I think this has been a theme with him the past couple of years. He's gone into Haskell territory, and has recently been an extremely vocal proponent of immutab

I think this has been a theme with him the past couple of years. He's gone into Haskell territory, and has recently been an extremely vocal proponent of immutable structures (coming from the man behind some pretttty fast programs, that's a nice cold shower for a lot of people), and generally higher-level thinking. I think this is a consequence of a lot of these languages getting a lot nicer tooling recently, as well as other FP ideas being pulled into newer languages.