liber::optref< T > Struct Template Reference

A std::optional<std::reference_wrapper<T>> wrapper for lvalue references. More...

#include <optref.hpp>

Public Types
using	value_type = T
	Value type.
using	reference_type = std::add_lvalue_reference_t< T >
	Reference type.
using	const_reference_type = std::add_const_t< reference_type >
	Const reference type.
using	reference_wrapper_type = std::reference_wrapper< value_type >
	Reference wrapper type for std::optional.

Public Member Functions
constexpr	optref () noexcept
	Default constructor - std::optional contains no reference.
constexpr	optref (std::nullopt_t) noexcept
	Nullopt constructor - no reference.
constexpr	optref (const optref &other) noexcept
	Copy constructor.
template<typename U > requires std::convertible_to<U&, T&>
constexpr	optref (const optref< U > &other) noexcept
	Converting copy constructor for base/derived class references.
constexpr	optref (T &reference) noexcept
	Construct an optref from reference.
constexpr	optref (std::reference_wrapper< T > wrapper) noexcept
	Construct an optref from std::reference_wrapper.
constexpr	optref (T *pointer) noexcept
	Construct an optref from a pointer.
constexpr bool	has_reference () const noexcept
	Does it contain a reference?
constexpr	operator bool () const noexcept
	Does it contain a reference?
constexpr reference_type	reference ()
	Get the contained reference; throws if none.
constexpr const_reference_type	reference () const
	Get the contained const reference; throws if none.
void	swap (optref &other) noexcept
	Swap implementation.
void	reset () noexcept
	Reset (cannot assign after).

Detailed Description

template<typename T>
requires requires { !std::is_reference_v<T>; }
struct liber::optref< T >

A std::optional<std::reference_wrapper<T>> wrapper for lvalue references.

Satisfies CopyConstructible, CopyAssignable and TriviallyCopyable.

Template Parameters

T	the (optionally) referenced object

Constructor & Destructor Documentation

optref()

template<typename T >

template<typename U >
requires std::convertible_to<U&, T&>

constexpr liber::optref< T >::optref ( const optref< U > &  other )

inlineconstexprnoexcept

Converting copy constructor for base/derived class references.

Template Parameters

U	another class that is convertible to T

Parameters

other

Member Function Documentation

has_reference()

template<typename T >

constexpr bool liber::optref< T >::has_reference ( ) const

inlineconstexprnoexcept

Does it contain a reference?

Returns

true

false

operator bool()

template<typename T >

constexpr liber::optref< T >::operator bool ( ) const

inlineexplicitconstexprnoexcept

Does it contain a reference?

Returns

true

false

reference() [1/2]

template<typename T >

constexpr reference_type liber::optref< T >::reference ( )

inlineconstexpr

Get the contained reference; throws if none.

Exceptions

std::bad_optional_access

Returns

reference_type the reference

reference() [2/2]

template<typename T >

constexpr const_reference_type liber::optref< T >::reference ( ) const

inlineconstexpr

Get the contained const reference; throws if none.

Exceptions

std::bad_optional_access

Returns

const_reference_type the const reference

swap()

template<typename T >

void liber::optref< T >::swap ( optref< T > &  other )

inlinenoexcept

Swap implementation.

Parameters

other

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

• include/detail/optref.hpp