Hi everyone. Here is a modified example from https://clojuredocs.org/clojure.core.async/pub.

(def src (chan 1))
(def publisher (pub src :topic))

(def alice (chan 1))
(def bob (chan 1))
(def clyde (chan 1))

(sub publisher :celebrity-gossip alice)
(sub publisher :space-x bob)
(sub publisher :space-x clyde)

(def a-alice (atom []))
(def a-bob (atom []))
(def a-clyde (atom []))

(go-loop [heard (<! alice)] (reset! a-alice conj (str "alice heard: " heard)))
(go-loop [heard (<! bob)] (reset! a-bob (str "bob heard: " heard)))
(go-loop [heard (<! clyde)] (reset! a-clyde (str "clyde heard: " heard)))

(put! src {:topic :celebrity-gossip :data "omg she's prego!"})
(put! src {:topic :space-x :data "omg we're landing!"})

Why does @a-alice return []?

@neil.barrett16 i haven't looked at this too carefully yet, but do you mean swap! instead of reset! for the atoms?

yes, sorry

can you rerun it and see if the result is still wrong?

Perfect! Silly of me. Thanks a lot.

Of course! I used conj with reset!.

Is there any way to get println to work in a go or go-loop in Clojupyter? Does it work in a standard repl?

printing in background threads works with a standard REPL, but not always with nREPL-based things (Not sure what Clojupyter uses) standard REPL meaning clojure.main

Thanks ghadi.

another alternative to printing in background threads is passing things a log channel

data > dead text

Great! I'll try that.

How would I print from the log channel? Won't it have to be in a go-loop?

Or would I write to a file?

This works with Clojupyter:

(def src (chan 1))
(def publisher (pub src :topic))

(def alice (chan 1))
(def bob (chan 1))
(def clyde (chan 1))

(sub publisher :celebrity-gossip alice)
(sub publisher :space-x bob)
(sub publisher :space-x clyde)

(def log-atom (atom nil))
(add-watch log-atom :key (fn [_ _ _ ns] (println ns)))

(defn log [msg]
    (reset! log-atom msg))

(go-loop [] 
    (when-let [heard (<! alice)] 
        (log (str "alice heard: " heard))
        (recur)))
(go-loop [] 
    (when-let [heard (<! bob)] 
        (log (str "bob heard: " heard))
        (recur)))
(go-loop [] 
    (when-let [heard (<! clyde)] 
        (log (str "clyde heard: " heard))
        (recur)))

(put! src {:topic :celebrity-gossip :data "omg she's prego!"})
(put! src {:topic :space-x :data "omg we're landing!"})
(put! src {:topic :space-x :data "omg we're launching!"})
(close! src)