tuple-helper.hpp File Reference

Metaprogramming with tuples-of-types and the std::tuple record. More...

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Description

Metaprogramming with tuples-of-types and the std::tuple record.

This header complements typelist.hpp and provides a bridge from type sequences to the tuple type provided by the standard library, including traits and helpers to build tuple types from metaprogramming and to pretty-print tuples.

Notably, a concept tuple_like is provided, which is satisfied for any type in compliance with the »tuple protocol«. Together with a [generic accessor][lib::meta::getElm], this allows to handle all tuple-like types uniformly.

Note

Due to an unfortunate limitation of the standard, we're forced to provide our own alternative implementation to replace std::apply, so that a function can be applied to any tuple-like

Furthermore, a generic iteration construct is provided, to instantiate a generic Lambda for each element of a given tuple, which allows to write generic code »for each tuple element«.

See also

control::CommandDef usage example

TupleHelper_test

typelist.hpp

function.hpp

generator.hpp

Definition in file tuple-helper.hpp.

#include "lib/meta/typelist.hpp"
#include "lib/meta/typelist-util.hpp"
#include "lib/meta/typeseq-util.hpp"
#include "lib/meta/variadic-helper.hpp"
#include "lib/meta/util.hpp"
#include <tuple>
#include <utility>
#include <functional>

Namespaces
namespace	util
namespace	lib
	Implementation namespace for support and library code.
namespace	lib::meta
namespace	lib::meta::anonymous_namespace{tuple-helper.hpp}

Concepts
concept	lib::meta::tuple_sized
concept	lib::meta::tuple_adl_accessible
concept	lib::meta::tuple_mem_accessible
concept	lib::meta::tuple_element_accessible
concept	lib::meta::tuple_accessible
concept	lib::meta::tuple_like
	Concept to mark any type compliant to the »tuple protocol«

Typedefs
template<typename TYPES >
using	Tuple = BuildTupleType< TYPES >::Type
	Build a std::tuple from types given as type sequence.
template<class SRC , class TAR , size_t i>
using	ExtractArg = ElementExtractor< SRC, TAR >::template Access< i >

Classes
struct	is_Tuple< T >
	trait to detect tuple types More...
struct	is_Tuple< std::tuple< TYPES... > >
struct	is_Tuple< const std::tuple< TYPES... > >
struct	_InvokeMetafunTup< META, FUN, TUP >
struct	_InvokeMetafunTup< META, FUN, TUP & >
struct	ElmTypes< TUP >
	Specialisation of variadic access for any tuple-like. More...
struct	ElmTypes< TUP >::Extract< std::index_sequence< idx... > >
struct	BuildTupleType< SEQ >
struct	BuildTupleType< Types< TYPES... > >
struct	BuildTupleType< Node< H, TAIL > >
struct	BuildTupleType< Nil >
struct	RebindTupleTypes< TYPES >
	match and rebind the type sequence from a tuple More...
struct	RebindTupleTypes< std::tuple< TYPES... > >
struct	TupleConstructor< TYPES, _ElmMapper_ >
	Extensible Adapter to construct a distinct tuple from some arbitrary source type. More...
class	BuildTupleAccessor< _X_, TYPES, TUP, i >
	Decorating a tuple type with auxiliary data access operations. More...
class	BuildTupleAccessor< _X_, Types<>, TUP, i >
struct	TupleElementDisplayer< TY, BASE, TUP, idx >
	Helper to dump tuple contents. More...
struct	TupleElementDisplayer< Nil, TUP, TUP, n >
struct	StringConv< std::tuple< TYPES... > >

Functions
template<typename TY >
std::string	toString (TY const &val) noexcept
	get some string representation of any object, reliably.
template<std::size_t idx, class TUP > requires (tuple_like<std::remove_reference_t<TUP>>)
decltype(auto)	getElm (TUP &&tup)
	Helper for abstracted / unified access to member elements of any tuple-like
template<typename FUN , typename TUP , size_t... Idx>
constexpr decltype(auto)	__unpack_and_apply (FUN &&f, TUP &&tup, std::index_sequence< Idx... >)
template<class FUN , class TUP > requires (tuple_like<remove_reference_t<TUP>>)
constexpr decltype(auto)	apply (FUN &&f, TUP &&tup) noexcept(can_nothrow_invoke_tup< FUN, TUP >)
	Replacement for std::apply — yet applicable to tuple-like custom types.
template<class TUP , class FUN > requires (tuple_like<remove_reference_t<TUP>>)
constexpr void	forEach (TUP &&tuple, FUN fun)
	Tuple iteration: perform some arbitrary operation on each element of a tuple.
template<class TUP , class FUN > requires (tuple_like<remove_reference_t<TUP>>)
constexpr auto	mapEach (TUP &&tuple, FUN fun)
	Apply some arbitrary function onto all elements of a tuple.
template<typename TYPES , class SRC >
Tuple< TYPES >	buildTuple (SRC &&values)
	convenience shortcut to build a tuple from some suitable source data.
template<typename... TYPES>
std::string	dump (std::tuple< TYPES... > const &tuple)
	convenience function to dump a given tuple's contents.

Variables
template<class FUN , class TUP >
constexpr bool	can_nothrow_invoke_tup = _InvokeMetafunTup<std::is_nothrow_invocable,FUN,TUP>::Type::value

---

Class Documentation

lib::meta::anonymous_namespace{tuple-helper.hpp}::_InvokeMetafunTup

struct lib::meta::anonymous_namespace{tuple-helper.hpp}::_InvokeMetafunTup

Class Members
typedef decay_t< TUP >	Tupl
typedef Seq	Elms
typedef Seq	Args
typedef Type	Type

Collaboration diagram for _InvokeMetafunTup< META, FUN, TUP >:

lib::meta::anonymous_namespace{tuple-helper.hpp}::_InvokeMetafunTup< META, FUN, TUP & >

struct lib::meta::anonymous_namespace{tuple-helper.hpp}::_InvokeMetafunTup< META, FUN, TUP & >

Class Members
typedef decay_t< TUP >	Tupl
typedef typename template Apply< add_lvalue_reference_t >	Elms
typedef Seq	Args
typedef Type	Type

Collaboration diagram for _InvokeMetafunTup< META, FUN, TUP & >:

lib::meta::ElmTypes< TUP >::Extract< std::index_sequence< idx... > >

struct lib::meta::ElmTypes< TUP >::Extract< std::index_sequence< idx... > >

Class Members
typedef Types< tuple_element_t< idx, TUP > ... >	ElmTypes

Collaboration diagram for ElmTypes< TUP >::Extract< std::index_sequence< idx... > >:

lib::meta::anonymous_namespace{tuple-helper.hpp}::BuildTupleType< Types< TYPES... > >

struct lib::meta::anonymous_namespace{tuple-helper.hpp}::BuildTupleType< Types< TYPES... > >

Class Members
typedef tuple< TYPES... >	Type

Collaboration diagram for BuildTupleType< Types< TYPES... > >:

lib::meta::anonymous_namespace{tuple-helper.hpp}::BuildTupleType< Node< H, TAIL > >

struct lib::meta::anonymous_namespace{tuple-helper.hpp}::BuildTupleType< Node< H, TAIL > >

Class Members
typedef Types< Node< H, TAIL > >::Seq	Seq
typedef Type	Type

Collaboration diagram for BuildTupleType< Node< H, TAIL > >:

lib::meta::anonymous_namespace{tuple-helper.hpp}::BuildTupleType< Nil >

struct lib::meta::anonymous_namespace{tuple-helper.hpp}::BuildTupleType< Nil >

Class Members
typedef tuple<>	Type

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lib::meta::RebindTupleTypes

struct lib::meta::RebindTupleTypes

Class Members
typedef Seq	Seq
typedef List	List

Collaboration diagram for RebindTupleTypes< TYPES >:

lib::meta::RebindTupleTypes< std::tuple< TYPES... > >

struct lib::meta::RebindTupleTypes< std::tuple< TYPES... > >

Class Members
typedef Seq	Seq
typedef List	List

Collaboration diagram for RebindTupleTypes< std::tuple< TYPES... > >:

lib::meta::BuildTupleAccessor< _X_, Types<>, TUP, i >

class lib::meta::BuildTupleAccessor< _X_, Types<>, TUP, i >

Class Members
typedef _X_< Nil, TUP, TUP, i >	Product

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