sparrow::nullable_variant< T > Class Template Reference

Variant of nullable types with has_value() convenience method. More...

#include <nullable.hpp>

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Public Types
using	base_type = std::variant<T...>

Public Member Functions
template<class U, mpl::boolean_like B> requires ((std::same_as<nullable<U, B>, T> || ...))
constexpr	nullable_variant (const nullable< U, B > &value)
template<class... U> requires impl::materializable_into<nullable_variant<U...>, nullable_variant<T...>>
constexpr	nullable_variant (const nullable_variant< U... > &rhs)
	Converting constructor from another nullable variant.
template<class... U> requires impl::materializable_into<nullable_variant<U...>, nullable_variant<T...>>
constexpr nullable_variant &	operator= (const nullable_variant< U... > &rhs)
	Converting assignment operator from another nullable variant.
constexpr	nullable_variant (const nullable_variant &)=default
constexpr	nullable_variant (nullable_variant &&) noexcept=default
constexpr nullable_variant &	operator= (const nullable_variant &)
	Copy assignment operator.
constexpr nullable_variant &	operator= (nullable_variant &&) noexcept
	Move assignment operator.
constexpr	operator bool () const
	Conversion to bool indicating non-null state.
constexpr bool	has_value () const
	Checks whether the active alternative contains a valid value.

Detailed Description

template<class... T>
requires (sizeof...(T) > 0 && (is_nullable_v<T> && ...))
class sparrow::nullable_variant< T >

Variant of nullable types with has_value() convenience method.

This class extends std::variant to work specifically with nullable types, providing a uniform has_value() interface across all alternative types.

Template Parameters

T	Pack of nullable types that can be stored in the variant

Precondition

All types in T must be nullable types

sizeof...(T) must be > 0

Postcondition

Provides has_value() that works regardless of active alternative

Maintains all std::variant functionality

Examples

/home/runner/work/sparrow/sparrow/include/sparrow/utils/nullable.hpp.

Definition at line 1241 of file nullable.hpp.

Member Typedef Documentation

base_type

template<class... T>

using sparrow::nullable_variant< T >::base_type = std::variant<T...>

Examples

/home/runner/work/sparrow/sparrow/include/sparrow/utils/nullable.hpp.

Definition at line 1245 of file nullable.hpp.

Constructor & Destructor Documentation

nullable_variant() [1/4]

template<class... T>

template<class U, mpl::boolean_like B>
requires ((std::same_as<nullable<U, B>, T> || ...))

sparrow::nullable_variant< T >::nullable_variant ( const nullable< U, B > & value )

inlineconstexpr

Examples

/home/runner/work/sparrow/sparrow/include/sparrow/utils/nullable.hpp.

Definition at line 1250 of file nullable.hpp.

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nullable_variant() [2/4]

template<class... T>

template<class... U>
requires impl::materializable_into<nullable_variant<U...>, nullable_variant<T...>>

sparrow::nullable_variant< T >::nullable_variant ( const nullable_variant< U... > & rhs )

inlineconstexpr

Converting constructor from another nullable variant.

Converts each alternative to its owning counterpart, so a variant of references or views (e.g. array_traits::const_reference) converts to a variant of owned values (e.g. array_traits::value_type). Only available when every alternative of the source has exactly one owning counterpart among T (see impl::materialized).

Template Parameters

U	Alternative types of the source variant

Parameters

rhs	Variant to convert

Postcondition

The active alternative is the owning counterpart of the active alternative of rhs

Definition at line 1270 of file nullable.hpp.

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nullable_variant() [3/4]

template<class... T>

sparrow::nullable_variant< T >::nullable_variant ( const nullable_variant< T > & )

constexprdefault

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nullable_variant() [4/4]

template<class... T>

sparrow::nullable_variant< T >::nullable_variant ( nullable_variant< T > && )

constexprdefaultnoexcept

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Member Function Documentation

has_value()

template<class... T>
requires (sizeof...(T) > 0 && (is_nullable_v<T> && ...))

bool sparrow::nullable_variant< T >::has_value ( ) const

constexpr

Checks whether the active alternative contains a valid value.

Returns

true if active alternative is non-null, false otherwise

Postcondition

Calls has_value() on the active nullable alternative

Examples

/home/runner/work/sparrow/sparrow/include/sparrow/utils/nullable.hpp.

Definition at line 1620 of file nullable.hpp.

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operator bool()

template<class... T>
requires (sizeof...(T) > 0 && (is_nullable_v<T> && ...))

sparrow::nullable_variant< T >::operator bool ( ) const

explicitconstexpr

Conversion to bool indicating non-null state.

Returns

true if active alternative has a valid value

Postcondition

Return value equals has_value()

Definition at line 1613 of file nullable.hpp.

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operator=() [1/3]

template<class... T>
requires (sizeof...(T) > 0 && (is_nullable_v<T> && ...))

nullable_variant< T... > & sparrow::nullable_variant< T >::operator= ( const nullable_variant< T > & rhs )

constexpr

Copy assignment operator.

Parameters

rhs	Source variant to copy from

Returns

Reference to this variant

Postcondition

This variant contains a copy of rhs

Active alternative matches rhs

Definition at line 1597 of file nullable.hpp.

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operator=() [2/3]

template<class... T>

template<class... U>
requires impl::materializable_into<nullable_variant<U...>, nullable_variant<T...>>

nullable_variant & sparrow::nullable_variant< T >::operator= ( const nullable_variant< U... > & rhs )

inlineconstexpr

Converting assignment operator from another nullable variant.

See the converting constructor for the conditions under which the conversion is available.

Template Parameters

U	Alternative types of the source variant

Parameters

rhs	Variant to convert

Returns

Reference to this variant

Postcondition

The active alternative is the owning counterpart of the active alternative of rhs

Examples

/home/runner/work/sparrow/sparrow/include/sparrow/utils/nullable.hpp.

Definition at line 1289 of file nullable.hpp.

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operator=() [3/3]

template<class... T>
requires (sizeof...(T) > 0 && (is_nullable_v<T> && ...))

nullable_variant< T... > & sparrow::nullable_variant< T >::operator= ( nullable_variant< T > && rhs )

constexprnoexcept

Move assignment operator.

Parameters

rhs	Source variant to move from

Returns

Reference to this variant

Postcondition

This variant contains moved content from rhs

rhs is left in valid but unspecified state

Definition at line 1605 of file nullable.hpp.

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

• sparrow/utils/nullable.hpp