From e5751a93e5fb0dda887a8d8a8ce4691484544acf Mon Sep 17 00:00:00 2001
From: Mark Wooding <mdw@distorted.org.uk>
Date: Tue, 19 May 2020 11:48:30 +0100
Subject: [PATCH] el/dot-emacs.el: Improve `mdw-define-c-style' to support
 simple inheritance.

Delete the duplicate settings in `mdw-trustonic-c'.
---
 el/dot-emacs.el | 56 ++++++++++++++++++++++++++++++++------------------------
 1 file changed, 32 insertions(+), 24 deletions(-)

diff --git a/el/dot-emacs.el b/el/dot-emacs.el
index 9803cf0..5968944 100644
--- a/el/dot-emacs.el
+++ b/el/dot-emacs.el
@@ -1974,24 +1974,48 @@ indentation anyway."
 (defvar mdw-define-c-styles-hook nil
   "Hook run when `cc-mode' starts up to define styles.")
 
-(defmacro mdw-define-c-style (name &rest assocs)
-  "Define a C style, called NAME (a symbol), setting ASSOCs.
+(defun mdw-merge-style-alists (first second)
+  (let ((output nil))
+    (dolist (item first)
+      (let ((key (car item)) (value (cdr item)))
+	(if (string-suffix-p "-alist" (symbol-name key))
+	    (push (cons key
+			(mdw-merge-style-alists value
+						(cdr (assoc key second))))
+		  output)
+	  (push item output))))
+    (dolist (item second)
+      (unless (assoc (car item) first)
+	(push item output)))
+    (nreverse output)))
+
+(cl-defmacro mdw-define-c-style (name (&optional parent) &rest assocs)
+  "Define a C style, called NAME (a symbol) based on PARENT, setting ASSOCs.
 A function, named `mdw-define-c-style/NAME', is defined to actually install
 the style using `c-add-style', and added to the hook
 `mdw-define-c-styles-hook'.  If CC Mode is already loaded, then the style is
 set."
   (declare (indent defun))
   (let* ((name-string (symbol-name name))
+	 (var (intern (concat "mdw-c-style/" name-string)))
 	 (func (intern (concat "mdw-define-c-style/" name-string))))
     `(progn
-       (defun ,func () (c-add-style ,name-string ',assocs))
+       (setq ,var
+	     ',(if (null parent)
+		   assocs
+		 (let ((parent-list (symbol-value
+				     (intern (concat "mdw-c-style/"
+						     (symbol-name parent))))))
+		   (mdw-merge-style-alists assocs parent-list))))
+       (defun ,func () (c-add-style ,name-string ,var))
        (and (featurep 'cc-mode) (,func))
-       (add-hook 'mdw-define-c-styles-hook ',func))))
+       (add-hook 'mdw-define-c-styles-hook ',func)
+       ',name)))
 
 (eval-after-load "cc-mode"
   '(run-hooks 'mdw-define-c-styles-hook))
 
-(mdw-define-c-style mdw-c
+(mdw-define-c-style mdw-c ()
   (c-basic-offset . 2)
   (comment-column . 40)
   (c-class-key . "class")
@@ -2012,31 +2036,15 @@ set."
 		   (statement-cont . +)
 		   (statement-case-intro . +)))
 
-(mdw-define-c-style mdw-trustonic-c
+(mdw-define-c-style mdw-trustonic-c (mdw-c)
   (c-basic-offset . 4)
   (comment-column . 0)
   (c-indent-comment-alist (anchored-comment . (column . 0))
 			  (end-block . (space . 1))
 			  (cpp-end-block . (space . 1))
 			  (other . (space . 1)))
-  (c-class-key . "class")
-  (c-backslash-column . 0)
-  (c-auto-align-backslashes . nil)
-  (c-label-minimum-indentation . 0)
-  (c-offsets-alist (substatement-open . (add 0 c-indent-one-line-block))
-		   (defun-open . (add 0 c-indent-one-line-block))
-		   (arglist-cont-nonempty . mdw-c-indent-arglist-nested)
-		   (topmost-intro . mdw-c-indent-extern-mumble)
-		   (cpp-define-intro . 0)
-		   (knr-argdecl . 0)
-		   (inextern-lang . [0])
-		   (label . 0)
-		   (case-label . +)
-		   (access-label . -2)
-		   (inclass . +)
-		   (inline-open . ++)
-		   (statement-cont . +)
-		   (statement-case-intro . +)))
+  (c-offsets-alist (arglist-cont-nonempty . mdw-c-indent-arglist-nested)
+		   (access-label . -2)))
 
 (defun mdw-set-default-c-style (modes style)
   "Update the default CC Mode style for MODES to be STYLE.
-- 
2.11.0