As of March 2020, School of Haskell has been switched to read-only mode. Monad transformers are the standard way to extend monads. The transformers package defines monad transformers. StateT, one of the representative monad transformers, has three parameters: newtype StateT s m a = StateT { runStateT :: s -> m (a, s) }The second parameter m allows you to add a new type of effect while preserving t

As of March 2020, School of Haskell has been switched to read-only mode. This is an FP Complete coding standards document written by Michael Snoyman. I'm exposing it to the outside world, but some of the prose definitely maintains the coding standard approach. This piece is highly opinionated, and I'm sure some people will have different thoughts on how to do this. There is much debate in the Hask