On Tuesday, 18 December 2018 at 10:19:14 UTC, Russel Winder wrote: > Clojure is but you have to work hard for that, the initial > language is effectively pure. https://ideone.com/y8KWja clearly it isn't, its site only claims that most code happens to be pure, but it looks like it's not checked in any way and not sure if purity can be even checked there.