Clojurians Log v2

I’m experimenting with self-hosted cljs in the browser, bootstrapped with shadow-cljs. I’m evaluating cljs typed into a textarea, eval’ed with the on-change event (debounced by a few hundred milliseconds). It works fine mostly, however, I’ve noticed that when typing in forms/expressions that yield infinite lazy sequences, the browser seizes up and stops responding. For example, typing (range) causes this behavior. Are there any good strategies for dealing with this?

don't eval infinite sequences? 😛

I'm guessing you call pr-str or so on the result?

I use cljs/eval-str and show the result in a div

The problem I have is that I can’t prevent users of the web-app from evaluating infinite series that they’ve input into the textarea…

Is there a way to force-kill the infinite evaluation? (like hitting Ctrl-C when hitting an infinite loop in a command-line REPL?)

well HOW do you display it in a div? I assume pr-str? THAT is were your infinite sequence is realized

so that is the problem you need to solve

eg. you can set *print-length* to limit the amount of items printed

not exactly sure how you do that in self-hosted but something to look into

No, I simply do this:

(defonce evaluated-output (r/atom nil))

(defn compile-it [code]
  (let [options  {:eval cljs/js-eval
                  :load (partial boot/load c-state)}
        callback (fn [result]
                   (reset! evaluated-output (:value result)))]
    (cljs/eval-str c-state code "[demo-bootstrap-cljs]" options callback)))

[:pre>code "Output: " [:strong (str @evaluated-output)]]

(str @evaluated-output)

Yes, I see what you’re saying now

should be using pr-str in either case but str is the same in this case

(binding [*print-length* 5] (pr-str @evaluated-output)) might be enough

I’m not clear what the difference it, but I will put pr-str then

pr-str produces EDN output

str calls toString (which will not always be EDN)

That works perfectly! You’re awesome, @thheller Thanks so much!!!

Is there any way to get shadow-cljs to watch and hot-reload changes to index.html?

no

Thanks! Some note of this in the documentation would be great - it's not so clear what "monitor your source files and recompile them automatically" encompasses exactly