if_

template<template< class > typename Traits>

traits_check<Traits> kumi::if_ = {}

inlineconstexpr

Option restricting an identifier to accept values whose type satisfies the trait Traits.

Template Parameters

Traits

Traits that the parametrized identifier will use to validate its value.

#include <kumi/kumi.hpp>
#include <iostream>
 
using namespace kumi::literals;
 
template<typename T>
struct is_big : std::bool_constant<(sizeof(T) > 2)> {};
 
inline constexpr auto large_value = kumi::identifier("large"_id, kumi::if_<is_big>);
 
int main()
{
  std::cout << kumi::record{ large_value = 9.6 } << "\n";
}