Re: org-mode and mode hooks.

[Lute Kamstra]

Hi Carsten,

> I remember trying to do define-derived mode, but not doing it for a
> number of reasons which I do not exactly remember.  The argument was
> one reason.  Another was that older versions of define-derived-mode
> did not allow a BODY arguments which I needed.

> A third one was that org-mode hacks away the Show and Hide menus of
> outline mode, and I did not want a mode hood to fail because is
> tries to add entries to non-existing menus.

With my patch, running outline-mode's mode hook (and
after-change-major-mode-hook) is delayed; it is run at the end of
org-mode.  So it introduces the problem that a mode hook will fail
when it tries to change those menus.

> An important problem always is that I am writing code for Emacs and
> XEmacs, so my code needs to be compatible with both distributions.

AFAIK, XEmacs has delay-mode-hooks and run-mode-hooks as well.

> I did not know about delay-mode-hooks and run-mode-hooks - I'll check
> it out.
>
> What is actually the problem created by the current setup?  What are
> you trying to do in the outline-mode-hook, and how does it interfer
> with what org-mode is doing?

My problem is not with outline-mode-hook but with
after-change-major-mode-hook.

In Emacs, global-font-lock-mode (and any other global minor mode
defined with define-global-minor-mode) adds one function to
change-major-mode-hook and a second function to
after-change-major-mode-hook to enable Font Lock mode.  The first
functions adds the current buffer to a list variable.  The second
function enables Font Lock mode for all buffers in that list and
clears the list.

change-major-mode-hook is run by kill-all-local-variables and
after-change-major-mode-hook is run by run-mode-hooks.  So normally, a
major mode calls the first function once as the first thing it does
and the second function once as the last thing it does.  However,
org-mode calls the second function halfway, before it sets up its own
Font-Lock stuff.  As a result Font Lock doesn't work properly for
org-mode.

Lute.


PS.  Putting the second function on after-change-major-mode-hook is a
     recent change, it used to be on find-file-hook.