What does ad-activate do?
advising-functions, defadvice, elisp, emacs
Solution
While asking this question, I realized that I just didn't get the idea of advising functions.
It became clear to me that:
- `align-regexp-with-spaces` isn't a function nor a variable but only a name (to enable/disable single pieces of advice)
- ever since `(ad-activate 'align-regexp)`, `align-regexp` just does what I 'advised' it to: not to use tabs
So: `ad-activate` activates the advice, effectively changing the original function's behavior. Great!
I don't get why this is 'better' than defining a function around `align-regexp` though. But then again I don't know much about Emacs Lisp.
I'm afraid the extra lines of documentation only added to the confusion...
Problem
In an answer, I noticed: ``` ;; Align with spaces only (defadvice align-regexp (around align-regexp-with-spaces) "Never use tabs for alignment." (let ((indent-tabs-mode nil)) ad-do-it)) (ad-activate 'align-regexp) ``` This sounds promising, but... what does it do?! I tried `eval-region` on the block of code. But for me, all it does is adding the following to the `align-regexp` docs: This function is advised. Around-advice `align-regexp-with-spaces': Never use tabs for alignment. I don't seem to be able to actually use `align-regexp-with-spaces`, if that's what should be the effect... What am I missing? I used GNU Emacs version 24.0.96.1 (i386-mingw-nt6.1.7601).