[luatex] multiple callbacks

[Jonathan Fine]

Karl Berry wrote:
> Excuse me for coming in late, and with such an obvious comment, but how
> about handling such callback in lua a la hooks in Emacs?  The hook
> author can decide whether they want to ask that it be at the front of
> the list, the back of the list, or (default) don't care.  Of course
> there are no guarantees due to multiple packages requesting the same
> thing, but at least the basic options would be provided.

[Tongue in cheek]  I hope Taco isn't reading this, because his view is:
    JavaScript is *way* off topic for this list.
and he might think the same about Emacs Lisp.

Seriously, it is a good suggestion.  If not an example to follow, it can 
be an example to learn from.  (And in my view the same goes for JavaScript.)

-- 
Jonathan