DOCBOOK: RFE for further modularization of hierarchy; please comment

[Michael Smith <smith@xml-doc.org>]

I just filed an RFE proposing further modularization of the DocBook
hieararchical elements (the stuff in the dbhier.mod file).

  http://sourceforge.net/tracker/index.php?func=detail&aid=477073&group_id=21935&atid=384107

I hope anyone interested can take some time to comment on it here.

Briefly, the idea is to take content models from the dbhier.mod file
and put them into separate files/modules, like in this diagram:

  https://sourceforge.net/tracker/download.php?group_id=21935&atid=384107&file_id=12733&aid=477073

and here, as text:
  
  * sections module:        Section, Sect1-Sect5, Simplesect
  * reference page module:  Refentry and its child hierarchy
  * article module:         Article (and Articleinfo)
  * navigational          
    components module:      ToC, LoT, Index
  * supplemental          
    components module:      Appendix, Glossary, Bibliography
  * book and set module:    Book, Set, Part, Partintro, Reference,
                            Preface, Chapter, Dedication, Colophon

Along with making the separate modules, we'd also need to add
parameter entity switches for turning on or turning off each of them.

The rationale is that it'll make it easier for DTD implementors/
customizers to mix and match or ignore whatever building blocks from
the standard hierarchy they choose -- so they can use only the
hierarchical bits they need and ignore the rest. It's just another
useful hook to add to all the existing hooks that DocBook has for
facilitating customizations.

Regarding any effects on document authoring and validation: I think it
would be a transparent change. It should be 100 percent backward-
compatible -- anything that validates against the 4.1.2 DTD should
validate against this modification.

If you want to try it out, you can grab a modified version of the
4.1.2 XML distribution, with the proposed modules added.

  http://sourceforge.net/tracker/download.php?group_id=21935&atid=384107&file_id=12731&aid=477073