>> In `.dir-locals.el' setting `((asm-mode . ((asm-comment-char . 35))))'
>> does not have the desired effect.  The comment char is still `;' instead
>> of `#'.  The reason is that when the syntax table is adjusted according
>> to the comment char in the body of `asm-mode', the dir-local variables
>> haven't been loaded yet: `run-mode-hooks' (which would call
>> `hack-local-variables') is only invoked _after_ the `define-derived-mode'
>> body, i.e., too late.
>> 
>> I'm using the following workaround:
>> 
>>     (defun asm-mode-set-comment-char-from-dir-local-variables ()
>>       "Load `asm-comment-char' from dir-local variables.
>>     This is a HACK, since in `asm-mode', `run-mode-hooks' (which would call
>>     `hack-local-variables') is only invoked after the `define-derived-mode' body,
>>     i.e., too late."
>>       (let ((enable-local-variables :safe))
>>         (hack-dir-local-variables)
>>         (when-let* ((char (alist-get 'asm-comment-char dir-local-variables-alist)))
>>           (setq-local asm-comment-char char))))
>>     (add-hook 'asm-mode-set-comment-hook #'asm-mode-set-comment-char-from-dir-local-variables)
>> 
>> But maybe there is a more principled approach?
>
> Stefan, any suggestions?

IIRC there are 2 "standard" solutions:

- in `asm-mode` use

      (add-hook 'hack-local-variables-hook #'asm--set-comment-syntax nil t)

  where `asm--set-comment-syntax` would be a new function that sets the
  syntax-table according to `asm-comment-char`.

- in `asm-mode` move the syntax-table setting code to an `:after-hook`
  section, as in the patch below.


        Stefan