            << kumi::locate( r, kumi::predicate<std::is_floating_point>() ) << "\n";
 
  std::cout << std::boolalpha << kumi::locate( r, [](auto e) { return e > 3; } ) << "\n";
}