meta::semiregular¶

Defined in header <mgs/meta/concepts/semiregular.hpp>.

template <typename T>
concept semiregular = meta::copyable<T> && meta::default_constructible<T>;

Pre-C++20 implementation of the std::semiregular concept.

Concept emulation¶

namespace mgs {
namespace meta {

template <typename T>
struct is_semiregular { /* ... */ };

template <typename T>
constexpr auto is_semiregular_v = is_semiregular<T>::value;

template <typename T,
          typename = std::enable_if_t<is_semiregular_v<T>>>
using semiregular = T;

} // namespace meta
} // namespace mgs

Example¶

#include <mgs/meta/concepts/semiregular.hpp>

using namespace mgs::meta;

// no equality operator
struct semiregular {};

static_assert(is_semiregular_v<std::vector<int>>, "");
static_assert(is_semiregular_v<int>, "");
static_assert(!is_semiregular_v<semiregular>, "");

See also¶