# [Dev-luatex] Just noticed something...

Hans Hagen pragma at wxs.nl
Wed Apr 4 09:14:19 CEST 2007

David Kastrup wrote:
> In the messages from the tex.tex run, I got overfull box messages like
> the following:
>
> Overfull \hbox (12.40152pt too wide) in paragraph at lines 21018--21025
> []\tenbf 836. \tenrm It is not nec-es-sary to cre-ate new ac-tive nodes hav-ing
>  [] greater than \$[] +|
>
> \hbox(6.94444+1.94444)x469.75499, glue set - 1.0, direction TLT
> ..\whatsit
> ...\localinterlinepenalty=0
> ...\localbrokenpenalty=0
> ...\localleftbox=null
> ...\localrightbox=null
> ..\tenbf 8
> ..\tenbf 3
> ..\tenbf 6
> ..\tenbf .
> ..etc.
>
> That whatsit has to go.  Absolutely.  When the user is explicitly
> assigning values to \local* variables, placing a whatsit at the point
> of assignment is fine and expected.  It is even conceivable to place a
> whatsit at the start of the current hlist _when_ we assign to \local*
> in the middle of the list.  But we can't go peppering the lists with
> whatsits when we are not asked for it.  It will break far too many
> existing packages.  Unless we find a way to make whatsits transparent.
> But the combination
>
one of more whatsits does not really matter, since a macro package
writer cannot foresee what users put in their docs and so whatsits can
show up all over the place anyway

on the todo list for luatex is an additional repertoire of \un*
primitives to deal with unrolling boxes, but more powerful is that at
some point we can use lua to manipulate such lists

the current priority lies with fonts and being able to typeset high
quality arab, and given idris (oriental tex) demands i bet that
solutions for this whatsit stuff will show up eventually

anyhow, package compatibility is not high on our agenda; if a package
does not work any more, bad luck ... adapt the package ... or use pdftex
1+; users have to live with the fact that macro packages have to adapt
(and i'm rather optimistic about that ... see how packages adapted to
xetex); we will try to make luatex as compatible as possible, but not at
all costs

in a sense this is not related to luatex, because omega also had this; i
can even imagine that  omega packages will break with this  whatsit not
being there -)

Hans

-----------------------------------------------------------------