From 4dfb55987222f961ea60db7026fcf281a9f493f7 Mon Sep 17 00:00:00 2001
From: Oleksandr Yakushev <alex@bytopia.org>
Date: Mon, 26 Aug 2024 21:51:50 +0300
Subject: [PATCH] Add native implementation for IKVReduce in
 toucan2.instance.Instance (#174)

Without this, if kv-reduce is called on an Instance, the code follows the slow
unoptimal path of calling 'reduce' on the map and constructing MapEntries.
---
 src/toucan2/instance.clj       | 5 +++++
 test/toucan2/instance_test.clj | 5 +++++
 2 files changed, 10 insertions(+)

diff --git a/src/toucan2/instance.clj b/src/toucan2/instance.clj
index a1fd05d..6f73676 100644
--- a/src/toucan2/instance.clj
+++ b/src/toucan2/instance.clj
@@ -13,6 +13,7 @@
   current value and their model is the same."
   (:refer-clojure :exclude [instance?])
   (:require
+   clojure.core.protocols
    [potemkin :as p]
    [pretty.core :as pretty]
    [toucan2.protocols :as protocols]
@@ -137,6 +138,10 @@
   (asTransient [_this]
     (->TransientInstance model (transient m) mta))
 
+  clojure.lang.IKVReduce
+  (kvreduce [_this f init]
+    (clojure.core.protocols/kv-reduce m f init))
+
   protocols/IModel
   (protocols/model [_this]
     model)
diff --git a/test/toucan2/instance_test.clj b/test/toucan2/instance_test.clj
index e99d17e..b8cea7c 100644
--- a/test/toucan2/instance_test.clj
+++ b/test/toucan2/instance_test.clj
@@ -429,3 +429,8 @@
           m2 (assoc m :location nil)]
       (is (= {:location nil}
              (protocols/changes m2))))))
+
+(deftest ^:parallel reduce-kv-test
+  (testing "instance supports IKVReduce iteration natively"
+    (let [instance (instance/instance ::foo (zipmap (range 100) (range)))]
+      (is (= 100 (.kvreduce instance (fn [c _ _] (inc c)) 0))))))