meta Namespace Reference

Tiny metaprogramming library. More...

Namespaces
namespace	extension
	Extend meta with your own datatypes.
namespace	lazy
	Lazy versions of meta actions.

Classes
struct	and_c
struct	bind_back
	An invocable that partially applies the invocable Fn by binding the arguments Us to the back of Fn. More...
struct	bind_front
	An invocable that partially applies the invocable Fn by binding the arguments Ts to the front of Fn. More...
struct	compose_
	Compose the Invocables Fns in the parameter pack Ts. More...
struct	compose_< Fn0 >
struct	compose_< Fn0, Fns... >
struct	defer
	A wrapper that defers the instantiation of a template C with type parameters Ts in a lambda or let expression. More...
struct	defer_i
	A wrapper that defers the instantiation of a template C with integral constant parameters Is in a lambda or let expression. More...
struct	flip
	An invocable that reverses the order of the first two arguments. More...
struct	id
	A trait that always returns its argument T. It is also an invocable that always returns T. More...
struct	integer_sequence
	A container for a sequence of compile-time integer constants. More...
struct	list
	A list of types. More...
struct	nil_
	An empty type. More...
struct	or_c
	Logically OR together all the Boolean parameters. More...
struct	quote
	Turn a template C into an invocable. More...
struct	quote_i
	Turn a template C taking literals of type T into a invocable. More...
struct	var
	For use when defining local variables in meta::let expressions. More...

Typedefs
using	_args = vararg< void >
using	_args_a = vararg< _a >
using	_args_b = vararg< _b >
using	_args_c = vararg< _c >
template<trait T>
using	_t = typename T::type
	Type alias for T::type.
template<list_like L, typename State , invocable Fn>
using	accumulate = fold< L, State, Fn >
	An alias for meta::fold. More...
template<typename T >
using	alignof_ = meta::size_t< alignof(T)>
	An alias that computes the alignment required for any instance of the type T. More...
template<list_like L, invocable Fn>
using	all_of = empty< find_if< L, not_fn< Fn > > >
	A Boolean integral constant wrapper around true if invoke<Fn, A>::value is true for all elements A in meta::list L; false, otherwise. More...
template<typename... Bs>
using	and_ = _t< detail::_and_< Bs... > >
	Logically AND together all the integral constant-wrapped Boolean parameters, with short-circuiting.
template<list_like L, invocable Fn>
using	any_of = not_< empty< find_if< L, Fn > > >
	A Boolean integral constant wrapper around true if invoke<Fn, A>::value is true for any element A in meta::list L; false, otherwise. More...
template<invocable Fn, typename L >
using	apply = _t< extension::apply< Fn, L > >
	Applies the invocable Fn using the types in the type list L as arguments.
template<typename Sequence >
using	as_list = _t< detail::as_list_< detail::uncvref_t< Sequence > > >
	Turn a type into an instance of meta::list in a way determined by meta::apply.
template<list_like L, integral N>
using	at = at_c< L, N::type::value >
	Return the N th element in the meta::list L. More...
template<list_like L, std::size_t N>
using	at_c = _t< detail::at_< L, N > >
	Return the N th element in the meta::list L. More...
template<list_like L>
using	back = _t< detail::back_< L > >
	Return the last element in meta::list L. More...
template<integral T, integral U>
using	bit_and = std::integral_constant< decltype(T::type::value &U::type::value), T::type::value &U::type::value >
	An integral constant wrapper around the result of bitwise-and'ing the two wrapped integers T::type::value and U::type::value.
template<integral T>
using	bit_not = std::integral_constant< decltype(~T::type::value), ~T::type::value >
	An integral constant wrapper around the result of bitwise-complementing the wrapped integer T::type::value.
template<integral T, integral U>
using	bit_or = std::integral_constant< decltype(T::type::value|U::type::value), T::type::value|U::type::value >
	An integral constant wrapper around the result of bitwise-or'ing the two wrapped integers T::type::value and U::type::value.
template<integral T, integral U>
using	bit_xor = std::integral_constant< decltype(T::type::value ^ U::type::value), T::type::value ^ U::type::value >
	An integral constant wrapper around the result of bitwise-exclusive-or'ing the two wrapped integers T::type::value and U::type::value.
template<bool B>
using	bool_ = std::integral_constant< bool, B >
	An integral constant wrapper for bool.
template<list_like ListOfLists>
using	cartesian_product = reverse_fold< ListOfLists, list< list<> >, quote_trait< detail::cartesian_product_fn > >
	Given a list of lists ListOfLists, return a new list of lists that is the Cartesian Product. Like the sequence function from the Haskell Prelude. More...
template<char Ch>
using	char_ = std::integral_constant< char, Ch >
	An integral constant wrapper for char.
template<typename... Fns>
using	compose = compose_< Fns... >
template<typename... Lists>
using	concat = concat_< Lists... >
template<list_like ... Ls>
using	concat_ = _t< detail::concat_< Ls... > >
	Concatenates several lists into a single list. More...
template<bool If, typename Then , typename Else = void>
using	conditional_t = typename detail::_cond< If >::template invoke< Then, Else >
	Select one type or another depending on a compile-time Boolean.
template<list_like L, typename T >
using	count = _t< detail::count_< L, T > >
	Count the number of times a type T appears in the list L. More...
template<list_like L, invocable Fn>
using	count_if = _t< detail::count_if_< L, Fn > >
	Count the number of times the predicate Fn evaluates to true for all the elements in the list L. More...
template<invocable Fn, invocable Q = quote<list>>
using	curry = compose< Fn, Q >
	An invocable that takes a bunch of arguments, bundles them into a type list, and then calls the invocable Fn with the type list Q.
template<integral T>
using	dec = std::integral_constant< decltype(T::type::value - 1), T::type::value - 1 >
	An integral constant wrapper around the result of decrementing the wrapped integer T::type::value.
template<template< typename... > class C, typename... Ts>
using	defer_trait = defer< detail::_t_t, detail::defer_< C, Ts... > >
	A wrapper that defers the instantiation of a trait C with type parameters Ts in a lambda or let expression. More...
template<typename T , template< T... > class C, T... Is>
using	defer_trait_i = defer< detail::_t_t, detail::defer_i_< T, C, Is... > >
	A wrapper that defers the instantiation of a trait C with integral constant parameters Is in a lambda or let expression. More...
template<integral T, integral U>
using	divides = std::integral_constant< decltype(T::type::value/U::type::value), T::type::value/U::type::value >
	An integral constant wrapper around the result of dividing the two wrapped integers T::type::value and U::type::value.
template<list_like L, integral N>
using	drop = drop_c< L, N::type::value >
	Return a new meta::list by removing the first N elements from L. More...
template<list_like L, std::size_t N>
using	drop_c = _t< detail::drop_< L, N > >
	Return a new meta::list by removing the first N elements from L. More...
template<list_like L>
using	empty = bool_< 0==size< L >::type::value >
	An Boolean integral constant wrapper around true if L is an empty type list; false, otherwise. More...
template<integral T, integral U>
using	equal_to = bool_< T::type::value==U::type::value >
	A Boolean integral constant wrapper around the result of comparing T::type::value and U::type::value for equality.
template<typename L , typename Pred >
using	filter = join< transform< L, detail::filter_< Pred > > >
	Returns a new meta::list where only those elements of L that satisfy the Callable Pred such that invoke<Pred,A>::value is true are present. That is, those elements that don't satisfy the Pred are "removed". More...
template<list_like L, typename T >
using	find = drop< L, min< find_index< L, T >, size< L > > >
	Return the tail of the list L starting at the first occurrence of T, if any such element exists; the empty list, otherwise. More...
template<list_like L, invocable Fn>
using	find_if = _t< detail::find_if_< L, Fn > >
	Return the tail of the list L starting at the first element A such that invoke<Fn, A>::value is true, if any such element exists; the empty list, otherwise. More...
template<list_like L, typename T >
using	find_index = _t< detail::find_index_< L, T > >
	Finds the index of the first occurrence of the type T within the list L. Returns #meta::npos if the type T was not found. More...
template<typename Pair >
using	first = front< Pair >
	Retrieve the first element of the pair Pair.
template<list_like L, typename State , invocable Fn>
using	fold = _t< detail::fold_< L, State, Fn > >
	Return a new meta::list constructed by doing a left fold of the list L using binary invocable Fn and initial state State. That is, the State(N) for the list element A(N) is computed by Fn(State(N-1), A(N)) -> State(N). More...
template<list_like L>
using	front = _t< detail::front_< L > >
	Return the first element in meta::list L. More...
template<integral T, integral U>
using	greater = bool_<(T::type::value > U::type::value)>
	A Boolean integral constant wrapper around true if T::type::value is greater than U::type::value; false, otherwise.
template<integral T, integral U>
using	greater_equal = bool_<(T::type::value >=U::type::value)>
	A Boolean integral constant wrapper around true if T::type::value is greater than or equal to U::type::value; false, otherwise.
template<typename T >
using	id_t = _t< id< T > >
	An alias for type T. Useful in non-deduced contexts.
template<typename... Args>
using	if_ = _t< detail::_if_< Args... > >
	Select one type or another depending on a compile-time Boolean.
template<bool If, typename... Args>
using	if_c = _t< detail::_if_< bool_< If >, Args... > >
	Select one type or another depending on a compile-time Boolean.
template<list_like L, typename T >
using	in = not_< empty< find< L, T > > >
	A Boolean integral constant wrapper around true if there is at least one occurrence of T in L. More...
template<integral T>
using	inc = std::integral_constant< decltype(T::type::value+1), T::type::value+1 >
	An integral constant wrapper around the result of incrementing the wrapped integer T::type::value.
template<std::size_t... Is>
using	index_sequence = integer_sequence< std::size_t, Is... >
	A container for a sequence of compile-time integer constants of type std::size_t.
template<list_like L>
using	inherit = meta::_t< detail::inherit_< L > >
	A type that inherits from all the types in the list. More...
template<int I>
using	int_ = std::integral_constant< int, I >
	An integral constant wrapper for int.
template<typename T , T From, T To>
using	integer_range = _t< detail::coerce_indices_< T, From, make_index_sequence< detail::range_distance_(From, To)> > >
	Makes the integer sequence [From, To). More...
template<invocable Fn, typename... Args>
using	invoke = typename Fn::template invoke< Args... >
	Evaluate the invocable Fn with the arguments Args.
template<typename T , template< typename... > class C>
using	is = _t< detail::is_< T, C > >
	is More...
template<typename T >
using	is_callable = _t< detail::is_callable_< T > >
	An alias for std::true_type if T::invoke exists and names a class template or alias template; otherwise, it's an alias for std::false_type.
template<typename T >
using	is_trait = _t< detail::is_trait_< T > >
template<typename T >
using	is_valid = detail::is_valid_< T >
	For testing whether a deferred computation will succeed in a let or a lambda.
template<list_like ListOfLists>
using	join = apply< quote< concat >, ListOfLists >
	Joins a list of lists into a single list. More...
template<typename... Ts>
using	lambda = detail::lambda_< list< Ts... > >
	For creating anonymous Invocables. More...
template<integral T, integral U>
using	less = bool_<(T::type::value< U::type::value)>
	A Boolean integral constant wrapper around true if T::type::value is less than U::type::value; false, otherwise.
template<integral T, integral U>
using	less_equal = bool_<(T::type::value<=U::type::value)>
	A Boolean integral constant wrapper around true if T::type::value is less than or equal to U::type::value; false, otherwise.
template<typename... As>
using	let = _t< _t< detail::let_< As... > > >
	A lexically scoped expression with local variables. More...
template<std::size_t N>
using	make_index_sequence = _t< detail::make_indices_< N, index_sequence< 0 >, detail::strategy_(1, N)> >
	Generate index_sequence containing integer constants [0,1,2,...,N-1]. More...
template<typename T , T N>
using	make_integer_sequence = _t< detail::coerce_indices_< T, 0, make_index_sequence< static_cast< std::size_t >(N)> > >
	Generate integer_sequence containing integer constants [0,1,2,...,N-1]. More...
template<typename... Ts>
using	max = max_< Ts... >
template<integral ... Ts>
using	max_ = fold< pop_front< list< Ts... > >, front< list< Ts... > >, quote< detail::max_ > >
	An integral constant wrapper around the maximum of Ts::type::value...
template<typename... Ts>
using	min = min_< Ts... >
template<integral ... Ts>
using	min_ = fold< pop_front< list< Ts... > >, front< list< Ts... > >, quote< detail::min_ > >
	An integral constant wrapper around the minimum of Ts::type::value...
template<integral T, integral U>
using	minus = std::integral_constant< decltype(T::type::value - U::type::value), T::type::value - U::type::value >
	An integral constant wrapper around the result of subtracting the two wrapped integers T::type::value and U::type::value.
template<integral T, integral U>
using	modulus = std::integral_constant< decltype(T::type::value % U::type::value), T::type::value % U::type::value >
	An integral constant wrapper around the remainder of dividing the two wrapped integers T::type::value and U::type::value.
template<integral T, integral U>
using	multiplies = std::integral_constant< decltype(T::type::value *U::type::value), T::type::value *U::type::value >
	An integral constant wrapper around the result of multiplying the two wrapped integers T::type::value and U::type::value.
template<integral T>
using	negate = std::integral_constant< decltype(-T::type::value), -T::type::value >
	An integral constant wrapper around the result of negating the wrapped integer T::type::value.
template<list_like L, invocable Fn>
using	none_of = empty< find_if< L, Fn > >
	A Boolean integral constant wrapper around true if invoke<Fn, A>::value is false for all elements A in meta::list L; false, otherwise. More...
template<integral B>
using	not_ = not_c< B::type::value >
	Logically negate the integral constant-wrapped Boolean parameter.
template<bool B>
using	not_c = bool_<!B >
	Logically negate the Boolean parameter.
template<integral T, integral U>
using	not_equal_to = bool_< T::type::value !=U::type::value >
	A Boolean integral constant wrapper around the result of comparing T::type::value and U::type::value for inequality.
template<invocable Fn>
using	not_fn = compose< quote< not_ >, Fn >
	Logically negate the result of invocable Fn.
using	npos = meta::size_t< std::size_t(-1)>
	A special value used to indicate no matches. It equals the maximum value representable by std::size_t.
template<typename... Fns>
using	on = on_< Fns... >
template<invocable ... Fns>
using	on_ = detail::on_< Fns... >
	Use as on<Fn, Gs...>. Creates an invocable that applies invocable Fn to the result of applying invocable compose<Gs...> to all the arguments.
template<typename... Bs>
using	or_ = _t< detail::_or_< Bs... > >
	Logically OR together all the integral constant-wrapped Boolean parameters, with short-circuiting.
template<typename F , typename S >
using	pair = list< F, S >
	A list with exactly two elements.
template<list_like L, invocable Fn>
using	partition = fold< L, pair< list<>, list<> >, detail::partition_< Fn > >
	Returns a pair of lists, where the elements of L that satisfy the invocable Fn such that invoke<Fn,A>::value is true are present in the first list and the rest are in the second. More...
template<integral T, integral U>
using	plus = std::integral_constant< decltype(T::type::value+U::type::value), T::type::value+U::type::value >
	An integral constant wrapper around the result of adding the two wrapped integers T::type::value and U::type::value.
template<list_like L>
using	pop_front = _t< detail::pop_front_< L > >
	Return a new meta::list by removing the first element from the front of L. More...
template<typename T >
using	protect = detail::protect_< T >
	For preventing the evaluation of a nested defered computation in a let or lambda expression.
template<list_like L, typename... Ts>
using	push_back = apply< bind_back< quote< list >, Ts... >, L >
	Return a new meta::list by adding the element T to the back of L. More...
template<list_like L, typename... Ts>
using	push_front = apply< bind_front< quote< list >, Ts... >, L >
	Return a new meta::list by adding the element T to the front of L. More...
template<template< typename... > class C>
using	quote_trait = compose< quote< _t >, quote< C > >
	Turn a trait template C into an invocable. More...
template<typename T , template< T... > class C>
using	quote_trait_i = compose< quote< _t >, quote_i< T, C > >
	Turn a trait template C taking literals of type T into an invocable.
template<integral N, typename T = void>
using	repeat_n = repeat_n_c< N::type::value, T >
	Generate list<T,T,T...T> of size N arguments. More...
template<std::size_t N, typename T = void>
using	repeat_n_c = _t< detail::repeat_n_c_< T, make_index_sequence< N > > >
	Generate list<T,T,T...T> of size N arguments. More...
template<list_like L, typename T , typename U >
using	replace = _t< detail::replace_< L, T, U > >
	Return a new meta::list where all instances of type T have been replaced with U. More...
template<list_like L, typename C , typename U >
using	replace_if = _t< detail::replace_if_< L, C, U > >
	Return a new meta::list where all elements A of the list L for which invoke<C,A>::value is true have been replaced with U. More...
template<list_like L>
using	reverse = _t< detail::reverse_< L > >
	Return a new meta::list by reversing the elements in the list L. More...
template<list_like L, typename T >
using	reverse_find = drop< L, min< reverse_find_index< L, T >, size< L > > >
	Return the tail of the list L starting at the last occurrence of T, if any such element exists; the empty list, otherwise. More...
template<list_like L, invocable Fn>
using	reverse_find_if = _t< detail::reverse_find_if_< L, Fn > >
	Return the tail of the list L starting at the last element A such that invoke<Fn, A>::value is true, if any such element exists; the empty list, otherwise. More...
template<list_like L, typename T >
using	reverse_find_index = _t< detail::reverse_find_index_< L, T > >
	Finds the index of the last occurrence of the type T within the list L. Returns #meta::npos if the type T was not found. More...
template<list_like L, typename State , invocable Fn>
using	reverse_fold = _t< detail::reverse_fold_< L, State, Fn > >
	Return a new meta::list constructed by doing a right fold of the list L using binary invocable Fn and initial state State. That is, the State(N) for the list element A(N) is computed by Fn(A(N), State(N+1)) -> State(N). More...
template<typename Pair >
using	second = front< pop_front< Pair > >
	Retrieve the first element of the pair Pair.
template<list_like L>
using	size = meta::size_t< L::size()>
	An integral constant wrapper that is the size of the meta::list L.
template<std::size_t N>
using	size_t = std::integral_constant< std::size_t, N >
	An integral constant wrapper for std::size_t.
template<typename T >
using	sizeof_ = meta::size_t< sizeof(T)>
	An alias that computes the size of the type T. More...
template<list_like L, invocable Fn>
using	sort = _t< detail::sort_< L, Fn > >
	Return a new meta::list that is sorted according to invocable predicate Fn. More...
template<typename... Bs>
using	strict_and = strict_and_< Bs... >
template<integral ... Bs>
using	strict_and_ = and_c< Bs::type::value... >
	Logically AND together all the integral constant-wrapped Boolean parameters, without short-circuiting.
template<typename... Bs>
using	strict_or = strict_or_< Bs... >
template<integral ... Bs>
using	strict_or_ = or_c< Bs::type::value... >
	Logically OR together all the integral constant-wrapped Boolean parameters, without short-circuiting.
template<typename... Args>
using	transform = _t< detail::transform_< Args... > >
	Return a new meta::list constructed by transforming all the elements in L with the unary invocable Fn. transform can also be called with two lists of the same length and a binary invocable, in which case it returns a new list constructed with the results of calling Fn with each element in the lists, pairwise. More...
template<list_like ListOfLists>
using	transpose = fold< ListOfLists, repeat_n< size< front< ListOfLists > >, list<> >, bind_back< quote< transform >, quote< push_back > > >
	Given a list of lists of types ListOfLists, transpose the elements from the lists. More...
template<invocable Fn>
using	uncurry = bind_front< quote< apply >, Fn >
	An invocable that takes a type list, unpacks the types, and then calls the invocable Fn with the types.
template<list_like L>
using	unique = fold< L, list<>, quote_trait< detail::insert_back_ > >
	Return a new meta::list where all duplicate elements have been removed. More...
template<typename T >
using	vararg = detail::vararg_< T >
	For defining variadic placeholders.
template<typename... >
using	void_ = void
	An alias for void.
template<list_like ListOfLists>
using	zip = transpose< ListOfLists >
	Given a list of lists of types ListOfLists, construct a new list by grouping the elements from the lists pairwise into meta::lists. More...
template<invocable Fn, list_like ListOfLists>
using	zip_with = transform< transpose< ListOfLists >, uncurry< Fn > >
	Given a list of lists of types ListOfLists and an invocable Fn, construct a new list by calling Fn with the elements from the lists pairwise. More...

Functions
template<char... Chs>
constexpr fold< list< char_< Chs >... >, meta::size_t< 0 >, quote< detail::atoi_ > >	operator""_z ()
	A user-defined literal that generates objects of type meta::size_t.

Variables
template<integral T>
constexpr T::type::value_type	_v = T::type::value
	Variable alias for T::type::value. More...
constexpr auto &&	for_each = detail::static_const<detail::for_each_fn>::value
	for_each(List, UnaryFunction) calls the UnaryFunction for each argument in the List.
template<typename , template< typename... > class>
constexpr bool	is_v = false
	is_v Test whether a type T is an instantiation of class template C.
template<typename... Ts, template< typename... > class C>
constexpr bool	is_v< C< Ts... >, C > = true

Detailed Description

Tiny metaprogramming library.