Klaas Pieter Annema talks about what he learned from his attempts to learn functional programming. He explains the syntax and explains the concepts of generics, closures, promises and functors. He also shows how the Argo JSON library makes parsing JSON very simple using functional programming. Recorded at the CocoaHeadsNL meetup of February 14th, 2018 at the office of Xebia in Hilversum.