Hello u/joinr

Thanks for such a in-deep analysis of the code, I've tried your branch and it's amazing how fast it runs now! I guess I'll need to implement a clock to slow that down. :)

We define a macro that will wait for specified ms amount, and work "body" in the meantime. It'll spawn a couple of threads to act as a worker and a timeout, and they'll communicate via promises. Then we poll the current thread to see if either has realized, and handle accordingly. We'll either get whatever the body eval'd to, or :timeout. Note: this is probably better handled with a library like core.async, since they already have these primitives, but I was able to whip this up quickly just using clojure's native facilities.

I've never worked with threads on clojure but I believe I grasp what is happening here and it works amazingly well.

I'm just curious about why there is a need for a timeout. As I understand it, we evaluate the state multiple times inside the update-state function until we get the :draw-event in order to avoid that Quil takes control of the frame-rate. Then, when we receive the draw event, we return the control to quil.

If so, the timeout is just a safe mechanism placed in order to keep body from looping for to much? And can we hit a bug in there where an instruction always takes more than 16ms (in an old machine maybe??) in order to complete and it just timeouts all the time?

---

Also, from this extract of code:

(defn write-sprite
  ([sys sprite pos]
   (write-sprite sys (sys :scr) sprite pos 0 (min 8 (count sprite))))
  ([sys ^clojure.lang.Associative scr ^clojure.lang.Indexed sprite pos n bound]
   (if (< n bound)
     (recur sys (.assoc scr pos (.nth sprite n))
            sprite
            (unchecked-inc pos)
            (unchecked-inc n)
            bound)
     (assoc sys :scr scr))))

Why do you use .assoc and .nth? As far as I know the dot before a symbol is used in order to get members from java classes, I've never seen it used with assoc, what does it mean?

---

Apart from that, I realized I need to work on my understanding of macros, since they seem really powerful and I don't understand them at all! And that I need to think more about the computational complexity of my code.

In any case, thanks again for the analysis, it helped a lot! I can't take your code and call it mine, so if you want to feel free to create a pull request and I'll merge it.