From afbb8d284349c46f8c5cd999e21f95c62572fda9 Mon Sep 17 00:00:00 2001
From: Asko Nõmm <asko@nmm.ee>
Date: Wed, 24 Sep 2025 10:09:05 +0300
Subject: Improve performance of the $ macro.

---
 src/dompa/nodes.cljc |  1 -
 src/dompa/utils.cljc | 56 +++++++++++++++++++++++++++++++---------------------
 2 files changed, 34 insertions(+), 23 deletions(-)

(limited to 'src/dompa')

diff --git a/src/dompa/nodes.cljc b/src/dompa/nodes.cljc
index dfd93bc..295e755 100644
--- a/src/dompa/nodes.cljc
+++ b/src/dompa/nodes.cljc
@@ -62,7 +62,6 @@
     - `:wbr`
   "
   ([nodes]
-   (prn "nodes: " nodes)
    (->html nodes {:void-nodes default-void-nodes}))
   ([nodes {:keys [void-nodes]}]
    (-> (node->html-reducer-fn void-nodes ->html)
diff --git a/src/dompa/utils.cljc b/src/dompa/utils.cljc
index 74185b5..0e17875 100644
--- a/src/dompa/utils.cljc
+++ b/src/dompa/utils.cljc
@@ -1,5 +1,6 @@
 (ns dompa.utils
-  (:require [dompa.nodes :as nodes]))
+  (:require [dompa.nodes :as nodes]
+            [criterium.core :as c]))
 
 (defmacro defhtml
   {:clj-kondo/lint-as 'clojure.core/defn}
@@ -8,35 +9,46 @@
     `(defn ~name ~args
        (nodes/->html (vector ~@elements)))))
 
-(defn- flattench [children]
-  (mapcat #(if (sequential? %) (flattench %) [%]) children))
+(defn flattench-xf []
+  (fn [rf]
+    (letfn [(step [result input]
+              (if (sequential? input)
+                (reduce step result input)                  ;; recursively reduce over nested seq
+                (rf result input)))]                        ;; apply rf with accumulator + value
+      (fn
+        ([] (rf))                                           ;; init
+        ([result] (rf result))                              ;; completion
+        ([result input] (step result input))))))            ;; step
+
+(defn flattench [children]
+  (into [] (flattench-xf) children))
 
 (defmacro $
   {:clj-kondo/lint-as 'clojure.core/list}
   [name & opts]
   `(if (string? ~name)
      {:node/name  :dompa/text
-      :node/value (apply str ~name ~opts)}
-     (let [name# ~name
-           opts-list# (list ~@opts)
-           first-opt# (first opts-list#)
+      :node/value (apply str ~name ~@opts)}
+     (let [opts# (list ~@opts)
+           first-opt# (first opts#)
            attrs?# (and (map? first-opt#)
                         (not (contains? first-opt# :node/name)))
            attrs# (if attrs?# first-opt# {})
-           children# (if attrs?# (rest opts-list#) opts-list#)]
-       (merge
-         {:node/name name#}
-         (when attrs?# {:node/attrs attrs#})
-         (when (seq children#) {:node/children (flattench children#)})))))
+           children# (if attrs?# (rest opts#) opts#)]
+       (cond-> {:node/name ~name}
+               attrs?# (assoc :node/attrs attrs#)
+               (seq children#) (assoc :node/children (flattench children#))))))
+
+(defn bench-n []
+  (c/quick-bench
+    (dotimes [_ 1500]
+      ($ :div {:class "container"}
+          (map #($ %) ["a" "b" "c"])
+          ($ "hello world")))))
 
-(defhtml page [who]
-  ($ :div {:class "test"}
-    ($ "hello world")
-    (let [n "who"]
-      ($ n))
-    (for [x ["1" "2" "3"]]
-      ($ x))
-    ($ who)
-    (mapv #($ %) ["a" "b" "c"])))
+(defhtml test-page []
+  ($ :div
+      (map #($ %) ["a" "b" "c"])
+      ($ "hello world")))
 
-(page "world")
\ No newline at end of file
+(test-page)
-- 
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