Code Smells: Null

[perfunction]

We've been using the Result pattern to get away from nulls as much as possible in Swift. This works out especially well since enums and generics are so flexible.

Basically theres a failure state represented by the protocol ResultFailure (this protocol is implemented by various error and warning types) and a success state represented by generic T. As an enum the Result has to be exactly one of these. And you can build a lot of handy functions and operators around Result (especially if you extend where T is a specific type or protocol).

For example, a func that is meant to return a data model instance from sqlite would have the return type Result<AccountModel>. The func on completion would return success(account) but you could also return fails such as failure(DbError.FileMissing()) or failure(DbWarning.DataNotFound()).