On 08/29/2010 02:59 PM, Patrick Gundlach wrote:
Hi,
I have this box:
\setbox0\vbox{x}
when I analyze the nodelist, I find a somewhat strange hlist node:
nil : hlist 0> which is referenced from the whatsit (local_par)/prev node pointer. See "n30" in the attached image. Is it safe to ignore this hlist?
(is this the parindent box? - answer from the other mail?)
Oh, right. No, it is not. The 'next' pointer is the parindent box. The prev of local_par is nonsense (it originally points to a temp node that was the current head, but temp nodes often end up junk after they are no longer needed). I should clear that field when the head is split off, but it will take some time before I can find the correct location. Just ignore it, please.
Another related question: sometimes I come across "nested_list" and "temp" nodes. Can I ignore these as well?
I wonder why two hlists point back to the same nested_list (n155).
Same thing happens here. In general, the back pointer of the first item of a list of nodes contains a pointer to a temp node that was created to start the current chain (discretionary sublists are the exception). Best wishes, Taco