Applicative validation in Scala

March 30, 2016

One of the first functional data structures I reach for when writing code that interacts with a person or another system is Validation. It allows me to accumulate, parse, transform, and verify input in a type-safe and parallelizable operation.

In this talk, we look at Validation: how to use it, why it works, and where in category theory it comes from. We'll see how to use the implementations provided by Scalaz and Cats, as well as how to roll our own from scratch.