std::expected<T,E>::or_else
Min standard notice:
If *this contains an unexpected value, invokes f with the unexpected value of *this as the argument and returns its result. Otherwise, returns a std::expected object that represents an expected value.
# Declarations
Primary template
template< class F >
constexpr auto or_else( F&& f ) &;
(since C++23)
template< class F >
constexpr auto or_else( F&& f ) const&;
(since C++23)
template< class F >
constexpr auto or_else( F&& f ) &&;
(since C++23)
template< class F >
constexpr auto or_else( F&& f ) const&&;
(since C++23)
void partial specialization
template< class F >
constexpr auto or_else( F&& f ) &;
(since C++23)
template< class F >
constexpr auto or_else( F&& f ) const&;
(since C++23)
template< class F >
constexpr auto or_else( F&& f ) &&;
(since C++23)
template< class F >
constexpr auto or_else( F&& f ) const&&;
(since C++23)
# Parameters
f: a suitable function or Callable object that returns a std::expected
# Notes
Feature-test macro Value Std Feature __cpp_lib_expected 202211L (C++23) Monadic functions for std::expected
# Example
This section is incompleteReason: no example
# Defect reports
| DR | Applied to | Behavior as published | Correct behavior |
|---|---|---|---|
| LWG 3938 | C++23 | the expected value was obtained by value()[1] | changed to **this |
| LWG 3973 | C++23 | the expected value was obtained by **this[2] | changed to val |