Implementations of some type traits from C++17 and Lib Fundamentals v2 TS, and C++14-style type aliases for C++11.
template<bool B> tl::bool_constant = std::integral_constant<bool, B>
template<std::size_t N> tl::index_constant = std::integral_constant<std::size_t, N>
template<class... Cs> tl::conjunction
static constexpr bool value
The result of && ing together C::value for each C in Cs.
Like doing (Cs::value && ...) in C++17.
type = tl::bool_constant<value>
template<class... Cs> tl::disjunction
static constexpr bool value
The result of || ing together C::value for each C in Cs.
Like doing (Cs::value || ...) in C++17.
type = tl::bool_constant<value>
template<class B> tl::negation : tl::bool_constant<!B::value>
Negates a type trait result.
template<class...> tl::void_t = void
Turns any number of types into void.
This is useful as a metaprogramming trick.
template <template <class...> class Trait, class... Args>tl::is_detected = magic
Checks if Trait<Args...> is a valid specialization. Implements std::experimental::is_detected from Lib Fundamentals V2 TS. Useful for detecting the presence of a given type member. Example: :
template<class T>
using make_cute_t = decltype(std::declval<T>().make_cute());
template<class T>
using can_make_cute = tl::is_detected<make_cute_t, T>;
struct cat{ void make_cute(); };
struct abstract_concept_of_fear{};
static_assert(can_make_cute<cat>::value);
static_assert(!can_make_cute<abstract_concept_of_fear>::value);template <typename T> tl::safe_underlying_type_t = magic
Like std::underlying_type, but if T is not an enum then there's just no type member rather than being UB. Essentially implements P0340.
template <class T> tl::remove_cv_t = typename std::remove_cv<T>::type
template <class T> tl::remove_const_t = typename std::remove_const<T>::type
template <class T> tl::remove_volatile_t = typename std::remove_volatile<T>::type
template <class T> tl::add_cv_t = typename std::add_cv<T>::type
template <class T> tl::add_const_t = typename std::add_const<T>::type
template <class T> tl::add_volatile_t = typename std::add_volatile<T>::type
template <class T> tl::remove_reference_t = typename std::remove_reference<T>::type
template <class T> tl::add_lvalue_reference_t = typename std::add_lvalue_reference<T>::type
template <class T> tl::add_rvalue_reference_t = typename std::add_rvalue_reference<T>::type
template <class T> tl::remove_pointer_t = typename std::remove_pointer<T>::type
template <class T> tl::add_pointer_t = typename std::add_pointer<T>::type
template <class T> tl::make_signed_t = typename std::make_signed<T>::type
template <class T> tl::make_unsigned_t = typename std::make_unsigned<T>::type
template <class T> tl::remove_extent_t = typename std::remove_extent<T>::type
template <class T> tl::remove_all_extents_t = typename std::remove_all_extents<T>::type
template <std::size_t N, std::size_t AN> tl::aligned_storage_t = typename std::aligned_storage<N,A>::type
template <std::size_t N, class... Ts> tl::aligned_union_t = typename std::aligned_union<N,Ts...>::type
template <class T> tl::decay_t = typename std::decay<T>::type
template <bool E, class Tvoid> tl::enable_if_t = typename std::enable_if<E,T>::type
template <bool B, class T, class F> tl::conditional_t = typename std::conditional<B,T,F>::type
template <class... Ts> tl::common_type_t = typename std::common_type<Ts...>::type
template <class T> tl::underlying_type_t = typename std::underlying_type<T>::type
template <class T> tl::result_of_t = typename std::result_of<T>::type