Add treesit-add-simple-indent-rules

* lisp/treesit.el:
(treesit-add-simple-indent-rules): New function.
* etc/NEWS: Update NEWS.
*
test/src/treesit-tests.el:
(treesit-test-add-simple-indent-rules): Add a test for the new
function.

1 files changed, 21 insertions, 0 deletions

diff --git a/test/src/treesit-tests.el b/test/src/treesit-tests.el
index f9c64f792d1..22f53243274 100644
--- a/test/src/treesit-tests.el
+++ b/test/src/treesit-tests.el
@@ -411,6 +411,27 @@ BODY is the test body."
    (let ((missing-bracket (treesit-node-child array -1)))
      (treesit-search-forward missing-bracket "" t))))
 
+;;; Indent
+
+(ert-deftest treesit-test-add-simple-indent-rules ()
+  "Test `treesit-add-simple-indent-rules'."
+  (let ((treesit-simple-indent-rules
+         (copy-tree '((c (a a a) (b b b) (c c c))))))
+    (treesit-add-simple-indent-rules 'c '((d d d)))
+    (should (equal treesit-simple-indent-rules
+                   '((c (d d d) (a a a) (b b b) (c c c)))))
+    (treesit-add-simple-indent-rules 'c '((e e e)) :after)
+    (should (equal treesit-simple-indent-rules
+                   '((c (d d d) (a a a) (b b b) (c c c) (e e e)))))
+    (treesit-add-simple-indent-rules 'c '((f f f)) :after '(b b b))
+    (should (equal treesit-simple-indent-rules
+                   '((c (d d d) (a a a) (b b b) (f f f)
+                        (c c c) (e e e)))))
+    (treesit-add-simple-indent-rules 'c '((g g g)) :before '(b b b))
+    (should (equal treesit-simple-indent-rules
+                   '((c (d d d) (a a a) (g g g)
+                        (b b b) (f f f) (c c c) (e e e)))))))
+
 ;;; Query
 
 (defun treesit--ert-pred-last-sibling (node)