Clojurians Log v2

i tried to use stdin in nodejs once. it is a mess.

(js/process.stdin.on "data" (fn [data] (println "From stdin: " (str data))))

You can put that in a .cljs file and call echo ‘something’ | nbb myfile.cljs

Basically, process.stdin gives you a Stream object and you can attach callbacks for certain events on that.

https://nodejs.org/api/process.html#processstdin

Thank you! That API feels weird but I guess we’ll go with it 😁

Yep, that’s typical node weirdness. 🙂 No blocking is good so it’s callbacks or sugar around it like promises

I think there’s a promises based version of the stream api

Uhhhmm kinda yes. At least there’s pipeline function that can construct streaming pipelines. Here’s a stupid example that just pipes stuff from stdin to stdout. 😄

(ns demo
  (:require ["stream/promises" :as sp]))

(sp/pipeline js/process.stdin js/process.stdout)

But you could add there transform steps and whatnot

Kinda weird, kinda cool.

Heh, yeah you can do this kind of things

(ns demo
  (:require ["stream/promises" :as sp]
            ["stream" :as s]))

(def upcase
  (s/Transform. #js{:transform (fn [chunk enc cb]
                                 (cb nil (clojure.string/upper-case (str chunk))))}))

(sp/pipeline js/process.stdin upcase js/process.stdout)

And now I can upcase enormous amounts of text with very low memory footprint.

Thanks! Use case is a build script that fetches data, formats it as a clojure file str, and was hoping to use zprint api to format it as a file and write it to the fs. Worst case can use it from an npm wrapper after the build script https://www.npmjs.com/package/zprint-wrapper

Didn't realize you were on vacation, sorry for the interruption!

Oh not at all, it would be ridiculous if people couldn't ask questions here if I were on vacation. It's up to me to answer or not ;)