Re: questions about blink-cursor-mode

[Juanma Barranquero <lekktu@gmail.com>]

On Wed, Nov 18, 2009 at 19:59, Drew Adams <drew.adams@oracle.com> wrote:

> blink-cursor-mode is defined using `define-minor-mode', and the doc for that
> says that "It finishes by running the mode hook variable `MODE-hook'." But there
> doesn't seem to be any variable `blink-cursor-mode-hook'. How can that be? Why
> is that? If there were such a hook, I could presumably use it to update my
> variable that reflects the user's preference.

The code for `define-minor-mode' does this:

  (let* (...
	 (hook (intern (concat mode-name "-hook")))
	 (hook-on (intern (concat mode-name "-on-hook")))
	 (hook-off (intern (concat mode-name "-off-hook")))
         ...)

    ...

    ,@body
    ;; The on/off hooks are here for backward compatibility only.
    (run-hooks ',hook (if ,mode ',hook-on ',hook-off))

    ...

so the hook is run even if the symbol is not defvared. Some packages
declare the hook variable, some don't. (Yes, I agree it would be
better to always declare them, if only to add the standard "This is a
normal hook blah blah" docstring.)

    Juanma