Quick overview of current topic definition with questions for discussion

Figuring it might be easier to discuss
something higher level than the actual DTD files...

Here's the current (rough) structure
of the strawman:

Topic specialization/customization

----------

Can be specialized by defining a new
topic element and a body element that incorporates section modules in a
specific sequence/organization. Section specializations are designed to
be easily sharable across topic specializations. Each section specialization
can include further-specialized block elements if needed.

Can be extended by incorporating domains
at the phrase or attribute level.

Attributes and content model behaviors
can be modified by redefining attributes and declaring appropriate constraints:

Out of the box constraints available
are:

filters - controls whether @props attribute
and any of its specializations are available

reuse - controls whether @id and @conref
are available on blocks

variable-content - controls whether
@keyref is available on <ph> , <image>, <data>

localization - controls whether @dir,
@xml:lang, and @translate are available on most elements

nested-blocks - controls whether lists
can be nested

Q: in this model, you can easily
share specialized section designs across topic specializations, but you
cannot easily share specialized block-level designs (eg a specialized table)
across section specializations. Is that acceptable? The alternative is
to either open up full domain specialization for blocks as well as phrases,
 or create a new method of extension that is parallel to domain extension
but leverages the basic content model entities instead of creating redefinable
entities for every mention of every element.

Q: do we want to open up/doc redefining
other content model entities arbitrarily, eg to add your own elements back
in from base DITA? 

Q: do we want to break DITA here, by
allowing the introduction of specialized elements through entity redefinition
as well? What would be the processing model implications?

Q: do we want to also consider breaking
DITA in the way we declare constraints, to make it simpler and more flexible?
For example adding in new elements, just declare them in the constraints
attribute as (+xxx); removing existing elements, same thing but -xxx.

Topic content model

----------

The following common content models
are controlled with entities:

common-inline: inline text, ph and its
specializations, image, and data

all-inline: same as common-inline plus
xref, data, and data's specializations

common-blocks: p, ul, ol, dl, pre, object,
and object's specializations

all-blocks: same as common-blocks plus
simpletable

nested-blocks: same as all-blocks (but
only used in the content model of other blocks, so it can be redefined
to turn off block nesting)

Structural elements - all elements have
default class attribute

topic - requires @id, plus defaulted
values for ditaarch and domains

title - contains common-inline, has
 entity-controlled localization attributes

shortdesc - contains common-inline,
has  entity-controlled localization attributes

prolog - contains any number of data
elements

body - contains all-blocks, followed
by any number of sections; has  entity-controlled localization attributes

section - contains optional title, followed
by all-blocks; has  entity-controlled localization, filters, reuse
attributes

Block-level elements (except table,
object) - all elements have default class attribute, plus entity-controlled
localization, filters, reuse attributes

p - contains all-inline

ul/ol - contains any number of li

li - contains nested-blocks

dl - contains any number of dlentry

dlentry - contains dt, dd

dt - contains all-inline

dd - contains nested-blocks

pre - contains all-inline; has defaulted
xml:space attribute

Table elements  - all elements
have default class attribute, plus optional localization, filters, reuse
attributes

simpletable - contains optional sthead,
any number of strow; 

sthead/strow - contains any number of
stentry

stentry - contains common-blocks

Object and image elements - all elements
have default class attribute

object - contains optional desc, followed
by any number of param; has data, type, height, width, name, usemap attributes
plus entity-controlled localization, filters, reuse attributes

desc - contains common-inline, has  entity-controlled
localization attributes

param - contains nothing, has required
name and optional value attributes

image - contains optional alt element;
has href, height, width attributes plus  entity-controlled localization
and variable-content attributes

alt - contains common-inline, has  entity-controlled
localization and variable-content attributes

Inline elements

ph - contains all-inline; has entity-controlled
localization and variable-content attributes

data - contains number data elements;
has optional name/value attributes, plus entity-controlled variable-content
attributes

xref - contains common-inline; has href,
format, scope attributes, plus entity-controlled localization and variable-links
attributes

Q: object has been defined as an entity
to allow video and audio to be introduced as specializations; do we want
to just ditch object, and go with video/audio from the start?

Q: this list doesn't include <note>
- I know that's been controversial, and I'm open to including it - do we
want to map it to an html5 <aside> element? Maybe even rename it
to that, to broaden its potential usage?

Q: this is using simpletable, elsewhere
I've tried a simplified form of CALS. Does anyone have a preference? Either
way we're not allowing any complex table features - no column spanning,
etc. Maybe we start with simpletable, but allow for the possibility of
people reintroducing full table during customization? I almost wish we
could just go with HTML tables here for the sake of easy mapping to HTML5,
but that would really break all our existing DITA tooling.

Michael Priestley, Senior Technical Staff Member (STSM)

Enterprise Content Technology Strategist



http://dita.xml.org/blog/michael-priestley