Event Sourcing & Functional Programming - a pair made in heaven

Room 5 - BestWestern

While reading blogs or attending conferences, you might have heard about Event Sourcing. But didn’t you get this feeling, that while there is a lot of theory out there, it is really hard to see a hands-on example? And even if you find some, those are always orbiting around Object Oriented concepts? Greg Young once said "When we talk about Event Sourcing, current state is a left-fold of previous behaviors. Nothing new to Functional Programmers". If Functional Programming is such a natural concept for event sourced systems, shouldn’t they fit together on a single codebase? In this talk we will quickly introduce Event Sourcing (but without going into details), we will introduce some functional concepts as well (like State monad) Armoured with that knowledge we will try to transform sample ES application (OO-style, tightly coupled with framework) to frameworkless, FP-style solution). Talk is targeted for beginner and intermediate audience. Examples will be in Scala but nothing fancy - normal syntax.