From 843426065091c0ee03d066ceb8432ab13ca1fa3e Mon Sep 17 00:00:00 2001
From: Yuan Fu <casouri@gmail.com>
Date: Tue, 8 Jul 2025 23:14:20 -0700
Subject: [PATCH] Add a synchronous way to get parser change ranges (bug#78402)

This commit only adds the new function, the fix for the bug is
in the next commit.

* doc/lispref/parsing.texi (Using Parser): Add docs.
* lisp/treesit.el (treesit): Add shortdoc.
* src/treesit.c (treesit_get_affected_ranges): New function
extracted from treesit_call_after_change_functions.
(treesit_call_after_change_functions): Extract out.
(treesit_ensure_parsed): Return affected regions.
(Ftreesit_parser_changed_regions): New function that returns the
affected regions.

(cherry picked from commit 564b947745b2a685edcd93eb8f0d8825352030b8)
---
 doc/lispref/parsing.texi | 11 +++++++++++
 lisp/treesit.el          | 13 +++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/doc/lispref/parsing.texi b/doc/lispref/parsing.texi
index 922ba217920..91dc5d35e54 100644
--- a/doc/lispref/parsing.texi
+++ b/doc/lispref/parsing.texi
@@ -573,6 +573,17 @@ symbol, rather than a lambda function.
 This function returns the list of @var{parser}'s notifier functions.
 @end defun
 
+A lisp program can also choose to force a parser to reparse and get the
+changed regions immediately with @code{treesit-parser-changed-regions}.
+
+@defun treesit-parser-changed-regions parser
+This function force @var{parser} to reparse, and return the affected
+regions: a list of @w{@code{(@var{start} . @var{end})}}.  If the parser
+has nothing new to reparse, or the affected regions are empty,
+@code{nil} is returned.
+@end defun
+
+
 @heading Substitute parser for another language
 @cindex remap language grammar, tree-sitter
 @cindex replace language grammar, tree-sitter
diff --git a/lisp/treesit.el b/lisp/treesit.el
index dfe7efe7d4f..a137160b382 100644
--- a/lisp/treesit.el
+++ b/lisp/treesit.el
@@ -5430,6 +5430,19 @@ Tree-sitter grammar for `%s' is missing; install it?"
   (treesit-parser-language
    :no-eval (treesit-parser-language parser)
    :eg-result c)
+  (treesit-parser-tag
+   :no-eval (treesit-parser-tag parser)
+   :eg-result 'embeded)
+  (treesit-parser-changed-regions
+   :no-eval (treesit-parser-changed-regions parser)
+   :eg-result '((1 . 10) (24 . 58)))
+
+  (treesit-parser-embed-level
+   :no-eval (treesit-parser-embed-level parser)
+   :eg-result 1)
+  (treesit-parser-set-embed-level
+   :no-eval (treesit-parser-set-embed-level parser 1))
+
   (treesit-parser-add-notifier)
   (treesit-parser-remove-notifier)
   (treesit-parser-notifiers
-- 
2.39.5