[Dev-luatex] \lastnodetype not working as expected in LuaTeX

Hans Hagen pragma at wxs.nl
Mon Jun 11 00:01:10 CEST 2012


On 10-6-2012 23:44, Patrick Gundlach wrote:
> (More from Frank Mittelbach on this subject - he is not subscribed yet but will be ASAP)
>
>
> I'm now fairly certain this this is a bug in the current implementation of linebreak_filter. What seems to happen is the following: when TeX builds a list (in this case a vertical list) it keeps track of it through a pointer to the head and to the tail of that list. Now when a paragraph is broken into lines those lines get appended to the current vertical list by the linebreaking algorithm and the tail pointer is updated to point to the new end of this list. However, if thelinebreak_filter replaces TeX's algorithm the material from that filter is appended to the list but the tail pointer is not changed. Thus in my example it still points to the node before the paragraph (which happens to be nil as the paragraph starts the vbox).

fyi: there are some more pointers not being updated/adapted and that's 
part of a todo cleanup of the par and page builder related code (the 
same is true for updates of totals and goals)

Hans

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