variants::TaggedVariant< Tags > Class Template Reference

A class similar to std::variant, but indexed by tag structs. More...

#include <TaggedVariant.hpp>

Public Member Functions
	TaggedVariant ()=default
	A default constructed instance has the first tag active.
	TaggedVariant (const TaggedVariant &)=default
	TaggedVariant (TaggedVariant &&)=default
TaggedVariant &	operator= (const TaggedVariant &)=default
TaggedVariant &	operator= (TaggedVariant &&)=default
template<typename Tag, typename... Args, Requires<(... or std::is_same_v< Tag, Tags >) and std::is_constructible_v< typename Tag::type, Args... > > = nullptr>
constexpr	TaggedVariant (std::in_place_type_t< Tag >, Args &&... args)
	Construct with Tag active, using args to construct the contained object.
template<typename... Args, Requires< sizeof...(Tags)==1 and std::is_constructible_v< typename tmpl::front< TaggedVariant >::type, Args... > > = nullptr>
constexpr	TaggedVariant (Args &&... args)
	Construct the contained object from args. Only available if the TaggedVariant only has one tag.
constexpr size_t	index () const
	The index into the Tags... of the active object.
constexpr bool	valueless_by_exception () const
	See std::variant::valueless_by_exception.
template<typename Tag, typename... Args, Requires<(... or std::is_same_v< Tag, Tags >) and std::is_constructible_v< typename Tag::type, Args... > > = nullptr>
constexpr Tag::type &	emplace (Args &&... args)
	Destroys the contained object and actives Tag, constructing a new value from args.
constexpr void	swap (TaggedVariant &other) noexcept(noexcept((... and(std::is_nothrow_move_constructible_v< typename Tags::type > and std::is_nothrow_swappable_v< typename Tags::type >))))
void	pup (PUP::er &p)
template<typename... OtherTags, Requires< tmpl::size< tmpl::list_difference< TaggedVariant< OtherTags... >, TaggedVariant > >::value==0 > = nullptr>
constexpr	TaggedVariant (TaggedVariant< OtherTags... > &&other)
	A TaggedVariant can be implicitly move-converted to another variant with a superset of the tags.
template<typename... OtherTags, Requires< tmpl::size< tmpl::list_difference< TaggedVariant< OtherTags... >, TaggedVariant > >::value==0 > = nullptr>
constexpr TaggedVariant &	operator= (TaggedVariant< OtherTags... > &&other)
	A TaggedVariant can be implicitly move-converted to another variant with a superset of the tags.

Friends
template<typename Tag, typename... Tags2>
constexpr Tag::type &	get (TaggedVariant< Tags2... > &variant)
template<typename Tag, typename... Tags2>
constexpr const Tag::type &	get (const TaggedVariant< Tags2... > &variant)
template<typename Tag, typename... Tags2>
constexpr Tag::type &&	get (TaggedVariant< Tags2... > &&variant)
template<typename Tag, typename... Tags2>
constexpr const Tag::type &&	get (const TaggedVariant< Tags2... > &&variant)
constexpr bool	operator== (const TaggedVariant< Tags... > &a, const TaggedVariant< Tags... > &b)
constexpr bool	operator (const TaggedVariant< Tags... > &a, const TaggedVariant< Tags... > &b)
using	options = tmpl::list<Options::Alternatives<tmpl::list<Tags>...>>
	A TaggedVariant over option tags can be parsed as any of them.
static constexpr Options::String	help = "One of multiple options"
	A TaggedVariant over option tags can be parsed as any of them.
template<typename Tag>
	TaggedVariant (tmpl::list< Tag >, typename Tag::type value)
	A TaggedVariant over option tags can be parsed as any of them.

Detailed Description

template<typename... Tags>
class variants::TaggedVariant< Tags >

A class similar to std::variant, but indexed by tag structs.

See also

variants::get, variants::get_if, variants::holds_alternative, variants::visit

Constructor & Destructor Documentation

TaggedVariant() [1/3]

template<typename... Tags>

template<typename Tag, typename... Args, Requires<(... or std::is_same_v< Tag, Tags >) and std::is_constructible_v< typename Tag::type, Args... > > = nullptr>

variants::TaggedVariant< Tags >::TaggedVariant ( std::in_place_type_t< Tag > , Args &&... args )

inlineexplicitconstexpr

Construct with Tag active, using args to construct the contained object.

constexpr variants::TaggedVariant<Tags::Int, Tags::Templated<double>>
    int_variant(std::in_place_type<Tags::Int>, 1);

TaggedVariant() [2/3]

template<typename... Tags>

template<typename... Args, Requires< sizeof...(Tags)==1 and std::is_constructible_v< typename tmpl::front< TaggedVariant >::type, Args... > > = nullptr>

variants::TaggedVariant< Tags >::TaggedVariant ( Args &&... args )

inlineexplicitconstexpr

Construct the contained object from args. Only available if the TaggedVariant only has one tag.

constexpr variants::TaggedVariant<Tags::Int> simple_variant2(4);

TaggedVariant() [3/3]

template<typename... Tags>

template<typename... OtherTags, Requires< tmpl::size< tmpl::list_difference< TaggedVariant< OtherTags... >, TaggedVariant > >::value==0 > = nullptr>

variants::TaggedVariant< Tags >::TaggedVariant ( TaggedVariant< OtherTags... > && other )

inlineconstexpr

A TaggedVariant can be implicitly move-converted to another variant with a superset of the tags.

  variants::TaggedVariant<Tags::Int, Tags::Templated<double>> input(
      std::in_place_type<Tags::Int>, 4);
  variants::TaggedVariant<Tags::Templated<double>, Tags::Templated<int>,
                          Tags::Int>
      complex_converted(std::move(input));
  return get<Tags::Int>(complex_converted) == 4;

Member Function Documentation

emplace()

template<typename... Tags>

template<typename Tag, typename... Args, Requires<(... or std::is_same_v< Tag, Tags >) and std::is_constructible_v< typename Tag::type, Args... > > = nullptr>

Tag::type & variants::TaggedVariant< Tags >::emplace ( Args &&... args )

inlineconstexpr

Destroys the contained object and actives Tag, constructing a new value from args.

  variants::TaggedVariant<Tags::Int, Tags::Templated<double>> variant{};
  decltype(auto) emplace_result =
      variant.emplace<Tags::Templated<double>>(1.23);

operator=()

template<typename... Tags>

template<typename... OtherTags, Requires< tmpl::size< tmpl::list_difference< TaggedVariant< OtherTags... >, TaggedVariant > >::value==0 > = nullptr>

TaggedVariant & variants::TaggedVariant< Tags >::operator= ( TaggedVariant< OtherTags... > && other )

inlineconstexpr

A TaggedVariant can be implicitly move-converted to another variant with a superset of the tags.

  variants::TaggedVariant<Tags::Int, Tags::Templated<double>> input(
      std::in_place_type<Tags::Int>, 4);
  variants::TaggedVariant<Tags::Templated<double>, Tags::Templated<int>,
                          Tags::Int>
      complex_converted(std::move(input));
  return get<Tags::Int>(complex_converted) == 4;

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The documentation for this class was generated from the following file:

• src/DataStructures/TaggedVariant.hpp