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missionary 2025-04-25
Erich Ocean 2025-04-25T23:15:56.444929Z
I've got a bit of code that's puzzling me. Full example (copy and paste to run it, it's self-contained):
(do
(def value-atom (atom [true 1]))
(def [true nil]
(reset! continue-atom true) ; SHOULD UNSUBSCRIBE [false 1]
(reset! continue-atom false)
; EXPECT , ACTUAL [true nil]
(reset! value-atom [false 2])
; ASSERT => [false 2], should NOT subscribe to
(cancel!)) Erich Ocean 2025-04-25T23:19:05.308899Z
Since loop/recur reuses the stack, my expectation is that subscription on <continue-sig would be unsubscribed when recur is called.
leonoel 2025-04-27T08:11:07.905439Z
loop/recur does reuse the current stack frame, but a new stack frame is recreated (forked) whenever a m/?< switches.
If <continue-sig were unsubscribed on recur, the behavior would not be the same as if the loop was unrolled
Erich Ocean 2025-04-27T16:15:01.101129Z
Thanks, I'll think in terms of loop unrolling going forward.
Erich Ocean 2025-04-25T23:32:42.882089Z
Another oddity: (cancel!) isn't printing out the missionary.Cancelled exception like it does in other scenarios. o_0