How can I view a subset of the clojure tree (Hash Map) for changes?

Question

I would like to follow the changes in different parts of the Clojure hash map (access via STM ref), which forms a fairly large tree, and with changes in those parts I would like to call some registered listeners. How to do this in Clojure, since I understand that add-watch only works with the whole link?

Answer 1

I will also observe the whole tree and check the subsets with the entrance. Can you quickly check if a subtree has been changed using an identical one? test against the previous state. Sort of

(defn change-tester [tree path]
  (let [orig (get-in tree path)]
    (fn [tree]
      (not (identical? (get-in tree path) orig)))))

I don’t use observers often, so I don’t know the syntax, but you can somehow attach this function, I'm sure.

Answer 2

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Answer 3

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