# [luatex] behavior of buildpage_filter ?

Frank Mittelbach frank.mittelbach at latex-project.org
Sun Apr 3 23:17:06 CEST 2016

Am 03.04.16 um 21:48 schrieb Frank Mittelbach:

>
> looks like the issue is not just resolved by looking for pre_box, box,
>

does anybody has a good idea for a workaround here?

What I like to do is to look at all material that gets contributed to
the main vertical list (just before it actually is contributed) and
possibly change some of it.

Now ignoring the 4 context states as suggested by Hans earlier doesn't
work as "box" is a valid state if you put a \vbox or \hbox directly onto
the main list.

On the other hand processing the "box" state doesn't work either as it
will then result in processing the material more than once.

The only kludge I came up with so far is to set a global variable
doing_linebreaking=true in the pre_linebreak_filter and setting it to
false in the post_linebreak_filter  and then testing for that variable
together with context=box in buildpage_filter but

a) that IS a kludge
b) not even sure I catch all cases with it

anybody any better idea?

thanks
frank