Simplify with-let and tweak performance

src/reagent/ratom.clj

@@ -17,15 +17,7 @@
 (defmacro with-let [bindings & body]
   (assert (vector? bindings))
   (let [v (gensym "bind-v")
-        bs (->> bindings
-                (map-indexed (fn [i x]
-                               (if (even? i)
-                                 x
-                                 (let [pos (quot i 2)]
-                                   `(if (> (alength ~v) ~pos)
-                                      (aget ~v ~pos)
-                                      (aset ~v ~pos ~x))))))
-                vec)
+        key (str v)
         [forms destroy] (let [fin (last body)]
                           (if (and (list? fin)
                                    (= 'finally (first fin)))
@@ -35,18 +27,20 @@
                       `(cljs.core/js-obj))
         asserting (if *assert* true false)]
     `(let [destroy-obj# ~destroy-obj
-           ~v (reagent.ratom/get-cached-values (quote ~v) destroy-obj#)]
+           ~v (reagent.ratom/with-let-value ~key destroy-obj#)]
        (when ~asserting
          (when-some [c# reagent.ratom/*ratom-context*]
-           (when (== (.-ratomGeneration c#)
-                     (.-generation ~v))
+           (when (== (.-generation ~v) (.-ratomGeneration c#))
              (d/error "Warning: The same with-let is being used more than once in the same reactive context."))
            (set! (.-generation ~v) (.-ratomGeneration c#))))
-       (let ~bs
-         (let [destroy# ~destroy
-               res# (do ~@forms)]
-           (when-not (nil? destroy#)
-             (if (reagent.ratom/reactive?)
-               (set! (.-destroy destroy-obj#) destroy#)
-               (destroy#)))
-           res#)))))
+       (when (zero? (alength ~v))
+         (aset ~v 0 (let ~bindings
+                      (fn []
+                        (let [res# (do ~@forms)]
+                          (when-some [destroy# ~destroy]
+                            (if (reagent.ratom/reactive?)
+                              (when (nil? (.-destroy destroy-obj#))
+                                (set! (.-destroy destroy-obj#) destroy#))
+                              (destroy#)))
+                          res#)))))
+       ((aget ~v 0)))))

src/reagent/ratom.cljs

@@ -1,6 +1,6 @@
 (ns reagent.ratom
   (:refer-clojure :exclude [atom])
-  (:require-macros [reagent.ratom])
+  (:require-macros [reagent.ratom :refer [with-let]])
   (:require [reagent.impl.util :as util]
             [reagent.debug :refer-macros [dbg log warn dev?]]))
 
@@ -45,6 +45,15 @@
               (conj (if (nil? captured) #{} captured)
                     derefable))))))
 
+(def reaction-counter 0)
+
+(defn reaction-key [r]
+  (if-some [k (.-reaction-id r)]
+    k
+    (->> reaction-counter inc
+         (set! reaction-counter)
+         (set! (.-reaction-id r)))))
+
 (defn- check-watches [old new]
   (when debug
     (swap! -running + (- (count new) (count old))))
@@ -131,8 +140,10 @@
                                      (dissoc cached-reactions key))
                                (when (some? obj)
                                  (set! (.-reaction obj) nil))
-                               (when (some-> destroy .-destroy some?)
-                                 (.destroy destroy))))
+                               (when-not (or (nil? destroy)
+                                             (nil? (.-destroy destroy)))
+                                 (.destroy destroy))
+                               nil))
             v (-deref r)]
         (set! cached-reactions (assoc cached-reactions key r))
         (when (some? obj)
@@ -269,20 +280,10 @@
 
 ;;; with-let support
 
-(def reaction-counter 0)
-
-(defn reaction-key []
-  (when-some [c *ratom-context*]
-    (if-some [k (.-reaction-id c)]
-      k
-      (->> reaction-counter inc
-           (set! reaction-counter)
-           (set! (.-reaction-id c))))))
-
-(defn get-cached-values [key destroy]
-  (if-some [k (reaction-key)]
-    (cached-reaction #(array)
-                     [k key] nil destroy)
+(defn with-let-value [key destroy]
+  (if-some [c *ratom-context*]
+    (cached-reaction array [(reaction-key c) key]
+                     nil destroy)
     (array)))
 
 
@@ -357,7 +358,7 @@
     (when (== dirtyness maybe-dirty)
       (let [ar auto-run]
         (set! auto-run nil)
-        (doseq [w watching]
+        (doseq [w watching :while (== dirtyness maybe-dirty)]
           (when (and (instance? Reaction w)
                      (not (-check-clean w)))
             (._try-run this w)))
@@ -466,7 +467,7 @@
     (-write writer ">"))
 
   IHash
-  (-hash [this] (goog/getUid this)))
+  (-hash [this] (reaction-key this)))
 
 
 ;;; Queueing
@@ -596,9 +597,13 @@
       (set! perf-check 0)
       (let [nite 100000
             a (atom 0)
-            mid (make-reaction (fn [] (inc @a)))
+            f (fn []
+                ;; (with-let [x 1])
+                (quot @a 10))
+            mid (make-reaction f)
             res (make-reaction (fn []
                                  (set! perf-check (inc perf-check))
+                                 ;; @(track f)
                                  (inc @mid))
                                :auto-run true)]
         @res

test/reagenttest/testratomasync.cljs

@@ -134,19 +134,19 @@
              
       (reset! a 2)
       (sync)
-      (is (= @b-changed 3))
+      (is (<= 2 @b-changed 3))
       (is (= @c-changed 1))
       (is (= @res (+ 10 @a)))
              
       (reset! a 3)
       (sync)
-      (is (= @b-changed 3))
+      (is (<= 2 @b-changed 3))
       (is (= @c-changed 2))
       (is (= @res (+ 10 @a)))
              
       (reset! a 3)
       (sync)
-      (is (= @b-changed 3))
+      (is (<= 2 @b-changed 3))
       (is (= @c-changed 2))
       (is (= @res (+ 10 @a)))