Re: the ...-unload-hook convention doesn't work

[Dave Love]

Richard Stallman <rms@gnu.org> writes:

>     I can't check the history now, but if it's been changed it hasn't been
>     done properly.  All the examples in Emacs are simple defuns.
>
> It would not be consistent to call a symbol whose names is ...-hook
> as a function.

Yes, as I said, but I believe you approved it.  There are (or were)
many such inconsistencies.

> So I think we should fix those files to use the
> feature properly.
>
> The feature is used properly in eshell.

I disagree.  For some reason, the tree I used find in is missing
lisp/eshell, but in a 21.3 tree, at least, the feature clearly isn't
being used properly in eshell for other reasons.

The -unload-hook variables shouldn't be customized; they shouldn't be
nil if they're relevant; at least some are incorrectly named (and
documented to relate to features that don't exist).  While unloading
will work for the most part, it's because of unload-feature's
heuristics, not because the hook functions are effective.
E.g. unloading `em-ls' will not execute a hook to revert the fset
`insert-directory'.  (And incidentally, the `fset' for that should
surely be `defalias'.)