Clojurians Log v2
Clojure programming
Channels
Apps
core-async
2019-01-24T16:24:02.087300Z
How do I convert a collection of channels that will contain only one value (response from a network request) to a collection of those values, while maintaining order?
;; Specifically, I have this
[ch1 ch2 ch3 ...]
;; and want this
[(<! ch1) (<! ch2) (<! ch3) ...]
(map #(<! %) chs), but I don't think the containing go block will work across the function border. Eventually, a coworker came up with this, but it really seems like there should be an easier way that we're not thinking of.
(a/go-loop [acc [] chs chs]
(if (seq chs)
(let [ret (<! (first chs))]
(recur (conj acc ret) (rest chs)))
acc))
2019-01-24T16:46:02.087500Z
clojure.core.async/merge
2019-01-24T16:56:25.088200Z
I looked at that, but it uses alts!, so order is lost.
bertofer 2019-01-24T16:58:18.088600Z
I think you could use core.async/map (https://clojuredocs.org/clojure.core.async/map)
2019-01-24T16:59:19.088800Z
Oh, I bet you're right!
2019-01-24T16:59:58.089100Z
Yay!
(<!! (a/map vector [(a/go (Thread/sleep 1000) 1) (a/go 2)]))
[1 2]
ghadi 2019-01-24T17:49:49.090500Z
in favor of transducers on the channel
alexmiller 2019-01-24T17:50:09.091Z
no, it’s not
ghadi 2019-01-24T17:50:10.091100Z
whoops, no it isn't: that's map< and map>