# [Dev-luatex] vpack_filter shipout mode?

Hans Hagen pragma at wxs.nl
Fri Aug 20 15:57:45 CEST 2010

```On 20-8-2010 2:16, linuxss wrote:
> Hi, Hans,
> I've got almost the same output, as I used 'pre_output_filter' callback
> and a function on a \output command.
>
> 1)
> \newtoks\oldoutput
> \oldoutput=\expandafter{\the\output}
> \output{
> \directlua{node_check(tex.box[255], 'shipout')}
> \the\oldoutput
> }
>
>
> and I can't see here table and page number nodes.
> pre_output_filter sounds like the all output should be prepared :)
> if I use 'vpack_filter' i see all the nodes of the page.
>
> so that means, that 'vpack_filter' is closer to shipout then
> pre_output_filter?
> I thought is has to be in reverse :)
>
> question: when the pages and table are inserted into \box 255?

I have no clue what your node_check does.

Anyhow, there is no concept of a page number node and table node, a
pagenumber is just a bunch of glyphs and a table becomes a collection of
boxes (hlist/vlist) nodes.

If you recurse over the node list then you will undoubtely see them,
just as regular full tex tracing can show them.

When pages are inserted depends on your macro package ... normally the
pagebuilder does that (regular tex code, nothing built into the engine)
and the same is true for a table, once the alignment is done it becomes
boxes in the mvl or wrapped into some other box and again it ends up in
the mvl. So, no magic there.

Hans

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