If I create a bad
[[file:link]] or an internal
[[Link]] that does not exist, I would like to
org-mode to fontify this using
org-warning face. How can I get this done?
In org-9 it might be as simple as this for file links:
(org-link-set-parameters "file" :face (lambda (path) (if (file-exists-p path) 'org-link 'org-warning)))
For internal links I don't know an easy way to do it.