Rust error handling is nice but obligatory. Which makes it sometimes plenty of code.
Functions return values of type Result that is "enumeration". In Rust enumeration means complex value that has alternatives and that alternative is shown with a tag.
Result is defined as Ok or Err. The definition is generic, and both alternatives have
| # Rust Error Handling Cheatsheet - Result handling functions | |
| | What to do with | | Code | | |
| | Ok t:T | Err e:E | r: Result<T, E> | Description | |
| |-------------------------------|---------------------------------------------|-----------------------------------|---------- | |
| | ## mapping result to result | | | | |
| | t -> Result::Ok(t2) | e -> e2 | r.map_or_else(|e| g(e), |t| f(t)) | Map both Ok and Err with function, function can not return Result (errror), note that Err mapping function is first (it is considered as a default like in the map_or) | |
| | t -> t2 (Ok or Err) | Literal (default) | r.map_or(literal, |t| f(t)) | Map with literal but if error, use default literal, mapping function can be a |
