Struct nebula::util::expected

template <typename T, typename E>

ClassList > nebula > util > expected

A poor man's backport of C++23's std::expected. More...

• #include <expected.hpp>

Public Functions

Type	Name
E	error () Retrieve the error, or throw bad_expected_access if a value is contained.
E	error_or (const E & default_) Return the contained error, or, if a value is contained, return the given default_ instead.
	expected (const T & value)
	expected (const E & error)
bool	has_value () Whether the expected instance holds a value (as opposed to an error). Call this before trying to access values via value() .
T	value () Retrieve the value, or throw bad_expected_access if an error is contained.
T	value_or (const T & default_) Return the contained value, or, if an error is contained, return the given default_ instead.
T	value_or_throw (const std::string & error_msg) If the instance has a value, return the value, else throw std::runtime_error(error_msg)
T	value_or_throw () If the instance has a value, return the value, else throw the stored error instance.

Detailed Description

At any given time, holds exactly one of: expected value, or error value. Provides functions for easy exception handling.

More info here: https://en.cppreference.com/w/cpp/utility/expected

Template parameters:

• T Type of the expected value
• E Error type

Public Functions Documentation

function error

Retrieve the error, or throw bad_expected_access if a value is contained.

inline E nebula::util::expected::error () 

Returns:

The error of type E

---

function error_or

Return the contained error, or, if a value is contained, return the given default_ instead.

inline E nebula::util::expected::error_or (
    const E & default_
) 

Returns:

The contained error, if any, else default_

---

function expected [1/2]

inline nebula::util::expected::expected (
    const T & value
) 

---

function expected [2/2]

inline nebula::util::expected::expected (
    const E & error
) 

---

function has_value

Whether the expected instance holds a value (as opposed to an error). Call this before trying to access values via value() .

inline bool nebula::util::expected::has_value () 

Returns:

True if a value is contained, false if an error is contained

---

function value

Retrieve the value, or throw bad_expected_access if an error is contained.

inline T nebula::util::expected::value () 

Returns:

The value of type T

---

function value_or

Return the contained value, or, if an error is contained, return the given default_ instead.

inline T nebula::util::expected::value_or (
    const T & default_
) 

Returns:

The contained value, if any, else default_

---

function value_or_throw [1/2]

If the instance has a value, return the value, else throw std::runtime_error(error_msg)

inline T nebula::util::expected::value_or_throw (
    const std::string & error_msg
) 

Parameters:

• error_msg The message to be included in the thrown exception

Returns:

The value

---

function value_or_throw [2/2]

If the instance has a value, return the value, else throw the stored error instance.

inline T nebula::util::expected::value_or_throw () 

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The documentation for this class was generated from the following file nebula_common/include/nebula_common/util/expected.hpp