A value that may be replaced by an error code. More...

#include <eh/Failable.hpp>

Public Member Functions
template<typename RhsValue > requires std::equality_comparable_with<Value, detail::IfNotFailable<RhsValue>> && (!std::is_same_v<std::remove_cvref_t<RhsValue>, std::error_code>) && (!std::is_error_code_enum_v<RhsValue>)
auto	operator== (const RhsValue &value) -> bool
	Comparison operator for a valid value.

auto	operator== (const std::error_code &errorCode) -> bool
	Comparison operator for an error code.

template<typename Enum > requires std::is_error_code_enum_v<Enum>
auto	operator== (Enum errorEnum) noexcept -> Failable &
	Comparison operator for an error enum.

Constructing valid values
	Failable () noexcept(std::is_nothrow_constructible_v< Value >)
	Default Constructor. Constructs an object containing a default constructed value.

template<typename Initializer > requires std::is_constructible_v<Value, Initializer &&> && (!std::is_same_v<std::remove_cvref_t<Initializer>, std::in_place_t>) && (!std::is_same_v<std::remove_cvref_t<Initializer>, Failable<Value>>) && (!std::is_same_v<std::remove_cvref_t<Initializer>, std::error_code>) && (!std::is_error_code_enum_v<Initializer>)
	Failable (Initializer &&initializer) noexcept(std::is_nothrow_constructible_v< Value, Initializer && >)
	Constructor that constructs a valid value from an initializer.

template<typename Argument1 , typename Argument2 , typename... MoreArguments> requires std::is_constructible_v<Value, Argument1 &&, Argument2 &&, MoreArguments &&...> && (!std::is_same_v<std::remove_cvref_t<Argument1>, std::in_place_t>) && (!std::is_constructible_v<std::error_code, Argument1 &&, Argument2 &&, MoreArguments &&...>)
	Failable (Argument1 &&argument1, Argument2 &&argument2, MoreArguments &&... moreArguments) noexcept(std::is_nothrow_constructible_v< Value, Argument1 &&, Argument2 &&, MoreArguments &&... >)
	Constructor that constructs a valid value from two or more arguments.

template<typename... Arguments> requires std::is_constructible_v<Value, Arguments...>
	Failable (std::in_place_t, Arguments &&... arguments) noexcept(std::is_nothrow_constructible_v< Value, Arguments &&... >)
	In-place constructor.

Constructing error objects
	Failable (const std::error_code &errorCode) noexcept
	Constructor for an error code.

	Failable (int errorValue, const std::error_category &category) noexcept
	Constructor for an error value.

template<typename Enum > requires std::is_error_code_enum_v<Enum>
	Failable (Enum errorEnum) noexcept
	Constructor for an error enum.

Assigning valid values
template<typename NewValue > requires std::is_assignable_v<Value, NewValue &&> && std::is_constructible_v<Value, NewValue &&> && (!std::is_same_v<std::remove_cvref_t<NewValue>, Failable<Value>>) && (!std::is_same_v<std::remove_cvref_t<NewValue>, std::error_code>) && (!std::is_error_code_enum_v<NewValue>)
auto	operator= (NewValue &&newValue) noexcept(std::is_nothrow_assignable_v< Value, NewValue && > &&std::is_nothrow_constructible_v< Value, NewValue && >) -> Failable &
	Assignment operator for a valid value.

Assigning errors
auto	operator= (const std::error_code &errorCode) noexcept -> Failable &
	Assignment operator for an error code.

auto	assign (int errorValue, const std::error_category &category) noexcept -> Failable &
	Assigns an error value from within a certain error category.

template<typename Enum > requires std::is_error_code_enum_v<Enum>
auto	operator= (Enum errorEnum) noexcept -> Failable &
	Assignment operator for an error enum.

Copying, Moving, and Assigning other [Failable]s
	Failable (const Failable &)=default
	Copy constructor.

	Failable (Failable &&)=default
	Move constructor.

template<typename RelatedValue > requires std::is_constructible_v<Value, const RelatedValue &> && (!std::is_same_v<RelatedValue, Value>)
	Failable (const Failable< RelatedValue > &relatedValue) noexcept(std::is_nothrow_constructible_v< Value, const RelatedValue & >)
	Copy constructor for related Failable.

template<typename RelatedValue > requires std::is_constructible_v<Value, RelatedValue &&> && (!std::is_same_v<RelatedValue, Value>)
	Failable (Failable< RelatedValue > &&relatedValue) noexcept(std::is_nothrow_constructible_v< Value, RelatedValue && >)
	Move constructor for related Failable.

auto	operator= (const Failable &) -> Failable &=default
	Assignment operator.

auto	operator= (Failable &&) -> Failable &=default
	Move assignment operator.

template<typename RelatedValue > requires std::is_assignable_v<Value, const RelatedValue &> && std::is_constructible_v<Value, const RelatedValue &> && (!std::is_same_v<RelatedValue, Value>)
auto	operator= (const Failable< RelatedValue > &relatedValue) noexcept(std::is_nothrow_constructible_v< Value, const RelatedValue & >) -> Failable &
	Assignment operator for related value.

template<typename RelatedValue > requires std::is_assignable_v<Value, RelatedValue &&> && std::is_constructible_v<Value, RelatedValue &&> && (!std::is_same_v<RelatedValue, Value>)
auto	operator= (Failable< RelatedValue > &&relatedValue) noexcept(std::is_nothrow_assignable_v< Value, RelatedValue && > &&std::is_nothrow_constructible_v< Value, RelatedValue && >) -> Failable &
	Move assignment operator for related value.

Accessing the value
	operator bool () const noexcept
	Determines if the object contains a valid value.

auto	operator* () noexcept -> Value &
	Gets the value without checking.

auto	operator* () const noexcept -> const Value &
	Gets the value without checking.

auto	operator-> () noexcept -> std::add_pointer_t< Value >
	Accesses a member of the contained value without checking.

auto	operator-> () const noexcept -> std::add_pointer_t< const Value >
	Accesses a member of the contained value without checking.

auto	hasValue () const noexcept -> bool
	Determines if the object contains a valid value.

auto	value () noexcept -> std::add_pointer_t< Value >
	Gets the value, if there is one.

auto	value () const noexcept -> std::add_pointer_t< const Value >
	Gets the value, if there is one.

auto	valueOr (const Value &fallback) const &noexcept(std::is_nothrow_copy_constructible_v< Value >) -> Value
	Gets the value or a fallback value.

auto	valueOr (Value &&fallback) const &noexcept(std::is_nothrow_copy_constructible_v< Value > &&std::is_nothrow_move_constructible_v< Value >) -> Value
	Gets the value or a fallback value.

auto	valueOr (const Value &fallback) &&noexcept(std::is_nothrow_copy_constructible_v< Value > &&std::is_nothrow_move_constructible_v< Value >) -> Value
	Gets the value or a fallback value.

auto	valueOr (Value &&fallback) &&noexcept(std::is_nothrow_move_constructible_v< Value >) -> Value
	Gets the value or a fallback value.

auto	valueOr (std::reference_wrapper< const Value > fallback) const noexcept -> const Value &
	Gets a reference to the value or to a fallback value.

auto	valueOr (std::reference_wrapper< Value > fallback) noexcept -> Value &
	Gets a mutable reference to the value or to a fallback value.

template<std::invocable<> Fallback>
auto	valueOr (Fallback &&fallback) const &noexcept(std::is_nothrow_invocable_r_v< Value, Fallback && >) -> Value
	Gets the value or generates a fallback value.

template<std::invocable<> Fallback>
auto	valueOr (Fallback &&fallback) &&noexcept(std::is_nothrow_invocable_r_v< Value, Fallback && >) -> Value
	Gets the value or generates a fallback value.

template<std::invocable<> Fallback> requires std::is_reference_v<std::invoke_result_t<Fallback &&>> && std::convertible_to<std::invoke_result_t<Fallback &&>, const Value&>
auto	valueOr (Fallback &&fallback) const -> const Value &
	Gets the value or generates a fallback value.

template<std::invocable<> Fallback> requires std::is_reference_v<std::invoke_result_t<Fallback &&>> && std::convertible_to<std::invoke_result_t<Fallback &&>, Value&>
auto	valueOr (Fallback &&fallback) -> Value &
	Gets the value or generates a reference to a fallback value.

template<std::derived_from< std::system_error > Exception = std::system_error, typename... ExceptionArguments>
auto	valueOrThrow (ExceptionArguments &&... exceptionArguments) const -> const Value &
	Gets the value, or throws the error.

template<std::derived_from< std::system_error > Exception = std::system_error, typename... ExceptionArguments>
auto	valueOrThrow (ExceptionArguments &&... exceptionArguments) -> Value &
	Gets the value, or throws the error.

Accessing the error
auto	error () const noexcept -> std::error_code
	Gets the error, if there is one.

template<std::derived_from< std::system_error > Exception = std::system_error, typename... ExceptionArguments>
auto	throwError (ExceptionArguments &&... exceptionArguments) const -> void
	Throws the error if the object contains an error instead of a value.

Conversion to std::optional
	operator std::optional< Value > () const &
	Returns the value as an optional.

	operator std::optional< Value > () &&
	Returns the value as an optional.

Related Symbols
(Note that these are not member symbols.)
template<typename LhsValue , typename RhsValue >
auto	operator== (const Failable< LhsValue > &lhs, const Failable< RhsValue > &rhs) -> bool
	Comparison operator for two failables.

template<typename RelatedValue , typename Value >
auto	failableCast (const Failable< Value > &failable) noexcept(std::is_nothrow_constructible_v< RelatedValue, const Value & >) -> Failable< RelatedValue >
	Explicitly casts a failable to a related type.

template<typename RelatedValue , typename Value >
auto	failableCast (Failable< Value > &&failable) noexcept(std::is_nothrow_constructible_v< RelatedValue, Value && >) -> Failable< RelatedValue >
	Explicitly casts a failable to a related type.

Detailed Description

template<typename Value>
class xentara::utils::eh::Failable< Value >

A value that may be replaced by an error code.

Template Parameters

Value The type of value that the object should contain

Deprecated:: This class has been deprecated in favour of xentara::utils::eh::expected

Constructor & Destructor Documentation

◆ Failable() [1/11]

template<typename Value >

xentara::utils::eh::Failable< Value >::Failable ( )

noexcept

Default Constructor. Constructs an object containing a default constructed value.

◆ Failable() [2/11]

template<typename Value >

template<typename Initializer >
requires std::is_constructible_v<Value, Initializer &&> && (!std::is_same_v<std::remove_cvref_t<Initializer>, std::in_place_t>) && (!std::is_same_v<std::remove_cvref_t<Initializer>, Failable<Value>>) && (!std::is_same_v<std::remove_cvref_t<Initializer>, std::error_code>) && (!std::is_error_code_enum_v<Initializer>)

xentara::utils::eh::Failable< Value >::Failable ( Initializer && initializer )

noexcept

Constructor that constructs a valid value from an initializer.

Note: You cannot use this constructor to initialize the value with an object of type std::in_place_t, std::error_code, or with an error code enum for which std::is_error_code_enum_v is true. Use the in place constructor instead.

Parameters

initializer The object to initialize the value with.

◆ Failable() [3/11]

template<typename Value >

template<typename Argument1 , typename Argument2 , typename... MoreArguments>
requires std::is_constructible_v<Value, Argument1 &&, Argument2 &&, MoreArguments &&...> && (!std::is_same_v<std::remove_cvref_t<Argument1>, std::in_place_t>) && (!std::is_constructible_v<std::error_code, Argument1 &&, Argument2 &&, MoreArguments &&...>)

xentara::utils::eh::Failable< Value >::Failable	(	Argument1 &&	argument1,
		Argument2 &&	argument2,
		MoreArguments &&...	moreArguments
	)

noexcept

Constructor that constructs a valid value from two or more arguments.

Note: If the first argument is of type std::in_place_t, the in place constructor will be called instead. If you need to initialize an object with an argument list that start with std::in_place, you must specify std::in_place twice.

Similarly, if the first argument is convertible to an integer, and the second argument is a reference to an std::error_category, the error constructor will be called instead. In that case, you need prefix the parameters with std::in_place.

Parameters

argument1	The first argument to pass to the value's constructor.
argument2	The first argument to pass to the value's constructor.
moreArguments	The remaining arguments to pass to the value's constructor, if any.

◆ Failable() [4/11]

template<typename Value >

template<typename... Arguments>
requires std::is_constructible_v<Value, Arguments...>

xentara::utils::eh::Failable< Value >::Failable	(	std::in_place_t	,
		Arguments &&...	arguments
	)

noexcept

In-place constructor.

This constructor constructs a valid object from a list of arguments.

Parameters

arguments The arguments to pass to the value's constructor.

◆ Failable() [5/11]

template<typename Value >

xentara::utils::eh::Failable< Value >::Failable ( const std::error_code & errorCode )

noexcept

Constructor for an error code.

This constructor constructs an invalid object containing the specified error code.

Parameters

errorCode The desired error code.

◆ Failable() [6/11]

template<typename Value >

xentara::utils::eh::Failable< Value >::Failable	(	int	errorValue,
		const std::error_category &	category
	)

noexcept

Constructor for an error value.

This constructor constructs an invalid object containing the specified error value and category.

Parameters

errorValue	The desired error value.
category	The relevant error category.

◆ Failable() [7/11]

template<typename Value >

template<typename Enum >
requires std::is_error_code_enum_v<Enum>

xentara::utils::eh::Failable< Value >::Failable ( Enum errorEnum )

noexcept

Constructor for an error enum.

This constructor constructs an invalid object containing the error code corresponding to the specified error enum.

Parameters

errorEnum The desired error enum.

◆ Failable() [8/11]

template<typename Value >

xentara::utils::eh::Failable< Value >::Failable ( const Failable< Value > & )

default

Copy constructor.

◆ Failable() [9/11]

template<typename Value >

xentara::utils::eh::Failable< Value >::Failable ( Failable< Value > && )

default

Move constructor.

◆ Failable() [10/11]

template<typename Value >

template<typename RelatedValue >
requires std::is_constructible_v<Value, const RelatedValue &> && (!std::is_same_v<RelatedValue, Value>)

xentara::utils::eh::Failable< Value >::Failable ( const Failable< RelatedValue > & relatedValue ) const &

noexcept

Copy constructor for related Failable.

Copies the value or error from a Failable of a related type

◆ Failable() [11/11]

template<typename Value >

template<typename RelatedValue >
requires std::is_constructible_v<Value, RelatedValue &&> && (!std::is_same_v<RelatedValue, Value>)

xentara::utils::eh::Failable< Value >::Failable ( Failable< RelatedValue > && relatedValue ) const &&

noexcept

Move constructor for related Failable.

Moves the value or error from a Failable of a related type

Member Function Documentation

◆ assign()

template<typename Value >

auto xentara::utils::eh::Failable< Value >::assign	(	int	errorValue,
		const std::error_category &	category
	)		-> Failable &

noexcept

Assigns an error value from within a certain error category.

This constructor constructs an invalid object containing the specified error value and category.

Parameters

errorValue	The desired error value.
category	The relevant error category.

Returns: A reference to this object

◆ error()

template<typename Value >

auto xentara::utils::eh::Failable< Value >::error ( ) const -> std::error_code

noexcept

Gets the error, if there is one.

Returns: The error, or std::error_code() if the object contains a value instead of an error

◆ hasValue()

template<typename Value >

auto xentara::utils::eh::Failable< Value >::hasValue ( ) const -> bool

noexcept

Determines if the object contains a valid value.

Returns: Return true if the object contains a value, or false if it contains an error.

◆ operator bool()

template<typename Value >

xentara::utils::eh::Failable< Value >::operator bool ( ) const

explicitnoexcept

Determines if the object contains a valid value.

Returns: Return true if the object contains a value, or false if it contains an error.

◆ operator std::optional< Value >() [1/2]

template<typename Value >

xentara::utils::eh::Failable< Value >::operator std::optional< Value > ( ) &&

Returns the value as an optional.

Returns: The value, or std::nullopt if the object does not contain a valid value

◆ operator std::optional< Value >() [2/2]

template<typename Value >

xentara::utils::eh::Failable< Value >::operator std::optional< Value > ( ) const &

Returns the value as an optional.

Returns: The value, or std::nullopt if the object does not contain a valid value

◆ operator*() [1/2]

template<typename Value >

auto xentara::utils::eh::Failable< Value >::operator* ( ) const -> const Value &

noexcept

Gets the value without checking.

Attention: No check is performed to verify that object actually contains a valid value. This function must only be called after checking that the value is valid using hasValue() or operator bool().

Returns: The value. If the object does not contain a value, the return value is not usable.

◆ operator*() [2/2]

template<typename Value >

auto xentara::utils::eh::Failable< Value >::operator* ( ) -> Value &

noexcept

Gets the value without checking.

Attention: No check is performed to verify that object actually contains a valid value. This function must only be called after checking that the value is valid using hasValue() or operator bool().

Returns: The value. If the object does not contain a value, the return value is not usable.

◆ operator->() [1/2]

template<typename Value >

auto xentara::utils::eh::Failable< Value >::operator-> ( ) const -> std::add_pointer_t<const Value>

noexcept

Accesses a member of the contained value without checking.

Attention: No check is performed to verify that object actually contains a valid value. This function must only be called after checking that the value is valid using hasValue() or operator bool().

Returns: A pointer to the value. If the object does not contain a value, the return value is not usable.

◆ operator->() [2/2]

template<typename Value >

auto xentara::utils::eh::Failable< Value >::operator-> ( ) -> std::add_pointer_t<Value>

noexcept

Accesses a member of the contained value without checking.

Attention: No check is performed to verify that object actually contains a valid value. This function must only be called after checking that the value is valid using hasValue() or operator bool().

Returns: A pointer to the value. If the object does not contain a value, the return value is not usable.

◆ operator=() [1/7]

template<typename Value >

auto xentara::utils::eh::Failable< Value >::operator= ( const Failable< Value > & ) -> Failable &=default

default

Assignment operator.

◆ operator=() [2/7]

template<typename Value >

template<typename RelatedValue >
requires std::is_assignable_v<Value, const RelatedValue &> && std::is_constructible_v<Value, const RelatedValue &> && (!std::is_same_v<RelatedValue, Value>)

auto xentara::utils::eh::Failable< Value >::operator= ( const Failable< RelatedValue > & relatedValue ) const & -> Failable &

noexcept

Assignment operator for related value.

Copies the value or error from a related convertible value

Returns: A reference to this object

◆ operator=() [3/7]

template<typename Value >

auto xentara::utils::eh::Failable< Value >::operator= ( const std::error_code & errorCode ) -> Failable &

noexcept

Assignment operator for an error code.

Turns the object into an invalid object containing the specified error code.

Parameters

errorCode The desired error code.

Returns: A reference to this object

◆ operator=() [4/7]

template<typename Value >

template<typename Enum >
requires std::is_error_code_enum_v<Enum>

auto xentara::utils::eh::Failable< Value >::operator= ( Enum errorEnum ) -> Failable &

noexcept

Assignment operator for an error enum.

Turns the object into an invalid object containing the error code corresponding to the specified error enum.

Parameters

errorEnum The desired error enum.

Returns: A reference to this object

◆ operator=() [5/7]

template<typename Value >

auto xentara::utils::eh::Failable< Value >::operator= ( Failable< Value > && ) -> Failable &=default

default

Move assignment operator.

◆ operator=() [6/7]

template<typename Value >

template<typename RelatedValue >
requires std::is_assignable_v<Value, RelatedValue &&> && std::is_constructible_v<Value, RelatedValue &&> && (!std::is_same_v<RelatedValue, Value>)

auto xentara::utils::eh::Failable< Value >::operator= ( Failable< RelatedValue > && relatedValue ) const && -> Failable &

noexcept

Move assignment operator for related value.

Moves the value or error from a related convertible value

Returns: A reference to this object

◆ operator=() [7/7]

template<typename Value >

template<typename NewValue >
requires std::is_assignable_v<Value, NewValue &&> && std::is_constructible_v<Value, NewValue &&> && (!std::is_same_v<std::remove_cvref_t<NewValue>, Failable<Value>>) && (!std::is_same_v<std::remove_cvref_t<NewValue>, std::error_code>) && (!std::is_error_code_enum_v<NewValue>)

auto xentara::utils::eh::Failable< Value >::operator= ( NewValue && newValue ) const && -> Failable &

noexcept

Assignment operator for a valid value.

Turns the object into a valid value, if it wasn't one already.

Parameters

newValue The value to assign.

Returns: A reference to this object

◆ operator==() [1/3]

template<typename Value >

template<typename RhsValue >
requires std::equality_comparable_with<Value, detail::IfNotFailable<RhsValue>> && (!std::is_same_v<std::remove_cvref_t<RhsValue>, std::error_code>) && (!std::is_error_code_enum_v<RhsValue>)

auto xentara::utils::eh::Failable< Value >::operator== ( const RhsValue & value ) -> bool

Comparison operator for a valid value.

This operator compares the failable to a value. If the object contains an error instead of a valid value, the comparison will always fail, and 'false' is returned.

Parameters

value The value to compare with

Returns: true if the object contains the specified value

◆ operator==() [2/3]

template<typename Value >

auto xentara::utils::eh::Failable< Value >::operator== ( const std::error_code & errorCode ) -> bool

Comparison operator for an error code.

This operator compares the failable to an error code. If the object contains a valid value instead of an error, the error code will be compared to std::error_code().

Parameters

errorCode The error code to compare with

Returns: true if the object contains the specified error code

◆ operator==() [3/3]

template<typename Value >

template<typename Enum >
requires std::is_error_code_enum_v<Enum>

auto xentara::utils::eh::Failable< Value >::operator== ( Enum errorEnum ) -> Failable &

noexcept

Comparison operator for an error enum.

This operator compares the failable to an error enum. If the object contains a valid value instead of an error, the result depends on the type of error enum:

For std::errc, the enum is compared with std::errc(0)
For all other enum types, the result will always be false
Parameters

errorEnum The error enum to compare with

Returns
true if the object contains the specified error enum

◆ throwError()

template<typename Value >

template<std::derived_from< std::system_error > Exception = std::system_error, typename... ExceptionArguments>

auto xentara::utils::eh::Failable< Value >::throwError ( ExceptionArguments &&... exceptionArguments ) const -> void

Throws the error if the object contains an error instead of a value.

Template Parameters

Exception The type of exception to throw.

Parameters

exceptionArguments Additional arguments for the exception constructor. This is usually the [what](std::exception::what) string, but can be any arguments the constructor of Exception takes.

Exceptions

Exception The object contained an error

◆ value() [1/2]

template<typename Value >

auto xentara::utils::eh::Failable< Value >::value ( ) const -> std::add_pointer_t<const Value>

noexcept

Gets the value, if there is one.

Returns: A pointer to the value, or nullptr if the object contains an error instead of a value

◆ value() [2/2]

template<typename Value >

auto xentara::utils::eh::Failable< Value >::value ( ) -> std::add_pointer_t<Value>

noexcept

Gets the value, if there is one.

Returns: A pointer to the value, or nullptr if the object contains an error instead of a value

◆ valueOr() [1/10]

template<typename Value >

auto xentara::utils::eh::Failable< Value >::valueOr ( const Value & fallback ) const && -> Value

noexcept

Gets the value or a fallback value.

Parameters

fallback The value to return if the object contains an error instead of a value

Returns: The value, or fallback if the object contains an error instead of a value

◆ valueOr() [2/10]

template<typename Value >

auto xentara::utils::eh::Failable< Value >::valueOr ( const Value & fallback ) const & -> Value

noexcept

Gets the value or a fallback value.

Parameters

fallback The value to return if the object contains an error instead of a value

Returns: The value, or fallback if the object contains an error instead of a value

◆ valueOr() [3/10]

template<typename Value >

template<std::invocable<> Fallback>

auto xentara::utils::eh::Failable< Value >::valueOr ( Fallback && fallback ) && -> Value

noexcept

Gets the value or generates a fallback value.

Parameters

fallback A callable used to generate the return value if the object contains an error instead of a value

Returns: The value. If the object contains an error instead of a value, fallback is called to generate the return value.

◆ valueOr() [4/10]

template<typename Value >

template<std::invocable<> Fallback>
requires std::is_reference_v<std::invoke_result_t<Fallback &&>> && std::convertible_to<std::invoke_result_t<Fallback &&>, Value&>

auto xentara::utils::eh::Failable< Value >::valueOr ( Fallback && fallback ) -> Value &

Gets the value or generates a reference to a fallback value.

Parameters

fallback A callable used to get a reference to the return value if the object contains an error instead of a value

Returns: The value. If the object contains an error instead of a value, fallback is called to get a reference to the return value.

◆ valueOr() [5/10]

template<typename Value >

template<std::invocable<> Fallback>

auto xentara::utils::eh::Failable< Value >::valueOr ( Fallback && fallback ) const && -> Value

noexcept

Gets the value or generates a fallback value.

Parameters

fallback A callable used to generate the return value if the object contains an error instead of a value

Returns: The value. If the object contains an error instead of a value, fallback is called to generate the return value.

◆ valueOr() [6/10]

template<typename Value >

template<std::invocable<> Fallback>
requires std::is_reference_v<std::invoke_result_t<Fallback &&>> && std::convertible_to<std::invoke_result_t<Fallback &&>, const Value&>

auto xentara::utils::eh::Failable< Value >::valueOr ( Fallback && fallback ) const -> const Value &

Gets the value or generates a fallback value.

Parameters

fallback A callable used to get a reference to the return value if the object contains an error instead of a value

Returns: The value. If the object contains an error instead of a value, fallback is called to get a reference to the return value.

◆ valueOr() [7/10]

template<typename Value >

auto xentara::utils::eh::Failable< Value >::valueOr ( std::reference_wrapper< const Value > fallback ) const -> const Value &

noexcept

Gets a reference to the value or to a fallback value.

Parameters

fallback The value to return if the object contains an error instead of a value

Returns: A reference to the value, or a reference to fallback if the object contains an error instead of a value

◆ valueOr() [8/10]

template<typename Value >

auto xentara::utils::eh::Failable< Value >::valueOr ( std::reference_wrapper< Value > fallback ) -> Value &

noexcept

Gets a mutable reference to the value or to a fallback value.

Parameters

fallback The value to return if the object contains an error instead of a value

Returns: A reference to the value, or a reference to fallback if the object contains an error instead of a value

◆ valueOr() [9/10]

template<typename Value >

auto xentara::utils::eh::Failable< Value >::valueOr ( Value && fallback ) const && -> Value

noexcept

Gets the value or a fallback value.

Parameters

fallback The value to return if the object contains an error instead of a value

Returns: The value, or fallback if the object contains an error instead of a value

◆ valueOr() [10/10]

template<typename Value >

auto xentara::utils::eh::Failable< Value >::valueOr ( Value && fallback ) const && -> Value

noexcept

Gets the value or a fallback value.

Parameters

fallback The value to return if the object contains an error instead of a value

Returns: The value, or fallback if the object contains an error instead of a value

◆ valueOrThrow() [1/2]

template<typename Value >

template<std::derived_from< std::system_error > Exception = std::system_error, typename... ExceptionArguments>

auto xentara::utils::eh::Failable< Value >::valueOrThrow ( ExceptionArguments &&... exceptionArguments ) -> Value &

Gets the value, or throws the error.

Template Parameters

Exception The type of exception to throw.

Parameters

exceptionArguments Additional arguments for the exception constructor. This is usually the [what](std::exception::what) string, but can be any arguments the constructor of Exception takes.

Returns: A reference to the value

Exceptions

Exception the object contained an error

◆ valueOrThrow() [2/2]

template<typename Value >

template<std::derived_from< std::system_error > Exception = std::system_error, typename... ExceptionArguments>

auto xentara::utils::eh::Failable< Value >::valueOrThrow ( ExceptionArguments &&... exceptionArguments ) const -> const Value &

Gets the value, or throws the error.

Template Parameters

Exception The type of exception to throw.

Parameters

exceptionArguments Additional arguments for the exception constructor. This is usually the [what](std::exception::what) string, but can be any arguments the constructor of Exception takes.

Returns: A reference to the value

Exceptions

Exception the object contained an error

Friends And Related Symbol Documentation

◆ failableCast() [1/2]

template<typename RelatedValue , typename Value >

auto failableCast ( const Failable< Value > & failable ) -> Failable<RelatedValue>

This explicit cast function casts the failable to a Failable with a related type. It is equivalent to the conversion constructor, but does not trigger any compiler warnings on narrowing conversions.

◆ failableCast() [2/2]

template<typename RelatedValue , typename Value >

auto failableCast ( Failable< Value > && failable ) -> Failable<RelatedValue>

This explicit cast function casts the failable to a Failable with a related type. It is equivalent to the conversion constructor, but does not trigger any compiler warnings on narrowing conversions.

◆ operator==()

template<typename LhsValue , typename RhsValue >

auto operator==	(	const Failable< LhsValue > &	lhs,
		const Failable< RhsValue > &	rhs
	)		-> bool

Public Member Functions

Related Symbols

Detailed Description

Constructor & Destructor Documentation

◆ Failable() [1/11]

◆ Failable() [2/11]

◆ Failable() [3/11]

◆ Failable() [4/11]

◆ Failable() [5/11]

◆ Failable() [6/11]

◆ Failable() [7/11]

◆ Failable() [8/11]

◆ Failable() [9/11]

◆ Failable() [10/11]

◆ Failable() [11/11]

Member Function Documentation

◆ assign()

◆ error()

◆ hasValue()

◆ operator bool()

◆ operator std::optional< Value >() [1/2]

◆ operator std::optional< Value >() [2/2]

◆ operator*() [1/2]

◆ operator*() [2/2]

◆ operator->() [1/2]

◆ operator->() [2/2]

◆ operator=() [1/7]

◆ operator=() [2/7]

◆ operator=() [3/7]

◆ operator=() [4/7]

◆ operator=() [5/7]

◆ operator=() [6/7]

◆ operator=() [7/7]

◆ operator==() [1/3]

◆ operator==() [2/3]

◆ operator==() [3/3]

◆ throwError()

◆ value() [1/2]

◆ value() [2/2]

◆ valueOr() [1/10]

◆ valueOr() [2/10]

◆ valueOr() [3/10]

◆ valueOr() [4/10]

◆ valueOr() [5/10]

◆ valueOr() [6/10]

◆ valueOr() [7/10]

◆ valueOr() [8/10]

◆ valueOr() [9/10]

◆ valueOr() [10/10]

◆ valueOrThrow() [1/2]

◆ valueOrThrow() [2/2]

Friends And Related Symbol Documentation

◆ failableCast() [1/2]

◆ failableCast() [2/2]

◆ operator==()