Improve clojure-ts--node-child-skip-metadata performance by ~6x

CHANGELOG.md

@@ -3,6 +3,7 @@
 ## main (unreleased)
 
 - Add project root detection for ClojureCLR project.
+- Improve performance for imenu, font-lock and indentation.
 
 ## 0.6.0 (2025-12-02)
 

clojure-ts-mode.el

@@ -1001,12 +1001,16 @@ If there is no namespace, returns nil."
        (string-equal expected-symbol-name (clojure-ts--named-node-text node))))
 
 (defun clojure-ts--node-child-skip-metadata (node n)
-  "Return the Nth child of NODE like `treesit-node-child', sans metadata.
-Skip the optional metadata node at pos 0 if present."
-  (let ((value-nodes (seq-filter (lambda (child)
-                                   (string= (treesit-node-field-name child) "value"))
-                                 (treesit-node-children node t))))
-    (seq-elt value-nodes n)))
+  "Return the Nth value-field child of NODE, skipping metadata children."
+  ;; Walks siblings directly via C-level tree-sitter calls to avoid
+  ;; allocating intermediate lists, as this is called frequently on hot paths.
+  (let ((child (treesit-node-child-by-field-name node "value"))
+        (remaining n))
+    (while (and child (> remaining 0))
+      (setq child (treesit-node-next-sibling child t))
+      (when (and child (equal "value" (treesit-node-field-name child)))
+        (setq remaining (1- remaining))))
+    child))
 
 (defun clojure-ts--first-value-child (node)
   "Return the first value child of the given NODE.

test/clojure-ts-mode-node-child-skip-metadata-test.el

@@ -0,0 +1,108 @@
+;;; clojure-ts-mode-node-child-skip-metadata-test.el --- Tests for node-child-skip-metadata  -*- lexical-binding: t; -*-
+
+;; Copyright © 2026 Dieter Komendera
+
+;; This file is not part of GNU Emacs.
+
+;; This program is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; This program is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; Tests for `clojure-ts--node-child-skip-metadata'.
+
+;;; Code:
+
+(require 'clojure-ts-mode)
+(require 'buttercup)
+(require 'test-helper "test/test-helper")
+
+(defun clojure-ts-test--first-list-node ()
+  "Return the first list_lit node in the current buffer."
+  (car (mapcar #'cdr (treesit-query-capture
+                      (treesit-buffer-root-node) "(list_lit) @n"))))
+
+(describe "clojure-ts--node-child-skip-metadata"
+  (it "returns the first value child of a simple list"
+    (with-clojure-ts-buffer "(defn foo [x] x)"
+      (let ((list-node (clojure-ts-test--first-list-node)))
+        (expect (treesit-node-text (clojure-ts--node-child-skip-metadata list-node 0))
+                :to-equal "defn")
+        (expect (treesit-node-text (clojure-ts--node-child-skip-metadata list-node 1))
+                :to-equal "foo"))))
+
+  (it "skips metadata on the symbol (^:private)"
+    (with-clojure-ts-buffer "(defn ^:private foo [x] x)"
+      (let ((list-node (clojure-ts-test--first-list-node)))
+        (expect (treesit-node-text (clojure-ts--node-child-skip-metadata list-node 0))
+                :to-equal "defn")
+        (expect (treesit-node-text (clojure-ts--node-child-skip-metadata list-node 1))
+                :to-equal "foo"))))
+
+  (it "skips multiple metadata annotations"
+    (with-clojure-ts-buffer "(defn ^:private ^:dynamic foo [x] x)"
+      (let ((list-node (clojure-ts-test--first-list-node)))
+        (expect (treesit-node-text (clojure-ts--node-child-skip-metadata list-node 0))
+                :to-equal "defn")
+        (expect (treesit-node-text (clojure-ts--node-child-skip-metadata list-node 1))
+                :to-equal "foo"))))
+
+  (it "skips type-hint metadata"
+    (with-clojure-ts-buffer "(defn ^String foo [x] x)"
+      (let ((list-node (clojure-ts-test--first-list-node)))
+        (expect (treesit-node-text (clojure-ts--node-child-skip-metadata list-node 0))
+                :to-equal "defn")
+        (expect (treesit-node-text (clojure-ts--node-child-skip-metadata list-node 1))
+                :to-equal "foo"))))
+
+  (it "skips map metadata on the symbol"
+    (with-clojure-ts-buffer "(defn ^{:doc \"hello\"} foo [x] x)"
+      (let ((list-node (clojure-ts-test--first-list-node)))
+        (expect (treesit-node-text (clojure-ts--node-child-skip-metadata list-node 0))
+                :to-equal "defn")
+        (expect (treesit-node-text (clojure-ts--node-child-skip-metadata list-node 1))
+                :to-equal "foo"))))
+
+  (it "works with def forms"
+    (with-clojure-ts-buffer "(def ^:private my-var 42)"
+      (let ((list-node (clojure-ts-test--first-list-node)))
+        (expect (treesit-node-text (clojure-ts--node-child-skip-metadata list-node 0))
+                :to-equal "def")
+        (expect (treesit-node-text (clojure-ts--node-child-skip-metadata list-node 1))
+                :to-equal "my-var"))))
+
+  (it "works with ns forms"
+    (with-clojure-ts-buffer "(ns ^{:doc \"my ns\"} my.namespace)"
+      (let ((list-node (clojure-ts-test--first-list-node)))
+        (expect (treesit-node-text (clojure-ts--node-child-skip-metadata list-node 0))
+                :to-equal "ns")
+        (expect (treesit-node-text (clojure-ts--node-child-skip-metadata list-node 1))
+                :to-equal "my.namespace"))))
+
+  (it "returns nil when n is out of range"
+    (with-clojure-ts-buffer "(foo)"
+      (let ((list-node (clojure-ts-test--first-list-node)))
+        (expect (clojure-ts--node-child-skip-metadata list-node 0)
+                :not :to-be nil)
+        (expect (clojure-ts--node-child-skip-metadata list-node 1)
+                :to-be nil))))
+
+  (it "works with non-symbol value children"
+    (with-clojure-ts-buffer "(def foo [1 2 3])"
+      (let ((list-node (clojure-ts-test--first-list-node)))
+        (expect (treesit-node-text (clojure-ts--node-child-skip-metadata list-node 0))
+                :to-equal "def")
+        (expect (treesit-node-text (clojure-ts--node-child-skip-metadata list-node 1))
+                :to-equal "foo")))))
+
+;;; clojure-ts-mode-node-child-skip-metadata-test.el ends here