Tweak BSD style indentation (bug#60984)

* lisp/progmodes/c-ts-mode.el (c-ts-mode--indent-styles): Simplify
rules.
* test/lisp/progmodes/c-ts-mode-resources/indent-bsd.erts: New
testfile with bsd style indentation examples.
* test/lisp/progmodes/c-ts-mode-tests.el
(c-ts-mode-test-indentation-bsd): Add a test for the new style.

lisp/progmodes/c-ts-mode.el

@@ -237,6 +237,10 @@ MODE is either `c' or `cpp'."
        ((node-is "labeled_statement") point-min 0)
        ,@common)
       (bsd
+       ((node-is "}") parent-bol 0)
+       ((node-is "labeled_statement") parent-bol c-ts-mode-indent-offset)
+       ((parent-is "labeled_statement") parent-bol c-ts-mode-indent-offset)
+       ((parent-is "compound_statement") parent-bol c-ts-mode-indent-offset)
        ((parent-is "if_statement") parent-bol 0)
        ((parent-is "for_statement") parent-bol 0)
        ((parent-is "while_statement") parent-bol 0)

test/lisp/progmodes/c-ts-mode-resources/indent-bsd.erts

@@ -0,0 +1,93 @@
+Code:
+  (lambda ()
+    (setq indent-tabs-mode nil)
+    (setq c-ts-mode-indent-offset 2)
+    (setq c-ts-mode-indent-style 'bsd)
+    (c-ts-mode)
+    (indent-region (point-min) (point-max)))
+
+Point-Char: |
+
+Name: Basic
+
+=-=
+int
+main (void)
+{
+  return 0;
+}
+=-=-=
+
+Name: Hanging Braces
+
+=-=
+int
+main (void)
+{
+  if (true)
+  {
+    |
+  }
+}
+=-=-=
+
+Name: Labels
+
+=-=
+int
+main (void)
+{
+  label:
+    return 0;
+  if (true)
+  {
+    label:
+      return 0;
+  }
+  else
+  {
+    if (true)
+    {
+      label:
+        return 0;
+    }
+  }
+}
+=-=-=
+
+Name: If-Else
+
+=-=
+int main()
+{
+  if (true)
+  {
+    return 0;
+  }
+  else
+  {
+    return 1;
+  }
+}
+=-=-=
+
+Name: Empty Line
+=-=
+int main()
+{
+  |
+}
+=-=-=
+
+Name: Consecutive blocks (bug#60873)
+
+=-=
+int
+main (int   argc,
+      char *argv[])
+{
+  {
+    int i = 0;
+  }
+}
+=-=-=

test/lisp/progmodes/c-ts-mode-tests.el

@@ -27,6 +27,10 @@
   (skip-unless (treesit-ready-p 'c))
   (ert-test-erts-file (ert-resource-file "indent.erts")))
 
+(ert-deftest c-ts-mode-test-indentation-bsd ()
+  (skip-unless (treesit-ready-p 'c))
+  (ert-test-erts-file (ert-resource-file "indent-bsd.erts")))
+
 (ert-deftest c-ts-mode-test-filling ()
   (skip-unless (treesit-ready-p 'c))
   (ert-test-erts-file (ert-resource-file "filling.erts")))