u/DavidRaabin r/ProgrammingLanguages • Recommends
On “If-fail-else Construct”
You ca re-think your code in a more functional way. First the function `user_exists` and `get_user` are not needed. Instead you provide just a `get_user` that can return an optional user. So it either is a user or none.
Then you could filter an option by a predicate `is_banned`. And finally you can do what you need with a user. `login` and other stuff.
Here is an F# inspired code.
```
User.get "fred"
|> Option.filter User.isBanned
|> Option.map User.login
|> Option.map Log.user
|> Option.map User.doSomethingWithUser
```
Instead of `Option` it also could be a `Result`. Haskell names it `Either`. Scott Waschlin named it Railway oriented programming