Why doesn’t highlight-regexp highlight my regexp?

Question

When I evaluate (highlight-regexp "todo" "hi-blue") in a buffer, “todo” gets highlighted in that buffer. I’d like “todo” to be highlighted in any buffer, always.

I’ve tried putting the following code in my Aquamacs Preferences.el file (equivalent to Emacs’ .emacs), based on what I read here:

(global-hi-lock-mode 1)
(setq hi-lock-file-patterns-policy (lambda (dummy) t))
(highlight-regexp "todo" "hi-blue")

But “todo” doesn’t get highlighted. What am I missing?

Answer 1

I am not sure why the hihglight-regexp does not work, but to get TODO highlighted in any buffer I recommend using the hl-todo package.

You do not have to 'sharp quote' a lambda expression as it is self-quoting (see 'lambda' docstring).

Answer 2

highlight-regexp does its thing in the current buffer which likely is not set when Preferences.el is read. To achieve the desired effect in every buffer, you need to call it in some hook that is fired when buffers are created but I do not know a good candidate.