fcppt::variant::object< Types > Class Template Reference

Detailed Description

template<typename... Types>
class fcppt::variant::object< Types >

A class that can hold any object from a fixed set of types.

Template Parameters

Types

The list of element types. It may not contain dupiicates.

See fcppt.variant for more information.

Public Types
using	this_type = fcppt::variant::object<Types...>
using	types = fcppt::mpl::list::object<Types...>
	The mpl::list of the possible types.
using	std_type = fcppt::mpl::list::as<std::variant,types>

Public Member Functions
template<typename U > requires ( fcppt::mpl::list::contains_v<fcppt::mpl::list::object<Types...>, std::remove_cvref_t<U>>)
	object (U &&)
	Constructs the variant from a value.
template<typename U >
U const &	get_unsafe () const
	Returns a const reference to the held type without any checks.
template<typename U >
U &	get_unsafe ()
	Returns a reference to the held type without any checks.
fcppt::variant::size_type	type_index () const
	Returns the index of the held type.
bool	is_invalid () const
	Returns if the variant is invalid.
std_type &	impl ()
std_type const &	impl () const

Member Typedef Documentation

std_type

template<typename... Types>

using fcppt::variant::object< Types >::std_type = fcppt::mpl::list::as<std::variant,types>

this_type

template<typename... Types>

using fcppt::variant::object< Types >::this_type = fcppt::variant::object<Types...>

types

template<typename... Types>

using fcppt::variant::object< Types >::types = fcppt::mpl::list::object<Types...>

The mpl::list of the possible types.

Constructor & Destructor Documentation

object()

template<typename... Types>

template<typename U >
requires ( fcppt::mpl::list::contains_v<fcppt::mpl::list::object<Types...>, std::remove_cvref_t<U>>)

fcppt::variant::object< Types >::object ( U && )

explicit

Constructs the variant from a value.

Constructs the variant from value.

Template Parameters

U	Must be a type among types

Member Function Documentation

get_unsafe() [1/2]

template<typename... Types>

template<typename U >

U & fcppt::variant::object< Types >::get_unsafe ( )

nodiscard

Returns a reference to the held type without any checks.

Template Parameters

U	Must be a type among types

Warning

The behaviour is undefined if the variant does not contain U.

get_unsafe() [2/2]

template<typename... Types>

template<typename U >

U const & fcppt::variant::object< Types >::get_unsafe ( ) const

nodiscard

Returns a const reference to the held type without any checks.

Template Parameters

U	Must be a type among types

Warning

The behaviour is undefined if the variant does not contain U.

impl() [1/2]

template<typename... Types>

std_type & fcppt::variant::object< Types >::impl ( )

nodiscard

impl() [2/2]

template<typename... Types>

std_type const & fcppt::variant::object< Types >::impl ( ) const

nodiscard

is_invalid()

template<typename... Types>

bool fcppt::variant::object< Types >::is_invalid ( ) const

nodiscard

Returns if the variant is invalid.

This can only happen if an assignment of a different type throws an exception. There is no way to recover from that, except for falling back to heap allocation. An invalid variant should only be destroyed or assigned to.

type_index()

template<typename... Types>

fcppt::variant::size_type fcppt::variant::object< Types >::type_index ( ) const

nodiscard

Returns the index of the held type.

Returns

A runtime index into types of the held type.