First mistake of functional programmers approaching oo: thinking it's about the objects. It's mostly about decomposition and message passing. If one fixates on

First mistake of functional programmers approaching oo: thinking it's about the objects. It's mostly about decomposition and message passing. If one fixates on mapping reality on objects they are in for a bag of hurt. And what's message passing if not functions? But that doesn't make it functional programming. The method of decomposing problems and composing code to build solutions is the key.