HTML forms in Docbook

["Bob Stayton" <bobs@sagehill.net>]

I'm following up on my action item to research where the
HTML <form> element could be added to the DocBook DTD
to permit more widespread use of form in HTML output.

In XHTML 1.0, the form element is permitted inside the following
HTML elements that DocBook is likely to generate:

blockquote
body
dd
div
li
td
th

Just for completeness, form is also permitted inside the following XHTML
elements, which I
consider not relevant to this discussion:

applet
del
fieldset
iframes
ins
map
noframe
noscript
object

Currently the %forms.hook; parameter entity that allows
the form element to be added to the DocBook DTD is seen
only in the divcomponent.mix parameter entity.  This PE
is in turn used as part of the content model of the
following DocBook elements:

appendix
article
chapter
partintro
preface
sect*
section
simplesect

Being in the divcomponent.mix means that form is a sibling of
lists, formal and informal objects, para, linespecifics, admonitions
and a few others.  But it also means that a form cannot appear *inside*
any of these elements.  That is the limitation that some would like
to overcome.

At the same time, there is no desire to make form an inline,
because that is not supported in HTML.

So I investigated how to integrate form into the content of
more elements while at the same time avoiding any inlines.

I am recommending that we add the form hook to the following
DocBook parameter entities:

admon.mix
component.mix
example.mix
figure.mix
listpreamble.mix
qandaset.mix
refcomponent.mix
sidebar.mix
tabentry.mix

These PEs are all mixes of various block-level elements,
and no inline elements, so adding form  would be consistent.

Here is a more detailed list of what elements would then be
permitted to contain a form in some part of their content
model.  For those marked with a (p), form can only appear
in the preamble part (e.g., the text between the title of
a bibliography and its first biblioentry).

admon.mix
   caution
   important
   note
   tip
   warning

component.mix
   bibliodiv  (p)
   bibliography  (p)
   blockquote
   callout
   glossary  (p)
   glossdiv  (p)
   index  (p)
   listitem
   msgexplan
   msgtext
   procedure  (p)
   setindex  (p)
   step
   taskprerequisites
   taskrelated
   tasksummary

example.mix
   example
   informalexample

figure.mix
   figure
   informalfigure

listpreamble.mix
   itemizedlist  (p)
   orderedlist  (p)
   variablelist  (p)

refcomponent.mix
   refsect1
   refsect2
   refsect3
   refsection
   refsynopsis

sidebar.mix
   sidebar

qandaset.mix
   answer
   qandadiv  (p)
   qandaset  (p)
   question

tabentry.mix
   entry

Adding form to these parameter entities would noticeably expand the
opportunities
for using form in DocBook.

Bob Stayton
Sagehill Enterprises
DocBook Consulting
bobs@sagehill.net