C++17 version of Rust's Result. The implementation is motivated by approach used in Oktal's Result.
the examples how to use the supported operations are placed in result_test.cpp file in the test subdirectory.
| Operation | Description |
|---|---|
| is_ok | returns true if the result is Ok |
| is_err | returns true if the result is Err |
| ok | converts from Result<T, E> to std::optional<T> |
| err | converts from Result<T, E> to std::optional<E> |
| expect | returns the contained Ok value |
| expect_err | returns the contained Err value |
| map | maps a Result<T, E> to Result<U, E> by applying a function to a contained Ok value, leaving an Err value untouched |
| map_err | maps a Result<T, E> to Result<T, F> by applying a function to a contained Err value, leaving an Ok value untouched |
| map_or | applies a function to the contained value (if any), or returns the provided default (if not) |
| map_or_else | maps a Result<T, E> to U by applying a function to a contained Ok value, or a fallback function to a contained Err value |
| and (as operator&&) | returns res if the result is Ok, otherwise returns the Err value |
| and_then | calls op if the result is Ok, otherwise returns the Err value |
| or (as operator||) | returns res if the result is Err, otherwise returns the Ok value |
| or_else | calls op if the result is Err, otherwise returns the Ok value |
| unwrap | returns the contained Ok value |
| unwrap_err | returns the contained Err value |
| unwrap_or | returns the contained Ok value or a provided default |
| unwrap_or_default | returns the contained Ok value or a default |
| unwrap_or_else | returns the contained Ok value or computes it from a closure |
| contains | returns true if the result is an Ok value containing the given value |
| contains_err | returns true if the result is an Err value containing the given value |
| transpose | transposes a Result<std::optional<T>, E> into a std::optional<Result<T, E>>. Ok(std::nullopt) will be mapped to std::nullopt |
| equality/inequality operators | compares the euality/inequality of two Results or Result and Err or Result and Ok |