Marcin Rzeźnicki at #ScalaUA- Using monads to enforce programming style your Boss likes

Marcin Rzeźnicki explores monadic error handling, Free and Cofree monads, and how he designed a custom monad to solve real-world team constraints.

Marcin Rzeźnicki at #ScalaUA- Using monads to enforce programming style your Boss likes It all started with my boss coming to me - "I don't like EitherT", he said. "All right, you should be using MonadError anyway" - I replied. "Oh, I don't like that even more". So I decided to help him out and everything went south. I ended up wrestling `Free` and `Cofree`, fighting stack overflows, benchmarking trampolines with flame graphs and, finally, rolled up my own monad which I call `Sealed`. I promise I'll put a GitHub link, but for now I am not really proud of it. My boss and my company love it, though. So I thought I could share with you how to use monads to make your boss happy. Topics I'll cover: - monadic error handling and flow control - explore design and implementation of various existing monads in Scala, - learn how to design a lawful monad from scratch and test it, - how to deal with various issues that arise in the process: stack safety, performance implications, - benchmarking with JMH and flame graphs Follow ScalaUA Conference on Twitter: twitter.com/@ScalaUA_Conf