Re: [PATCH] Makefile: Convert -Wimplicit-fallthrough=3 to just -Wimplicit-fallthrough for clang

[Joe Perches]

(adding Vivien Didelot for vim)

On Wed, 2019-08-14 at 19:44 -0700, Joe Perches wrote:
> On Tue, 2019-08-13 at 14:44 +0200, Miguel Ojeda wrote:
> > Hm... I would go for either __fallthrough as the rest of attributes,
> > or simply fallthrough -- FALLTHROUGH seems wrong. If you want it that
> > way for visibility, then I would choose __fallthrough, since the
> > underscores are quite prominent and anyway IDEs typically highlight
> > macros in a different color than keywords (return etc.).
> 
> Just fyi:
> 
> I added this line to my .emacs and "fallthrough" is now
> syntax highlighted like every other keyword.
> 
>   (font-lock-add-keywords 'c-mode
> 			'(("\\<\\(fallthrough\\)\\>" . font-lock-keyword-face)))
> 
> So now my linux-c-mode block is:
> 
> (defun linux-c-mode ()
>   "C mode with adjusted defaults for use with the Linux kernel."
>   (interactive)
>   (font-lock-add-keywords 'c-mode
> 			'(("\\<\\(fallthrough\\)\\>" . font-lock-keyword-face)))
>   (c-mode)
>   (c-set-style "K&R")
>   (setq c-basic-offset 8)
>   (setq c-indent-level 8)
>   (setq c-brace-imaginary-offset 0)
>   (setq c-brace-offset -8)
>   (setq c-argdecl-indent 8)
>   (setq c-label-offset -8)
>   (setq c-continued-statement-offset 8)
>   (setq indent-tabs-mode t)
>   (setq tab-width 8)
>   (setq show-trailing-whitespace t)
>   )
> 
> I don't know to do that for vim nor any other ide,
> but I trust someone will know and show how it's done.

I investigated vim a bit as I am not a vim user.

If this is the most commonly used vim style,
perhaps a reference to this style could be added
to Documentation/process/coding-style.rst

https://github.com/vivien/vim-linux-coding-style

I had thought that
	syn keyword cKeyword fallthrough
would work, but it does not add syntax coloring
	syn keyword cStatement fallthrough
does through.

If ~.vim/plugin/linuxsty.vim is commonly used, maybe
---
 plugin/linuxsty.vim | 1 +
 1 file changed, 1 insertion(+)

diff --git a/plugin/linuxsty.vim b/plugin/linuxsty.vim
index 18b2867..44824b8 100644
--- a/plugin/linuxsty.vim
+++ b/plugin/linuxsty.vim
@@ -69,6 +69,7 @@ function s:LinuxFormatting()
 endfunction
 
 function s:LinuxKeywords()
+    syn keyword cStatement fallthrough
     syn keyword cOperator likely unlikely
     syn keyword cType u8 u16 u32 u64 s8 s16 s32 s64
     syn keyword cType __u8 __u16 __u32 __u64 __s8 __s16 __s32 __s64