Emacs and Indentation

Posted on May 11, 2019 | emacs

Though I have been using emacs for few years now, I faced issues with controlling the indentation. Consider the below setting in vim to configure the indentation for all source files in a directory.

  • Use tabs for indentation
  • Treat tab width as 8 spaces
au BufEnter /code/kernel/*/*.[ch] setlocal tabstop=8 shiftwidth=8 noexpandtab

I tried dtrt-indent which automatically configures indentation based on existing indentation in the file. This approach works well for existing source files but does not configure indentation for new source files.

I settled on replicating the vim behaviour exactly by using per directory local variables.

(dir-locals-set-class-variables
 'kernel-src-directory
 '(
   (c-mode . (
	      (c-basic-offset . 8)
	      (evil-shift-width . 8)
	      (indent-tabs-mode . t)
	      )
	   )
   )
 )
(dir-locals-set-directory-class
    "/code/kernel" 'kernel-src-directory)

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