I have this code to highlight tab characters and want to disable them using project-specifics macro:
(require 'highlight-chars)
(make-variable-buffer-local 'prevent-highlight-tabs)
(setq highlight-chars-disable '(term-mode erc-mode fundamental-mode))
(setq-default prevent-highlight-tabs nil)
(add-hook 'font-lock-mode-hook
(lambda()
(message "lock")
(when (and (null (memql major-mode highlight-chars-disable))
(not prevent-highlight-tabs))
(message "%s" prevent-highlight-tabs)
(hc-highlight-tabs))))
(custom-set-faces '(hc-tab ((t (:background "red")))))
and project-specifics is a macro that define add find-file-hook and dired-after-readin-hook from this question
(project-specifics "projects/test"
(message "specific")
(setq prevent-highlight-tabs t)
(setq indent-tabs-mode t))
What I wanted to do is disable red tabs (I want them because in most projects I want only spaces, and want to see tabs) for files in project/test, but I have a problem because the code from font-lock-mode-hook is executing before project-specifics (find-file-hook), and prevent-highlight-tabs is always nil in font-lock-mode-hook. Why is that, and how to fix it?
What you are doing seems convoluted.
And it is partly undefined (here) - e.g., what is the major mode highlight-chars-disable? That is not defined in library highlight-chars.el, and it doesn't sound like something that would be a good candidate for a major mode.
See the Commentary of library highlight-chars.el for suggestions.
Something like this, perhaps (and you would put property prevent-highlight-tabs on any major-mode symbols you like:
(add-hook 'font-lock-mode-hook
(lambda () (unless (get major-mode 'prevent-highlight-tabs)
(hc-highlight-tabs))))
Or something like this (from the Commentary):
(add-hook 'change-major-mode-hook
(lambda ()
(add-hook 'font-lock-mode-hook 'hc-highlight-tabs)))
(add-hook 'after-change-major-mode-hook
(lambda ()
(when (eq major-mode 'THE-MODE)
(remove-hook 'font-lock-mode-hook 'hc-highlight-tabs)
(hc-dont-highlight-tabs)))
'APPEND)