Improve performance of clojure-ts-align

Cache semantic indentation rules for a single clojure-ts-align run to avoid
lookup for every repeating symbol.

Author: rrudakov

CHANGELOG.md

@@ -11,6 +11,7 @@
 - Fix font-lock issues: duplicate query, missing `definline` metadata docstring.
 - Fix missing builtin symbols in font-lock regexp.
 - Improve performance for imenu, font-lock and indentation.
+- Improve performance for `clojure-ts-align` by caching indentation rules.
 
 ## 0.6.0 (2025-12-02)
 

clojure-ts-mode.el

@@ -1442,17 +1442,34 @@ If NS is defined, then the fully qualified symbol is passed to
                        (seq-sort (lambda (spec1 _spec2)
                                    (equal (car spec1) :block)))))))))
 
-(defun clojure-ts--find-semantic-rules-for-node (node)
-  "Return a list of semantic rules for NODE."
-  (let* ((first-child (clojure-ts--node-child-skip-metadata node 0))
-         (symbol-name (clojure-ts--named-node-text first-child))
-         (symbol-namespace (clojure-ts--node-namespace-text first-child)))
+(defvar clojure-ts--dynamic-indent-for-symbol-cache
+  (make-hash-table :test 'equal))
+
+(defvar clojure-ts--dynamic-indent-for-symbol-cache-p nil
+  "If set to nil, do not use cache for dynamic indentation rules.")
+
+(defun clojure-ts--find-semantic-rules-for-symbol (node)
+  "Return a list of semantic rules for symbol NODE.
+
+If rules are not found return :not-found symbol."
+  (let ((symbol-name (clojure-ts--named-node-text node))
+        (symbol-namespace (clojure-ts--node-namespace-text node)))
     (or (clojure-ts--dynamic-indent-for-symbol symbol-name symbol-namespace)
         (alist-get symbol-name
                    clojure-ts--semantic-indent-rules-cache
                    nil
                    nil
-                   #'equal))))
+                   #'equal)
+        :not-found)))
+
+(defun clojure-ts--find-semantic-rules-for-node (node)
+  "Return a list of semantic rules for NODE."
+  (let* ((first-child (clojure-ts--first-value-child node))
+         (symbol-full-name (treesit-node-text first-child)))
+    (if clojure-ts--dynamic-indent-for-symbol-cache-p
+        (with-memoization (gethash symbol-full-name clojure-ts--dynamic-indent-for-symbol-cache)
+          (clojure-ts--find-semantic-rules-for-symbol first-child))
+      (clojure-ts--find-semantic-rules-for-symbol first-child))))
 
 (defun clojure-ts--find-semantic-rule (node parent current-depth)
   "Return a suitable indentation rule for NODE, considering the CURRENT-DEPTH.
@@ -1464,7 +1481,8 @@ increasing the CURRENT-DEPTH.  If a rule is not found upon reaching the
 root of the syntax tree, it returns nil.  A rule is considered a match
 only if the CURRENT-DEPTH matches the rule's required depth."
   (let* ((idx (- (treesit-node-index node) 2)))
-    (if-let* ((rule-set (clojure-ts--find-semantic-rules-for-node parent)))
+    (if-let* ((rule-set (clojure-ts--find-semantic-rules-for-node parent))
+              ((not (equal rule-set :not-found))))
         (if (zerop current-depth)
             (let ((rule (car rule-set)))
               (if (equal (car rule) :block)
@@ -1899,6 +1917,7 @@ subsequent special arguments based on block indentation rules."
     ;; indentation rules.  First node to skip is the symbol itself.
     (when (equal sexp-type 'cond)
       (if-let* ((rule-set (clojure-ts--find-semantic-rules-for-node node))
+                ((not (equal rule-set :not-found)))
                 (rule (car rule-set))
                 ((equal (car rule) :block)))
           (treesit-beginning-of-thing 'sexp (1- (- (cadr rule))) 'restrict)
@@ -1919,9 +1938,11 @@ between BEG and END."
                            (end (clojure-ts--end-of-defun-pos)))
                        (list start end))))))
   (setq end (copy-marker end))
+  (clrhash clojure-ts--dynamic-indent-for-symbol-cache)
   (let* ((sexps-to-align (clojure-ts--get-nodes-to-align beg (marker-position end)))
          ;; We have to disable it here to avoid endless recursion.
-         (clojure-ts-align-forms-automatically nil))
+         (clojure-ts-align-forms-automatically nil)
+         (clojure-ts--dynamic-indent-for-symbol-cache-p t))
     (save-excursion
       (indent-region beg (marker-position end))
       (dolist (sexp sexps-to-align)

test/clojure-ts-mode-indentation-test.el

@@ -759,7 +759,24 @@ b |20])"
   (it "should remove extra commas"
     (with-clojure-ts-buffer-point "{|:a 2, ,:c 4}"
       (call-interactively #'clojure-ts-align)
-      (expect (buffer-string) :to-equal "{:a 2, :c 4}"))))
+      (expect (buffer-string) :to-equal "{:a 2, :c 4}")))
+
+  (it "should not fail to align a cond form without a semantic indentation rule"
+    ;; A symbol added to `clojure-ts-align-cond-forms' need not have a matching
+    ;; semantic indentation rule.  When it has none, alignment must fall back
+    ;; gracefully instead of raising `(wrong-type-argument listp :not-found)'.
+    (with-clojure-ts-buffer-point "
+(my-cond
+ |:a 1
+ :bbbb 2
+ :cc 3)"
+      (setq-local clojure-ts-align-cond-forms (cons "my-cond" clojure-ts-align-cond-forms))
+      (call-interactively #'clojure-ts-align)
+      (expect (buffer-string) :to-equal "
+(my-cond
+ :a 1
+ :bbbb 2
+ :cc 3)"))))
 
 (describe "clojure-ts-align-forms-automatically"
   ;; Copied from `clojure-mode'