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Date:         Wed, 28 Aug 1996 21:06:07 +0200
From: Manfred Maennle <maennle@IRA.UKA.DE>
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Subject:      A More Flexible Section Structure
Status: R

I am now two weeks subscribed to the LATEX-L@RELAY.URZ.UNI-HEIDELBERG.DE
mailing list but didn't receive any mail yet. (I hope this list is not dead.)
Nevertheless I want to bring my reflections about "a more flexible section
structure" up to discussion. Since I am only two weeks subscribed I don't
know whether this topic was already discussed. If so, I apologize for
wasting bandwith and disk space. But now, here are my thoughts:


A MORE FLEXIBLE SECTION STRUCTURE


Abstract: I propose the introduction of a more flexible section structure.
In addition to the "horizontal mobility" I propose a "vertical mobility" of
sections.


1 State of the Art

Until now, LaTeX supports the hierarchical section structure (which is inherent
in every docment) by sectioning commands like \chapter, \section, etc.

                 document (title)
                       |
1                     part
                    /     \
2              chapter      chapter
            /     |    \       |   \
3      section  sect   sect   sect  sect
                      /   \
4                subsect  subsect

By the mechanism of automatic labelling one has a vertical mobility of the
sections. This has the advantage that (with the help of my editor's cut & paste
function) one can for example swap two sections or add another one without
having to relabel everything. This mobility is WITHIN a hierarchy level: I can
swap two \chapters but not a \chapter and for example a \subsection.


2 The Problem

In large documents I sometimes have the need for a vertical shift of a section
and its subsections. So I would also like a mobility BETWEEN the different
hierarchy levels. This is for example when I start writing a document with
a first layout of the section hierarchy. Now if a section, say section 1.3,
becomes more important or too large and I want to spend a whole chapter for
it, I have to change \section to \chapter and, that's the problem, change ALL
\subsections, \subsubsections, etc., to the command of the higher hierarchy
level. This need will certainly not appear at small documents (and if, it would
be no problem to change a few \subsections) but it does appear at large
documents (at least, I have sometimes that need :-)


3 A Solution

The solution is not having an ABSOLUTE hierarchy level (e.g. \chapter is always
level 2) but having a RELATIVE hierarchy level. I will use the term "passage"
for this universal sectional unit. A document could then be structured like:

---------------------------------------------------------------------------
\title{Document's title\label{doc}}
\passage{doc}{Introduction\label{intro}}   % chapter 1
[...]
\passage{doc}{The problem\label{problem}}  % chapter 2
\passage{problem}{A subproblem\label{sp1}} % section 2.1
[...]
\passage{sp1}{A subsubproblem}             % subsection 2.1.1
[...]
\passage{problem}{Another subproblem}      % section 2.2
[...]
\passage{doc}{A solution}                  % chapter 3
[...]
---------------------------------------------------------------------------

Every passage header points (with its first argument) to the related header of
the upper level. For both, horizontal or vertical displacement, you only have
to change one pointer. (All "subpassages" move together with the passage they
point to.)

There is no additional TeX run necessary, since all passages that are pointed
to must preceed its "subpassages". (Therefore, already at the first run the
level of every passage is obvious.)


4 Discussion

The proposed section hierarchy has the advantages
 + more flexible document structuring: vertival moving of passages
 + unlimited hierarchy depth

and the disadvantage
 - when regarding the source LaTeX file, you cannot "see" the passage's level
   (i.e., you cannot see from the structure command whether it's a chapter,
   section, or only a subsection)
 - must be implemented :-)

I see no reason why not to test the proposed section hierarchy by providing
the sectioning command in an additional package (except that I can't implement
this because of my lack of TeX knowledge). If successful, one can think of
having both, the known sectioning commands and the new one in parallel.


Have fun,
    Manfred
____________________________________________________________________________
Manfred Maennle http://goethe.ira.uka.de/people/ | You can do what you want,
Institut fuer Rechnerentwurf  und Fehlertoleranz | but you cannot  want what
Universitaet  Karlsruhe  (TH),  D-76128  Germany | you want.  (Schopenhauer)
Phone:  +49 721 608 3910,   Fax:  +49 721 370455 | --- pgp key available ---