TupleLookupByTag.h File Reference

Utilities to address elements of a tuple-like class by tag. More...

#include "larcorealg/CoreUtils/MetaUtils.h"
#include <cstddef>
#include <tuple>
#include <type_traits>

Go to the source code of this file.

Classes
struct	util::details::count_type_in_list_impl< Target, T >
struct	util::details::type_is_in_impl< Target, T >
struct	util::details::has_duplicate_types_unwrapper< Tuple >
struct	util::details::TagExtractorImpl< Tagged, typename >
struct	util::count_type_in_tuple< Target, Tuple >
	Holds whether the Target type is element of the specified std::tuple. More...
struct	util::extract_to_tuple_type< SrcTuple, Extractor, TargetClass >
	Returns type TargetClass<U...> from a SrcTuple<T...>. More...
struct	util::index_of_extracted_type< Extractor, Target, Tuple >
	Returns the index of the element in Tuple with the specified type. More...
struct	util::has_extracted_type< Extractor, Target, Tuple >
	Trait holding whether an element in Tuple type contains Target. More...
struct	util::has_duplicate_extracted_types< Extractor, Tuple >
	Traits holding whether elements of Tuple have duplicate types. More...
struct	util::count_extracted_types< Extractor, Target, Tuple >
	Counts the elements of a tuple-like type containing a Target type. More...
struct	util::TaggedType< T, Tag >
	A type with a specified tag. More...
struct	util::add_tag< T, Tag >
struct	util::remove_tag< Tagged >
	Trait holding the type contained in a TaggedType (or the type itself). More...
struct	util::remove_tag< TaggedType< T, Tag > >
struct	util::TagN<... >
	Tag class parametrized by a sequence of numbers. More...
struct	util::TagExtractor< Tagged >
	Extracts the tag from a type. More...
struct	util::details::count_type_in_list_impl< Target, T >
struct	util::details::count_type_in_list_impl< Target, First, Others... >
struct	util::details::count_type_in_list_impl< Target, Target, Others... >
struct	util::details::type_is_in_impl< Target, T >
struct	util::details::type_is_in_impl< Target, First, Others... >
struct	util::details::type_is_in_impl< Target, Target, Others... >
struct	util::details::extract_to_tuple_type_impl< TargetClass, Extractor, Tuple, I, N, T >
	Implementation for extract_to_tuple_type. More...
struct	util::details::extract_to_tuple_type_impl< TargetClass, Extractor, Tuple, N, N, T... >
	End-of-recursion specialization: packs all types already extracted into the target type. More...
struct	util::details::extract_to_tuple_type_impl_simple< SrcTuple, Extractor, TargetClass, I >
struct	util::details::index_of_extracted_type_impl< Extractor, Target, I, Elem, Tuple >
struct	util::details::index_of_extracted_type_checked< Extractor, Target, N, I, Tuple >
struct	util::details::index_of_extracted_type_checked< Extractor, Target, N, N, Tuple >
struct	util::details::index_of_extracted_type_impl< Extractor, Target, I, Elem, Tuple >
struct	util::details::index_of_extracted_type_impl< Extractor, Target, I, Target, Tuple >
struct	util::details::index_of_extracted_type_checked_after< Extractor, Target, N, After, Tuple >
struct	util::details::index_of_extracted_type_checked_after< Extractor, Target, N, N, Tuple >
struct	util::details::index_of_type_base< Extractor, Target, Tuple >
struct	util::details::index_of_type_helper< Extractor, Target, Tuple >
struct	util::details::has_duplicate_types_impl< Tuple, T >
struct	util::details::has_duplicate_types_impl< Tuple, First, Others... >
struct	util::details::has_duplicate_types_unwrapper< std::tuple< T... > >
struct	util::details::count_tags_in_list< Extractor, Target, Tags >
struct	util::details::count_tags_in_tuple< Extractor, Target, TagTuple >
struct	util::details::count_tags_in_tuple< Extractor, Target, std::tuple< Tags... > >
struct	util::details::TagExtractorImpl< Tagged, typename >
struct	util::details::TagExtractorImpl< Tagged, std::enable_if_t< always_true_type< typename std::remove_reference_t< Tagged >::tag >::value > >
struct	util::count_type_in_tuple< Target, Tuple >
	Holds whether the Target type is element of the specified std::tuple. More...
struct	util::count_type_in_tuple< Target, std::tuple< T... > >
struct	util::extract_to_tuple_type< SrcTuple, Extractor, TargetClass >
	Returns type TargetClass<U...> from a SrcTuple<T...>. More...
struct	util::index_of_extracted_type< Extractor, Target, Tuple >
	Returns the index of the element in Tuple with the specified type. More...
struct	util::has_extracted_type< Extractor, Target, Tuple >
	Trait holding whether an element in Tuple type contains Target. More...
struct	util::count_extracted_types< Extractor, Target, Tuple >
	Counts the elements of a tuple-like type containing a Target type. More...

Namespaces
	util
	Namespace for general, non-LArSoft-specific utilities.
	util::details

Typedefs
template<typename SrcTuple , template< typename T, typename... > class Extractor, template< typename... > class TargetClass = std::tuple>
using	util::extract_to_tuple_type_t = typename extract_to_tuple_type< SrcTuple, Extractor, TargetClass >::type
	Direct access to the type in extract_to_tuple_type. More...
template<typename Tuple , template< typename... > class TargetClass = std::tuple>
using	util::to_tuple = extract_to_tuple_type< Tuple, self_type, TargetClass >
template<typename Tuple , template< typename... > class TargetClass = std::tuple>
using	util::to_tuple_t = typename to_tuple< Tuple, TargetClass >::type
	Direct access to the type in to_tuple. More...
template<typename Target , typename Tuple >
using	util::index_of_type = index_of_extracted_type< self_type, Target, Tuple >
template<template< typename T, typename... > class Extractor, typename Target , typename Tuple >
using	util::type_with_extracted_type = std::tuple_element< index_of_extracted_type_v< Extractor, Target, Tuple >, Tuple >
	Returns the element type in Tuple with the specified type. More...
template<template< typename T, typename... > class Extractor, typename Target , typename Tuple >
using	util::type_with_extracted_type_t = typename type_with_extracted_type< Extractor, Target, Tuple >::type
	Direct access to the value in type_with_extracted_type. More...
template<typename Target , typename Tuple >
using	util::has_type = has_extracted_type< self_type, Target, Tuple >
template<typename Tuple >
using	util::has_duplicate_types = has_duplicate_extracted_types< self_type, Tuple >
template<typename Target , typename Tuple >
using	util::count_types = count_extracted_types< self_type, Target, Tuple >
template<typename T , typename Tag >
using	util::add_tag_t = typename add_tag< T, Tag >::type
template<typename Tagged >
using	util::remove_tag_t = typename remove_tag< Tagged >::type
	Direct access to the type contained in remove_tag. More...
template<typename Tagged >
using	util::tag_of = TagExtractor< Tagged >
	Trait holding the tag of Tagged as type. More...
template<typename Tagged >
using	util::tag_of_t = typename tag_of< Tagged >::type
	Direct access to the type in tag_of. More...
template<typename SrcTuple >
using	util::extract_tags = extract_to_tuple_type< SrcTuple, TagExtractor >
	Returns a tuple with all the tags from SrcTuple. More...
template<typename SrcTuple >
using	util::extract_tags_t = typename extract_tags< SrcTuple >::type
	Direct access to the type in extract_tags. More...
template<typename Tag , typename Tuple >
using	util::index_of_tag = index_of_extracted_type< TagExtractor, Tag, Tuple >
	Trait holding the index of the element of Tuple with tag Tag. More...
template<typename Tag , typename Tuple >
using	util::type_with_tag = type_with_extracted_type< TagExtractor, Tag, Tuple >
	Trait holding the type of the element of Tuple with tag Tag. More...
template<typename Tag , typename Tuple >
using	util::type_with_tag_t = typename type_with_tag< Tag, Tuple >::type
	Direct access to the value in type_with_tag. More...
template<typename Tag , typename Tuple >
using	util::has_tag = has_extracted_type< TagExtractor, Tag, Tuple >
	Trait informing if there are elements in Tuple with tag Tag. More...
template<typename Tag , typename Tuple >
using	util::count_tags = count_extracted_types< TagExtractor, Tag, Tuple >
	Trait counting the elements in Tuple with tag Tag. More...
template<typename Tuple >
using	util::has_duplicate_tags = has_duplicate_extracted_types< TagExtractor, Tuple >
	Trait reporting if multiple elements in Tuple have the same tag. More...

Functions
template<template< typename T, typename... > class Extractor, typename Target , typename Tuple >
auto	util::getByExtractedType (Tuple const &data) -> decltype(auto)
	Returns the value of the element containing the specified type. More...
template<typename Tag , typename T >
auto	util::makeTagged (T &obj) -> decltype(auto)
	"Converts" obj to an object with tag Tag. More...
template<typename Tag , typename T >
auto	util::makeTagged (T const &obj) -> decltype(auto)
	"Converts" obj to an object with tag Tag. More...
template<typename Tag , typename T >
auto	util::makeTagged (T const &&obj) -> decltype(auto)
	"Converts" obj to an object with tag Tag. More...
template<typename Tag , typename T >
auto	util::makeTagged (T &&obj) -> decltype(auto)
	"Converts" obj to an object with tag Tag. More...
template<typename Tagged >
auto	util::removeTag (Tagged &tagged) -> decltype(auto)
	"Converts" a tagged type back to its original type. More...
template<typename Tagged >
auto	util::removeTag (Tagged const &tagged) -> decltype(auto)
	"Converts" a tagged type back to its original type. More...
template<typename Tagged >
auto	util::removeTag (Tagged const &&tagged) -> decltype(auto)
	"Converts" a tagged type back to its original type. More...
template<typename Tagged >
auto	util::removeTag (Tagged &&tagged) -> decltype(auto)
	"Converts" a tagged type back to its original type. More...
template<typename Tag , typename Tuple >
auto	util::getByTag (Tuple const &data) -> decltype(auto)
	Returns the object with the specified tag. More...

Variables
template<template< typename T, typename... > class Extractor, typename Target , typename Tuple >
constexpr std::size_t	util::index_of_extracted_type_v
	Direct access to the value in index_of_extracted_type. More...
template<typename Target , typename Tuple >
constexpr std::size_t	util::index_of_type_v = index_of_type<Target, Tuple>()
	Direct access to the value in index_of_type. More...
template<template< typename T, typename... > class Extractor, typename Target , typename Tuple >
constexpr bool	util::has_extracted_type_v = has_extracted_type<Extractor, Target, Tuple>()
	Direct access to the value in has_extracted_type. More...
template<typename Target , typename Tuple >
constexpr bool	util::has_type_v = has_type<Target, Tuple>()
	Direct access to the value in has_type. More...
template<template< typename T, typename... > class Extractor, typename Tuple >
constexpr bool	util::has_duplicate_extracted_types_v
	Direct access to the value in has_duplicate_extracted_types. More...
template<typename Tuple >
constexpr bool	util::has_duplicate_types_v = has_duplicate_types<Tuple>()
	Direct access to the value in has_duplicate_types. More...
template<template< typename T, typename... > class Extractor, typename Target , typename Tuple >
constexpr unsigned int	util::count_extracted_types_v
	Direct access to the value in count_extracted_types. More...
template<typename Target , typename Tuple >
constexpr unsigned int	util::count_types_v = count_types<Target, Tuple>()
	Direct access to the value in count_extracted_types. More...
template<typename Tag , typename Tuple >
constexpr std::size_t	util::index_of_tag_v = index_of_tag<Tag, Tuple>()
	Direct access to the value in index_of_tag. More...
template<typename Tag , typename Tuple >
constexpr bool	util::has_tag_v = has_tag<Tag, Tuple>()
	Direct access to the value in has_tag. More...
template<typename Tag , typename Tuple >
constexpr unsigned int	util::count_tags_v = count_tags<Tag, Tuple>()
	Direct access to the value in count_tags. More...
template<typename Tuple >
constexpr bool	util::has_duplicate_tags_v = has_duplicate_tags<Tuple>()
	Direct access to the value in has_duplicate_tags. More...
template<typename Target , typename... T>
using	util::count_type_in_list = details::count_type_in_list_impl< Target, T... >
	Returns how many of the types in T exactly match Target. More...
template<std::size_t N, typename... T>
using	util::typelist_element_type = std::tuple_element< N, std::tuple< T... >>
	Returns the N type of the type list. More...
template<std::size_t N, typename... T>
using	util::typelist_element_t = typename typelist_element_type< N, T... >::type
	Direct access to the value in typelist_element_type. More...
template<typename Target , typename... T>
using	util::type_is_in = details::type_is_in_impl< Target, T... >
	Holds whether the Target type is among the ones in the T pack. More...
template<typename Target , typename... T>
constexpr unsigned int	util::count_type_in_list_v = count_type_in_list<Target, T...>()
	Direct access to the value in count_type_in_list. More...
template<typename Target , typename... T>
constexpr bool	util::type_is_in_v = type_is_in<Target, T...>()
	Direct access to the value in type_is_in. More...

Detailed Description

Utilities to address elements of a tuple-like class by tag.

Author

Gianluca Petrillo

Date

August 17, 2018

A "tagged" class is a class containing a type named "tag". The class is tagged by it. A container of objects, tuple-like, can be accessed by specifying the type of the tag. For example:

std::tuple<TaggedItem1, TaggedItem2, TaggedItem3> data;

auto tagBdata = util::getByTag<TagB>(data);

will assign tagBdata with one of the three components of the data objects, the one whose type has tag equal to TagB.

The type being processed must be "tuple-like" (in the example above, the type of data is in fact a tuple). This means that the type must respond to std::tuple_element and std::tuple_size.

Beside these utilities, equivalent utilities are exposed that allow a different definition of the tag (via a class "returning" the tag of its only template argument), and that operate on the types directly rather than on the tags (equivalent to define the tag as the object itself).

All the type trait utilities follow the standard C++ convention: the ones "returning" a type have that type in a type member, and the ones returning a value have that value in a value member, and their instances can be implicitly converted to that value. Aliases ending with _t and _v are also provided.

This is a header-only library providing mostly type trait information.

Definition in file TupleLookupByTag.h.