// dodge a noisy nullReferenceException

if (message["symbol"] == null) break;

>> gd script vs csharp differences

>> godot csharp basics

(let [x "hi there"
      n 2]
      ;; (await (Godot.Object/ToSignal 2 "timeout"))
      ;; (await (Godot.Object/ToSignal (.CreateTimer (Godot.Engine/GetMainLoop) 2 true) "timeout"))
      (a/timeout n (fn []
                     (a/log "waited for n" n x)))
    (a/log "fired right away" x))

;; 1
    (swap! bullets
           (fn [bs]
             (let [;; add new bullet to front
                   new-bs               (concat
                                          ;; Storing weak refs b/c these can be freed upon
                                          ;; impact with enemies
                                          [(Godot.Object/WeakRef bullet-inst)]
                                          bs)
                   ;; split via max-bullets
                   [to-keep to-destroy] (split-at max-bullets new-bs)
                   to-keep              (vec to-keep)]

               ;; destroy excess bullets
               (doall
                 (for [b to-destroy] (bullet/kill b)))

               ;; return new list of bullets
               to-keep)))

;; vs 2
    (if (> (- (count @bullets) 1) @current-bullet)
      (let [to-remove (get @bullets @current-bullet)]
        (if to-remove
          (do
            (a/log "to-remove" to-remove)
            (a/log "a/obj" (a/obj to-remove)))
          (a/log "no to-remove"))
        (when (and to-remove (a/obj to-remove))
          (a/log "destroying bullet!" to-remove)
          (a/destroy to-remove)))
      (swap! bullets #(conj % bullet-inst)))

    (swap! current-bullet
           #(if (> % max-bullets) 0 (inc %)))