?SPAM? - Re: [texhax] Orphan section heads

[Philip TAYLOR]

Dear Uwe -- Many thanks for your suggestion;
I suspect that one "\expandafter" got lost in
transit (as it stands, you are trying to redefine
\expandafter rather than \verbatim !), but modulo
that, it seems to work as you intended :-)))

Very many thanks, and I am cc'ing Robin who may
wish to retrofit something similar to the TUGboat
macros.

** Phil.
--------
Uwe Lück wrote:

> Dear Phil and all involved,
> 
> the diagnosis is rather simple. The LTUGproc subsections
> are embedded into the following text (the "next skip" is negative).
> The authors of \@startsection seem not to have thought of
> the possibility that an embedded heading could precede a
> paragraph environment. In Standard LaTeX, the same would happen
> with \paragraph. The environment is even likely to set a penalty
> that overrides the \clupenalty (a general TeX problem).
> 
> I don't find good ways out so easily.
> 
> In your case I would suggest:
> \makeatletter
> \def \expandafter \verbatim \expandafter{\expandafter
>   \@beginparpenalty\expandafter\@M\verbatim}
> \makeatother
> -- This should also prevent the \skip in \@verbatim
> from breaking.
> 
> One may also try the samepage trick or
> \parbox{\columnwidth}, I am not experienced with that.
> 
> Best Regards,
>   Uwe.
> 
> At 16:32 24.10.05, Philip TAYLOR wrote:
> 
>> Dear Uwe -- the relevant part of the log, as requested,
>> as 1435 lines, and is at
>>
>>         http://personal.rhul.ac.uk/chaa/006/log.log.txt
>>
>> the input was :
>>
>>         \tracingmacros = 1
>>         \subsection {explanation.cases}
>>         \begin{verbatim}
>>         0
>>         1
>>         2
>>         \end{verbatim}
>>         \tracingmacros = 0
>>
>> Note that this is a boundary case; one fewer lines in the
>> verbatim text and it is all fitted on the current page.
>>
>> Looking at the first few lines of the log, I fear this
>> is complicated (and perhaps even caused) by TUGboat's
>> intervention : I am therefore cc'ing Barbara, who may
>> wish to look at her part of the code ...
>>
>> ** Phil.
>> --------
>> Uwe Lück wrote:
>>
>>> Sorry, sorry, sorry ... those orphan section headings are
>>> still a mystery to me, and I haven't found any LaTeX bug
>>> as claimed (they are at best "weaknesses", yet LaTeX
>>> cares about them). \@startsection, through \@xsect,
>>> indeed puts \penalty10000\vskip... to the list (in the vertical
>>> case) and immediately following \vskip's aren't possible
>>> points to break (TeXbook p. 110). The \write from \label
>>> (or \addcontentsline; similarly \mark...) after \@startsection
>>> neither enables breaking at a following \vskip -- the latter is
>>> preceded by a \nobreak from \protected at write. This is what
>>> \@nobreaktrue is for.
>>> Phil, you might put \tracingmacros=1 before \subsection and
>>> \tracingmacros=0 after \end{verbatim} and send the .log to me.
>>> Similarly Michael Barr / Florian Knorn -- it should be possible
>>> to delete confidential material from the .log (unless your bugged
>>> sectioning macros are confidential).
>>> -- Uwe.
>>>
>>>> I bet I've got it, at least concerning Philip Taylor's sketch
>>>> of an example. I see two bugs in LaTeX that might be
>>>> responsible or raise the danger of orphan headings.
>>>>
>>>> At 16:12 21.09.05, Philip TAYLOR wrote:
>>>>
>>>>> Hmmm, sadly I can now demonstrate that it
>>>>> is only too easy to get an orphaned subsection
>>>>> head : this accomplishes it for me, though
>>>>> I very much wish that it didn't :-(((
>>>>>
>>>>>         \documentclass [final]{ltugproc}
>>>>>         \usepackage {graphicx}
>>>>>         \hfuzz = 1\jot
>>>>>         \overfullrule = 1\jot
>>>>>         \hyphenation {legit-imately}
>>>>>         \flushbottom
>>>>>                 . . .
>>>>>         \subsection {byz-data.dat}
>>>>>         \begin{verbatim}
>>>>>                 . . .
> 
> 
> _______________________________________________
> TeX FAQ: http://www.tex.ac.uk/faq
> TeX newsgroup: http://groups.google.com/groups?group=comp.text.tex
> Mailing list archives: http://tug.org/pipermail/texhax/
> More links: http://tug.org/begin.html
> 
> Automated subscription management: http://tug.org/mailman/listinfo/texhax
> Human mailing list managers: postmaster at tug.org
>