.dir-locals for specific directory but not its children

Question

How to set a directory local variable for a directory itself non-recursively? I don't want the variable set in .dir-locals.el affect the sub-directories.

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Edited:

My use case is: I'd like to hide dot files under ~ by setting dired-omit-files since there are quite a lot of them in my home directory. But I do not want to hide dot files of any other subdirectory of ~. Though I think I can set it using some dired-mode-hook by comparing buffer-name or buffer-file-name, I guessed there may be simpler solution by using directory local variables.

Answer 1

The Directory Variables section of the emacs manual says:

Here’s an example of a ‘.dir-locals.el’ file:

 ((nil . ((indent-tabs-mode . t)
          (fill-column . 80)
          (mode . auto-fill)))
  (c-mode . ((c-file-style . "BSD")
             (subdirs . nil)))
  ("src/imported"
   . ((nil . ((change-log-default-name
               . "ChangeLog.local"))))))

[... snip ...] The special ‘subdirs’ element is not a variable, but a special keyword which indicates that the C mode settings are only to be applied in the current directory, not in any subdirectories.

so that should do the job, e.g.

((nil . ((dired-omit-files . t)
         (subdirs . nil))))

although for some reason when I test, it seems to be applying to all directories, and don't have time to figure out why. Perhaps you'll have better luck!

Answer 2

No, there isn't. You can set the variable in the directory-local variables, and the unset it in the child directory's variables. Or you can use file-local variables.