master c65c5d02224 01/11: Improve c-ts-mode compound indents (bug#74507)

[Yuan Fu]

branch: master
commit c65c5d02224335562be7e04dd1bf185dfca3dbf1
Author: Jørgen Kvalsvik <j@lambda.is>
Commit: Yuan Fu <casouri@gmail.com>

    Improve c-ts-mode compound indents (bug#74507)
    
    Properly indent the body of compound expressions, even when then
    compound expression is not at the beginning of line and the
    parent is not an if/for/while/etc., and matches the behavior of
    c-mode.
    
    This fixes a problem that is common with macros and in testing
    frameworks. For example, you expect this to indent:
    
    TEST_CASE(1) {
        assert (...);
    }
    
    If the compound statement is the function body itself, don't
    apply this new rule and instead guide by the parent and first
    sibling.
    
    I'm sure there are subtle interactions that aren't handled
    properly by checking for "function_definition" rather than
    something more general, but it does fix the test case and the
    check can be improved as more cases are found.
    
    * lisp/progmodes/c-ts-mode.el:
    (c-ts-mode--parent-is-not-top-compound): New function.
    (c-ts-mode--indent-styles): Use it.
    * test/lisp/progmodes/c-ts-mode-resources/indent.erts: New
    compound statement test.
---
 lisp/progmodes/c-ts-mode.el                        |  9 +++++++
 .../lisp/progmodes/c-ts-mode-resources/indent.erts | 30 ++++++++++++++++++++++
 2 files changed, 39 insertions(+)

diff --git a/lisp/progmodes/c-ts-mode.el b/lisp/progmodes/c-ts-mode.el
index cbb103cfaf7..59b34ef6b8b 100644
--- a/lisp/progmodes/c-ts-mode.el
+++ b/lisp/progmodes/c-ts-mode.el
@@ -403,6 +403,12 @@ PARENT is its parent."
               (treesit-node-start parent)
               (line-end-position))))))
 
+(defun c-ts-mode--parent-is-not-top-compound (_n parent &rest _)
+  "Matches when PARENT is not the top level compound statement.
+The top-level compound is the {} that immediately follows the function
+signature."
+  (not (equal "function_definition" (treesit-node-type (treesit-node-parent 
parent)))))
+
 (defun c-ts-mode--indent-styles (mode)
   "Indent rules supported by `c-ts-mode'.
 MODE is either `c' or `cpp'."
@@ -479,6 +485,7 @@ MODE is either `c' or `cpp'."
            ;; Closing bracket.  This should be before initializer_list
            ;; (and probably others) rule because that rule (and other
            ;; similar rules) will match the closing bracket.  (Bug#61398)
+           ((and (node-is "}") c-ts-mode--parent-is-not-top-compound) 
parent-bol 0)
            ((node-is "}") standalone-parent 0)
            ,@(when (eq mode 'cpp)
                '(((node-is "access_specifier") parent-bol 0)
@@ -498,6 +505,8 @@ MODE is either `c' or `cpp'."
            ((parent-is "field_declaration_list") 
c-ts-mode--anchor-prev-sibling 0)
 
            ;; Statement in {} blocks.
+           ((and (parent-is "compound_statement") 
c-ts-mode--parent-is-not-top-compound)
+            parent-bol c-ts-mode-indent-offset)
            ((or (and (parent-is "compound_statement")
                      ;; If the previous sibling(s) are not on their
                      ;; own line, indent as if this node is the first
diff --git a/test/lisp/progmodes/c-ts-mode-resources/indent.erts 
b/test/lisp/progmodes/c-ts-mode-resources/indent.erts
index 2f3540c3970..61e61677ed7 100644
--- a/test/lisp/progmodes/c-ts-mode-resources/indent.erts
+++ b/test/lisp/progmodes/c-ts-mode-resources/indent.erts
@@ -223,6 +223,36 @@ make_pair(int long_identifier_a[], int long_identifier_b[],
 
 =-=-=
 
+Name: Compound Statement after code
+
+=-=
+#define IOTA(var, n) for (int var = 0; var != (n); ++var)
+int main()
+{
+IOTA (v, 10) {
+printf("%d ", v);
+}
+
+const char *msg = "Hello, world!"; {
+puts("Hello, world!");
+}
+}
+
+=-=
+#define IOTA(var, n) for (int var = 0; var != (n); ++var)
+int main()
+{
+  IOTA (v, 10) {
+    printf("%d ", v);
+  }
+
+  const char *msg = "Hello, world!"; {
+    puts("Hello, world!");
+  }
+}
+
+=-=-=
+
 Name: Switch-Case statement
 
 =-=