contains()

template<concepts::product_type T, concepts::identifier ID>

bool kumi::contains ( T && t, ID const & id )

inlineconstexprnoexcept

Checks if a product type contains a given identifier.

Parameters

t	the product type to inspect.
id	Identifier to check

Returns

true if the t contains a field labeled with the id identifier, false otherwise.

Examples:

Tuple:

#include <kumi/kumi.hpp>
#include <iostream>
 
using namespace kumi::literals;
 
template<kumi::concepts::product_type T>
void check_contains(T const& t)
{
  if constexpr(contains(T{}, "value"_id))
    std::cout << "Correct product_type: " << get<"value"_id>(t) << '\n';
  else
    std::cout << "Incorrect product type\n";
}
 
int main()
{
  check_contains( kumi::tuple{"value"_id = 9  });
  check_contains( kumi::tuple{"malus"_id = 3.5});
  check_contains( kumi::tuple{"malus"_id = 6.5, "value"_id = 17} );
}

Record:

#include <kumi/kumi.hpp>
#include <iostream>
 
using namespace kumi::literals;
 
template<kumi::concepts::product_type T>
void check_contains(T const& t)
{
  if constexpr(contains(T{}, "value"_id))
    std::cout << "Correct product_type: " << get<"value"_id>(t) << '\n';
  else
    std::cout << "Incorrect product type\n";
}
 
int main()
{
  check_contains( kumi::record{"value"_id = 9  });
  check_contains( kumi::record{"malus"_id = 3.5});
  check_contains( kumi::record{"malus"_id = 6.5, "value"_id = 17} );
}