lang/cc: rewrite & polish style settings

Doom used to have its own cc-mode style, which was difficult to
customize without first undoing all its changes.

A doom entry has been added to c-style-alist, which represents
a marriage of various styles (mostly linux), plus some context-sensitive
indentation functions which I think are reasonable.

More importantly, it can be disabled by changing c-default-style.

Also, removed a few hacks that have been merged into v5.33+ of cc-mode.
25.1 users beware! You may not have these changes.

modules/lang/cc/autoload.el

@@ -19,19 +19,6 @@
   (when (and (featurep 'irony) irony-mode)
     (+cc|irony-init-compile-options)))
 
-;;;###autoload
-(defun +cc*align-lambda-arglist (orig-fun &rest args)
-  "Improve indentation of continued C++11 lambda function opened as argument."
-  (if (and (eq major-mode 'c++-mode)
-           (ignore-errors
-             (save-excursion
-               (goto-char (c-langelem-pos langelem))
-               ;; Detect "[...](" or "[...]{". preceded by "," or "(",
-               ;;   and with unclosed brace.
-               (looking-at-p ".*[(,][ \t]*\\[[^]]*\\][ \t]*[({][^}]*$"))))
-      0 ; no additional indent
-    (apply orig-fun args)))
-
 ;;;###autoload
 (defun +cc-sp-point-is-template-p (id action context)
   "Return t if point is in the right place for C++ angle-brackets."
@@ -50,17 +37,26 @@
          (looking-at-p "[ 	]*#include[^<]+"))))
 
 ;;;###autoload
-(defun +cc-c-lineup-inclass (_langelem)
-  "Indent privacy keywords at same level as class properties."
-  (if (memq major-mode '(c-mode c++-mode))
-      (let ((inclass (assq 'inclass c-syntactic-context)))
-        (save-excursion
-          (goto-char (c-langelem-pos inclass))
-          (if (or (looking-at "struct")
-                  (looking-at "typedef struct"))
-              '+
-            '++)))
-    '+))
+(defun +cc-c++-lineup-inclass (langelem)
+  "Indent inclass lines one level further than access modifier keywords."
+  (when (and (eq major-mode 'c++-mode)
+             (or (assoc 'access-label c-syntactic-context)
+                 (save-excursion
+                   (save-match-data
+                     (re-search-backward
+                      "\\(?:p\\(?:ublic\\|r\\(?:otected\\|ivate\\)\\)\\)"
+                      (c-langelem-pos langelem) t)))))
+    '++))
+
+;;;###autoload
+(defun +cc-lineup-arglist-close (langlem)
+  "Line up the closing brace in an arglist with the opening brace IF cursor is
+preceded by the opening brace or a comma (disregarding whitespace in between)."
+  (when (save-excursion
+          (save-match-data
+            (skip-chars-backward " \t\n" (c-langelem-pos langelem))
+            (memq (char-before) (list ?, ?\( ?\;))))
+    (c-lineup-arglist langlem)))
 
 
 ;;

modules/lang/cc/config.el

@@ -48,7 +48,8 @@ compilation database is present in the project.")
 
   :init
   (setq-default c-basic-offset tab-width
-                c-backspace-function #'delete-backward-char)
+                c-backspace-function #'delete-backward-char
+                c-default-style "doom")
 
   :config
   (set! :electric '(c-mode c++-mode objc-mode java-mode)
@@ -61,24 +62,41 @@ compilation database is present in the project.")
   ;; C/C++ style settings
   (c-toggle-electric-state -1)
   (c-toggle-auto-newline -1)
-  (c-set-offset 'substatement-open '0) ; don't indent brackets
-  (c-set-offset 'inline-open       '+)
-  (c-set-offset 'block-open        '+)
-  (c-set-offset 'brace-list-open   '+)
-  (c-set-offset 'case-label        '+)
-  (c-set-offset 'access-label      '-)
-  (c-set-offset 'arglist-intro     '+)
-  (c-set-offset 'arglist-close     '0)
-  ;; Indent privacy keywords at same level as class properties
-  ;; (c-set-offset 'inclass #'+cc-c-lineup-inclass)
 
   ;;; Better fontification (also see `modern-cpp-font-lock')
   (add-hook 'c-mode-common-hook #'rainbow-delimiters-mode)
   (add-hook! (c-mode c++-mode) #'highlight-numbers-mode)
   (add-hook! (c-mode c++-mode) #'+cc|fontify-constants)
 
-  ;; Improve indentation of inline lambdas in C++11
-  (advice-add #'c-lineup-arglist :around #'+cc*align-lambda-arglist)
+  ;; Custom style, based off of linux
+  (map-put c-style-alist "doom"
+           `((c-basic-offset . ,tab-width)
+             (c-comment-only-line-offset . 0)
+             (c-hanging-braces-alist (brace-list-open)
+                                     (brace-entry-open)
+                                     (substatement-open after)
+                                     (block-close . c-snug-do-while)
+                                     (arglist-cont-nonempty))
+             (c-cleanup-list brace-else-brace)
+             (c-offsets-alist
+              (statement-block-intro . +)
+              (knr-argdecl-intro . 0)
+              (substatement-open . 0)
+              (substatement-label . 0)
+              (statement-cont . +)
+              (case-label . +)
+              ;; align args with open brace OR don't indent at all (if open brace
+              ;; is at eolp and close brace is after arg with no trailing comma)
+              (arglist-intro . +)
+              (arglist-close +cc-lineup-arglist-close 0)
+              ;; don't over-indent lambda blocks
+              (inline-open . 0)
+              (inlambda . 0)
+              ;; indent access keywords +1 level, and properties beneath them
+              ;; another level
+              (access-label . -)
+              (inclass +cc-c++-lineup-inclass +)
+              (label . 0))))
 
   ;;; Keybindings
   ;; Completely disable electric keys because it interferes with smartparens and