Provides seqan3::type_list and metaprogramming utilities for working on type lists.
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template<typename... pack1_t, typename... pack2_t, typename... more_lists_t> auto seqan3::list_traits::detail::concat (type_list < pack1_t... >, type_list < pack2_t... >, more_lists_t...) Implementation for seqan3::list_traits::concat [overload for more than two lists]. template<typename... pack_t> pack_traits::drop_front < pack_t... > seqan3::list_traits::detail::drop_front (type_list < pack_t... >) Implementation for seqan3::list_traits::drop_front . template<size_t count, typename t > auto seqan3::list_traits::detail::repeat () Implementation for seqan3::list_traits::repeat . template<typename replace_t , ptrdiff_t idx, typename... pack_t> pack_traits::replace_at < replace_t , idx , pack_t... > seqan3::list_traits::detail::replace_at (type_list < pack_t... >) Implementation for seqan3::list_traits::replace_at . template<ptrdiff_t idx, typename... pack1_t> pack_traits::split_after < idx , pack1_t... > seqan3::list_traits::detail::split_after (type_list < pack1_t... >) Implementation for seqan3::list_traits::split_after .
template<typename... lists_t> using seqan3::list_traits::concat = decltype (detail::concat(lists_t {}...)) Join two seqan3::type_list s into one. template<typename list_t > using seqan3::list_traits::drop_front = decltype (detail::drop_front(list_t {})) Return a seqan3::type_list of all the types in the type list, except the first. template<ptrdiff_t i, typename list_t > using seqan3::list_traits::take = typename decltype (detail::split_after < i >(list_t {}))::first_type Return a seqan3::type_list of the first n types in the input type list. template<ptrdiff_t i, typename list_t > using seqan3::list_traits::drop = typename decltype (detail::split_after < i >(list_t {}))::second_type Return a seqan3::type_list of the types in the input type list, except the first n. template<ptrdiff_t i, typename list_t > using seqan3::list_traits::take_last = drop < size< list_t > - i , list_t > Return a seqan3::type_list of the last n types in the input type list. template<ptrdiff_t i, typename list_t > using seqan3::list_traits::drop_last = take < size< list_t > - i , list_t > Return a seqan3::type_list of the types the input type list, except the last n. template<ptrdiff_t i, typename list_t > using seqan3::list_traits::split_after = decltype (detail::split_after< i >(list_t {})) Split a seqan3::type_list into two parts returned as a pair of seqan3::type_list . template<template < typename > typename trait_t, typename list_t > using seqan3::list_traits::transform = decltype (detail::transform< trait_t >(list_t {})) Apply a transformation trait to every type in the list and return a seqan3::type_list of the results. template<typename replace_t , std::ptrdiff_t i, typename list_t > using seqan3::list_traits::replace_at = decltype (detail::replace_at< replace_t , i >(list_t {})) Replace the type at the given index with the given type. template<size_t count, typename t > using seqan3::list_traits::repeat = decltype (detail::repeat< count, t >()) Create a type list with the given type repeated count times..
Provides seqan3::type_list and metaprogramming utilities for working on type lists.
See also Utility All traits on type lists are defined in the header <seqan3/utility/type_list/traits.hpp >.
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Return the type at given index from the type list.
Template Parameters
idx The index; must be smaller than the size of the type list. list_t The type_list .
Negative indexes are supported (e.g. at<-1, type_list <int, double, bool &>> is bool &).
(Compile-time) Complexity
Number of template instantiations: O(n)
Other operations: O(n)
int main()
{
static_assert (std::same_as<float, seqan3::list_traits::at<1, list_t>>);
}
A "pretty printer" for most SeqAn data structures and related types.
Definition debug_stream_type.hpp:79
typename decltype(detail::at< idx >(list_t{}))::type at
Return the type at given index from the type list.
Definition type_list/traits.hpp:276
Provides traits for seqan3::type_list.
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Return the last type from the type list.
Template Parameters
(Compile-time) Complexity
Number of template instantiations: O(n) (possibly O(1))
Other operations: O(1)
Notably faster than seqan3::pack_traits::at <size<pack...> - 1, pack...>
int main()
{
static_assert (std::same_as<float, seqan3::list_traits::back<list_t>>);
}
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Join two seqan3::type_list s into one.
Template Parameters
list1_t The first (input) type list. list2_t The second (input) type list.
(Compile-time) Complexity
Number of template instantiations: O(n) in the number of type lists
Other operations: O(n) in the number of type lists
Complexity is independent of the number of types in each list.
int main()
{
static_assert (std::same_as<seqan3::list_traits::concat<list_t, list_t2, list_t3>,
}
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Return a seqan3::type_list of the types in the input type list, except the first n.
Template Parameters
i The amount to drop; must be >= 0 and <= the size of the input type list. list_t The (input) type list.
(Compile-time) Complexity
Number of template instantiations: O(n)
Other operations: O(n)
int main()
{
}
typename decltype(detail::split_after< i >(list_t{}))::second_type drop
Return a seqan3::type_list of the types in the input type list, except the first n.
Definition type_list/traits.hpp:392
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Return a seqan3::type_list of all the types in the type list, except the first.
Template Parameters
list_t The (input) type list.
(Compile-time) Complexity
Number of template instantiations: O(1)
Other operations: O(1)
int main()
{
}
decltype(detail::drop_front(list_t{})) drop_front
Return a seqan3::type_list of all the types in the type list, except the first.
Definition type_list/traits.hpp:356
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Return a seqan3::type_list of the types the input type list, except the last n.
Template Parameters
i The amount to drop; must be >= 0 and <= the size of the input type list. list_t The (input) type list.
(Compile-time) Complexity
Number of template instantiations: O(n)
Other operations: O(n)
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Return the first type from the type list.
Template Parameters
(Compile-time) Complexity
Number of template instantiations: O(1)
Other operations: O(1)
int main()
{
static_assert (std::same_as<int, seqan3::list_traits::front<list_t>>);
}
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Create a type list with the given type repeated count times..
Template Parameters
count The number of repititions. t The type to repeat
(Compile-time) Complexity
Number of template instantiations: O(n)
Other operations: O(n)
However, with a constant of 0.2, e.g. repeat<10,int> results in 2-3 instantiations.
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Replace the type at the given index with the given type.
Template Parameters
replace_t The type to replace the old type with. i The index of the type to be replaced. list_t The (input) type list.
(Compile-time) Complexity
Number of template instantiations: O(n)
Other operations: O(n)
int main()
{
static_assert (
}
decltype(detail::replace_at< replace_t, i >(list_t{})) replace_at
Replace the type at the given index with the given type.
Definition type_list/traits.hpp:486
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Split a seqan3::type_list into two parts returned as a pair of seqan3::type_list .
Template Parameters
i The number of elements after which to split; must be >= 0 and <= the size of the input type list. list_t The (input) type list.
(Compile-time) Complexity
Number of template instantiations: O(n)
Other operations: O(n)
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Return a seqan3::type_list of the first n types in the input type list.
Template Parameters
i The target size; must be >= 0 and <= the size of the input type list. list_t The (input) type list.
(Compile-time) Complexity
Number of template instantiations: O(n)
Other operations: O(n)
int main()
{
}
typename decltype(detail::split_after< i >(list_t{}))::first_type take
Return a seqan3::type_list of the first n types in the input type list.
Definition type_list/traits.hpp:374
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Return a seqan3::type_list of the last n types in the input type list.
Template Parameters
i The target size; must be >= 0 and <= the size of the input type list. list_t The (input) type list.
(Compile-time) Complexity
Number of template instantiations: O(n)
Other operations: O(n)
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Apply a transformation trait to every type in the list and return a seqan3::type_list of the results.
Template Parameters
trait_t The trait to transform, must be an alias template , e.g. a transformation trait shortcut. list_t The (input) type list.
The transformation trait given as first argument must be an alias template, e.g. std::type_identity_t , not std::type_identity . The alias must take exactly one argument and be defined for all types in the input list.
(Compile-time) Complexity
Number of template instantiations: O(n)
Other operations: O(n)
int main()
{
static_assert (std::same_as<seqan3::list_traits::transform<std::ranges::range_reference_t, list_t>,
}
Provides various transformation traits used by the range module.
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auto seqan3::list_traits::detail::concat (
type_list < pack1_t... > ,
type_list < pack2_t... > ,
more_lists_t...
)
no-api
Implementation for seqan3::list_traits::concat [overload for more than two lists].
Template Parameters
pack1_t Types in the first type list. pack2_t Types in the second type list. more_lists_t The remaining type lists.
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auto seqan3::list_traits::detail::repeat (
)
no-api
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Implementation for seqan3::list_traits::replace_at .
Template Parameters
replace_t The type replacing the old one. idx The index of the type to replace. pack_t Types in the type list to be modified.
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Implementation for seqan3::list_traits::concat .
Template Parameters
pack1_t Types in the first type list. pack2_t Types in the second type list.
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Whether a type occurs in a type list or not.
Template Parameters
query_t The type you are searching for. pack_t The type pack.
Returns true or false.(Compile-time) Complexity
Number of template instantiations: O(1)
Other operations: O(n), possibly == i, where i is the index of the first occurrence
int main()
{
static_assert (seqan3::pack_traits::find<double, int, float, bool> == -1);
static_assert (seqan3::pack_traits::find<bool, int, float, bool> == 2);
}
Provides various traits for template packs.
int main()
{
static_assert (seqan3::list_traits::contains<double, list_t> == false );
static_assert (seqan3::list_traits::contains<float, list_t> == true );
}
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Count the occurrences of a type in a type list.
Template Parameters
query_t The type you are searching for. pack_t The type pack.
Returns The number of occurrences of the query_t in pack_t. (Compile-time) Complexity
Number of template instantiations: O(1)
Other operations: O(n)
int main()
{
static_assert (seqan3::pack_traits::count<int, int, float, bool, int> == 2);
}
int main()
{
static_assert (seqan3::list_traits::count<int, list_t> == 2);
}
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Initial value: =
constexpr ptrdiff_t find()
Implementation for seqan3::pack_traits::find.
Definition type_pack/traits.hpp:31
Get the index of the first occurrence of a type in a type list.
Template Parameters
query_t The type you are searching for. pack_t The type pack.
Returns The position of the first occurrence of query_t in pack_t or -1 if it is not contained. (Compile-time) Complexity
Number of template instantiations: O(1)
Other operations: O(n), possibly == i, where i is the return value
int main()
{
static_assert (seqan3::pack_traits::find<double, int, float, bool> == -1);
static_assert (seqan3::pack_traits::find<bool, int, float, bool> == 2);
}
int main()
{
static_assert (seqan3::list_traits::find<double, list_t> == -1);
static_assert (seqan3::list_traits::find<bool, list_t> == 2);
}
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Initial value: =
constexpr ptrdiff_t find_if()
Implementation for seqan3::pack_traits::find_if.
Definition type_pack/traits.hpp:44
Get the index of the first type in a type list that satisfies the given predicate.
Template Parameters
pred_t The predicate that is being evaluated (a class template). pack_t The type pack.
Returns The index or -1 if no types match. Note that the predicate must be given as a type template (variable templates cannot be passed as template arguments unfortunately). This means e.g. find_if<std::is_integral , float, double, int, float> (not std::is_integral_v
(Compile-time) Complexity
Number of template instantiations: O(n), possibly == i, where i is the return value
Other operations: O(n), possibly == i, where i is the return value
Only the predicate is instantiated.
int main()
{
static_assert (seqan3::pack_traits::find_if<std::is_pointer, int, float, double> == -1);
static_assert (seqan3::pack_traits::find_if<std::is_integral, int, float, double> == 0);
}
int main()
{
static_assert (seqan3::list_traits::find_if<std::is_pointer, list_t> == -1);
static_assert (seqan3::list_traits::find_if<std::is_integral, list_t> == 0);
}
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template<typename... pack_t>
The size of a type list.
Template Parameters
Returns sizeof...(pack_t)(Compile-time) Complexity
Number of template instantiations: O(1)
Other operations: O(1)
int main()
{
static_assert (seqan3::pack_traits::size<int, float, bool, int> == 4);
}
int main()
{
static_assert (seqan3::list_traits::size<list_t> == 4);
}
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Implementation for seqan3::list_traits::transform .
Template Parameters
trait_t The trait to transform, must be an alias template , e.g. a transformation trait shortcut. pack_t Types in the type list.
Collaboration diagram for Type List:
1.9.8