kumi::common_product_type< Ts > Struct Template Reference

Extracts the common product_type of a parameter pack. More...

Detailed Description

template<typename... Ts>
struct kumi::common_product_type< Ts >

Extracts the common product_type of a parameter pack.

If all the types are record types then it returns an empty record type, otherwise returns an empty product type. As we are unable to properly compute the Least Restrictive Subtype of a pack this trait is specialized in the following way.

• If all input types are the same product_type, provide a type alias corresponding to it.
• If all input types are instance of the same template itself beeing a product_type, expose the template.
• If all types are kumi::concepts::product_type, use kumi::tuple as the alias.
• If all types are kumi::concepts::record_type, use kumi::record as the alias.

Note

It is used in algorithm taking multiple product types as input in order to determine the correct output type.

Template Parameters

Ts	The product types to access

Helper type

namespace kumi
{
  template<typename... Ts> using common_product_type_t = typename common_product_type<Ts...>::type;
}