# [Dev-luatex] Strange behaviour

Taco Hoekwater taco at elvenkind.com
Mon Feb 2 10:00:46 CET 2009


Elie Roux wrote:
> Hello,
>
> here is an example of some behaviours I find quite strange... It is a
> really short and simple example in plainTeX. It shows that if we have
> set \localleftbox or \localrightbox once, every line will have two more
> (empty) nodes. I think this behaviour is quite uncoherent, because
> packages (like GregorioTeX) set some \localleftbox and \localrightbox
> and then unsets them, so if someone wants to count the nodes of a line,
> this result will depend if he has a score in his document or not, even
> if he counts the nodes of a line that has nothing to do with a score...
> I think it would be better if these empty nodes were suppressed...

The problem is that you can not truly unset the \local{right,left}box
because they were meant for partial use within just a few lines inside
a paragraph.

\localleftbox = {} just assigns an empty \hbox{}, which is not the same
as nothing at all. The only way to get rid of the content is via
grouping.

I have options:

1. delete the empty nodes as you propose and/or make {} mean: unset it
2. switch the input syntax to \box-style format with an explicit \hbox
(this has my preference)
3. do nothing

Best wishes,
Taco