seqan3::pack_traits Namespace Reference

Namespace containing traits for working on type packs. More...

Typedefs
Type pack traits (return a single type)
template<ptrdiff_t idx, typename... pack_t>
using	at = typename decltype(detail::at< idx, pack_t... >())::type
	Return the type at given index from the type pack.
template<typename... pack_t>
using	front = typename decltype(detail::front< pack_t... >())::type
	Return the first type from the type pack.
template<typename... pack_t>
using	back = typename decltype((std::type_identity< pack_t >{},...))::type
	Return the last type from the type pack.
Type pack traits (return a type list)
template<typename... pack_t>
using	drop_front = typename decltype(detail::drop_front< pack_t... >())::type
	Return a seqan3::type_list of all the types in the type pack, except the first.
template<template< typename > typename trait_t, typename... pack_t>
using	transform = seqan3::type_list< trait_t< pack_t >... >
	Apply a transformation trait to every type in the pack and return a seqan3::type_list of the results.
template<ptrdiff_t i, typename... pack_t>
using	take = typename decltype(detail::split_after< i, pack_t... >(type_list<>{}))::first_type
	Return a seqan3::type_list of the first n types in the type pack.
template<ptrdiff_t i, typename... pack_t>
using	drop = typename decltype(detail::split_after< i, pack_t... >(type_list<>{}))::second_type
	Return a seqan3::type_list of the types in the type pack, except the first n.
template<ptrdiff_t i, typename... pack_t>
using	take_last = drop< size< pack_t... > - i, pack_t... >
	Return a seqan3::type_list of the last n types in the type pack.
template<ptrdiff_t i, typename... pack_t>
using	drop_last = take< size< pack_t... > - i, pack_t... >
	Return a seqan3::type_list of the types the type pack, except the last n.
template<ptrdiff_t i, typename... pack_t>
using	split_after = decltype(detail::split_after< i, pack_t... >(type_list<>{}))
	Split a type pack into two parts returned as a pair of seqan3::type_list.
template<typename replace_t , std::ptrdiff_t i, typename... pack_t>
using	replace_at = decltype(detail::replace_at< replace_t, i, pack_t... >(std::make_index_sequence< size< pack_t... > >{}))
	Replace the type at the given index with the given type.

Variables
Type pack traits (return a value)
template<typename... pack_t>
constexpr size_t	size = sizeof...(pack_t)
	The size of a type pack.
template<typename query_t , typename... pack_t>
constexpr ptrdiff_t	count = (std::is_same_v<query_t, pack_t> + ... + 0)
	Count the occurrences of a type in a pack.
template<typename query_t , typename... pack_t>
constexpr ptrdiff_t	find = seqan3::pack_traits::detail::find<query_t, pack_t...>()
	Get the index of the first occurrence of a type in a pack.
template<template< typename > typename pred_t, typename... pack_t>
constexpr ptrdiff_t	find_if = seqan3::pack_traits::detail::find_if<pred_t, pack_t...>()
	Get the index of the first type in a pack that satisfies the given predicate.
template<typename query_t , typename... pack_t>
constexpr bool	contains = (find<query_t, pack_t...> != -1)
	Whether a type occurs in a pack or not.

Detailed Description

Namespace containing traits for working on type packs.