From 928bad93609773ca5e9c94cf6e8f24e895e263d3 Mon Sep 17 00:00:00 2001
From: Yuan Fu <casouri@gmail.com>
Date: Mon, 17 Feb 2025 13:27:52 -0800
Subject: [PATCH] Rename treesit-simple-indent-modify-rules and fix docstring

* lisp/treesit.el (treesit-simple-indent-modify-rules): Rename
and fix docstring.  It should be matcher, not anchor.  Also
reword a little bit.
* etc/NEWS: Update.
* lisp/textmodes/mhtml-ts-mode.el:
(mhtml-ts-mode--treesit-indent-rules): Update accordingly.
---
 etc/NEWS                        | 11 +++++------
 lisp/textmodes/mhtml-ts-mode.el |  4 ++--
 lisp/treesit.el                 | 18 ++++++++++++------
 3 files changed, 19 insertions(+), 14 deletions(-)

diff --git a/etc/NEWS b/etc/NEWS
index 190da3e3797..95606658a1d 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -1404,12 +1404,11 @@ settings.  In a multi-language major mode it is sometimes necessary to
 replace features from one of the major modes, with others that are
 better suited to the new multilingual context.
 
-*** New function 'treesit-modify-indent-rules'.
-Given two tree-sitter indent rules, it replaces, adds, or prepends the
-new rules to the old ones, then returns the new tree-sitter indent
-rules.  In a multi-language major mode it is sometimes necessary to
-modify rules from one of the major modes, with others that are better
-suited to the new multilingual context.
+*** New function 'treesit-simple-indent-modify-rules'.
+Given two tree-sitter indent rules, it replaces, adds, or prepends rules
+in the old rules with new ones, then returns the modified rules.  In a
+multi-language major mode it is sometimes necessary to modify rules from
+one of the major modes to better suit the new multilingual context.
 
 +++
 *** New command 'treesit-explore'.
diff --git a/lisp/textmodes/mhtml-ts-mode.el b/lisp/textmodes/mhtml-ts-mode.el
index 0d53176f166..64f44751213 100644
--- a/lisp/textmodes/mhtml-ts-mode.el
+++ b/lisp/textmodes/mhtml-ts-mode.el
@@ -324,14 +324,14 @@ NODE and PARENT are ignored."
            ;; Extended rules for js and css, to
            ;; indent appropriately when injected
            ;; into html
-           (treesit-modify-indent-rules
+           (treesit-simple-indent-modify-rules
             'javascript
             `((javascript ((parent-is "program")
                            mhtml-ts-mode--js-css-tag-bol
                            mhtml-ts-mode--js-css-indent-offset)))
             js--treesit-indent-rules
             :replace)
-           (treesit-modify-indent-rules
+           (treesit-simple-indent-modify-rules
             'css
             `((css ((parent-is "stylesheet")
                     mhtml-ts-mode--js-css-tag-bol
diff --git a/lisp/treesit.el b/lisp/treesit.el
index cd95524fdf4..efc3b153ee8 100644
--- a/lisp/treesit.el
+++ b/lisp/treesit.el
@@ -2540,12 +2540,18 @@ end of existing rules."
               (append rules existing-rules)))))
     (setf (alist-get language treesit-simple-indent-rules) new-rules)))
 
-(defun treesit-modify-indent-rules (lang new-rules rules &optional how)
-  "Modify a copy of RULES using NEW-RULES.
-As default replace rules with the same anchor.
-When HOW is :prepend NEW-RULES are prepend to RULES, when
-:append NEW-RULES are appended to RULES, when :replace (the default)
-NEW-RULES replace rule in RULES which the same anchor."
+(defun treesit-simple-indent-modify-rules (lang new-rules rules &optional how)
+  "Pick out rules for LANG in RULES, and modify it according to NEW_RULES.
+
+RULES should have the same form as `treesit-simple-indent-rules', i.e, a
+list of (LANG RULES...).  Return a new modified rules in the form
+of (LANG RULES...).
+
+If HOW is omitted or :replace, for each rule in NEW-RULES, find the old
+rule that has the same matcher, and replace it.
+
+If HOW is :prepend, just prepend NEW-RULES to the old rules; if HOW is
+:append, append NEW-RULES."
   (cond
    ((not (alist-get lang rules))
     (error "No rules for language %s in RULES" lang))