Actually, when I said 'update', I meant the functions that in standard languages that would modify the existing structure return a new one, but it's great you f

Actually, when I said 'update', I meant the functions that in standard languages that would modify the existing structure return a new one, but it's great you found update-in. That's a beautiful function. There's also assoc-in, which is basically just a more specialized assoc-in. I've built cyclical graphs in Clojure. The simplest form looks like {:nodes #{:a :b :c} :edges {:a #{:b} :b #{:c} :c #{:a}}} (for non-clojurians, {} is a map, and #{} is a set)