> However, unlike our OOP example, existing code that uses the Logger type and log function cannot work with this new type. There needs to be some refactoring,

> However, unlike our OOP example, existing code that uses the Logger type and log function cannot work with this new type. There needs to be some refactoring, and how the user code will need to be refactored depends on how we want to expose this new type to the users. This is odd to me. There are solutions to make data types extensible in haskell, but for example in purescript you'd just use a record. But more importantly, why would you want existing functions to use the new type? Why not just pass the _logger from FileLogger in? The existing functions can't use the _flush ability anyway (in both OOP and FP cases)