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- From: Len Bullard <email@example.com>
- To: firstname.lastname@example.org
- Date: Sat, 13 Nov 1999 00:08:20 -0600
Thanks Tim. I asked the question quoted, so if no
one takes offense, I want to continue this on
both lists. See below. I have edited the
post to reply. See Tim's post.
Background: The X3D community is engaged
in working out the binding of VRML97 to an XML
application via an IDL. We have serious concerns
about the fluidity of the schema and datatype
situation. Use of encapsulated XML/X3D is demonstrated.
Integration into an aggregate namespace is still by
<object ..> in demonstrations and examples.
X3D is now at the stage where the initial
designs for the DTD are stable and the first
drafts for binding UTF-8 VRML and the XML are
being written. There are other issues such
as the lack of array datatypes which will
compromise the use of XML schemas for X3D schemas.
Sebastian Schnitzenbaumer of Stack Overflow, a member of the HTML WG
Len Bullard, Intergraph Public Safety, a member of the
X3D Contributors Group:
Len: There are some integration issues to be worked out for
example if a user customizes a DTD to be a conformant subset, is the
namespace the same? If the user customizes a DTD but makes some changes
that affect names, how does the user indicate a variant? Is is useful
to indicate the variant?
Sebastian: This is something the HTML WG has explored in great detail.
Modularization of XHTML is the framework for the HTML WG and
other parties to organize the development of XHTML, that's why I
sometimes use the nickname "XHTML Development Kit".
The subsets, extended subsets and variants versus namespace
issue was a problem the HTML WG needed to solve.
One might ask, why modularization in the first place?
Len: Hmm not me. I am a believer. Got the MMTT t-shirt. On
to the code:
Sebatian: Here is the model the HTML WG is currently developing:
Basis is HTML 4.0, a monolithic, stand-alone ML.
XHTML 1.0 is just the same thing in XML clothing, same
functionality but XML notation, still one big thing.
Len: So, XML, A NOTATION, is a type. It is the lexical
and semantic description of a namespace. Functionally,
an object handler and schema for it?
Sebastian: XHTML 1.0 introduces the XHTML namespace, without implying
Len: Why not?
Sebaatian: (NS URI is now "http://www.w3.org/1999/xhtml" BTW).
Len: Thank you.
Sebastian: Modularization slices XHTML 1.0 into a dozen "modules".
a markup language as a cake. If you are sure that someone won't
take the whole cake but only some slices, then it is better to define
"default cuts" instead of letting everyone randomly cut the thing into
Len: I agree. But mostly, I like it because it is
very easy to slice parameter entities and element and attribute
type declarations into hyperlinked name sets and/or dropdowns.
I like to define my own defaults.
Ten years ago, we had systems that let us associate
style to markup without the need to downtranslate.
That is what we need now. It makes the treeviews work.
I don't want to navigate the structure tree of the
screen containers. I want to navigate the names of the
datasets. I think there will be a big seachange when
the web lets go of seeing the screen in terms of
one DTD, but as a composite of many in familiar controls.
Sebastian: If Vendor A says I'm using slices X, Y, Z and Vendor B
says Y, Z, P, then Author C will know the Y and Z is the same in
both Vendor A's and Vendor B's implementation.
Len: How? Common schemas? Namespaces don't name anything.
They enable prefixing. Prefixing is the lexical means
to weave members of mutliple trees. What trees are so
defined and where? Schemas? What are the rules of the
aggregate? What are the logistics?
How do I know that Vendor B'sB and VendorA'sB work
the same? Conformance tests? Who defines it?
Who pays for the lack of conformance?
Sebastian: Modularization of XHTML is the "module repository". In the
repository, there are more modules than a single version of XHTML
can use, for instance, there are two forms module (HTML 3.2 forms
and HTML 4.0 forms) and two tables modules, etc.
Len: Repositories. M-Language communities like chat communities
integrate by common interest. Let a thousand flowers bloom,
but if you ask any gardener, it takes a lot of work to get
25 through the season. Ecom-ecology. Give them tools and
get out of the way while the business hackers learn to
apply them to create document databases instead of pages.
Sebastian: XHTML 1.1. is the same as XHTML 1.0, but the DTD is not
monolithic, rather a specific combination of modules taken from the
module repository that aims to be a close match to XHTML 1.0.
Len: The XHTML 1.1 design uses the name space of the parameter entity
and a dot convention to assert a modular definition. See
AECMA 2000, MIL-M-28001, MIL-D-87269 for prior art. Oster used the dot
convention. All were tested and found useful. Standard.
The DTD approach to modularization in XHTML is top flight
for that form of defintion. This works for DTD maintenance.
As a means of specifying interoperable systems, it is only
so so. It is adequate name management.
Sebastian: Now comes the interesting part. The document "Building XHTML
Modules" is the tutorial for any party (not only W3C) to create
"XHTML conforming modules", a how-to guide on creating new
modules similar in design to the those modules found at W3C's
Len: Yep. he way to go..
Sebastian: To answer the namespaces question, let's play through a
Consortium releases module repository together with a specific
combination known as StandardML. StandardML uses 12 of 15
modules of the module repository. StandardML's 12 modules
include 8 *mandatory* modules. All 15 modules of the module
repository belong to the "StandardML namespace". Consortium is
in control over StandardML namespace.
Len: If you insist. My thought is, give them the tools to
define their own namespaces and figure out among themselves
how to relate them. Not that XHTML is not important.
It absolutely is. The W3C has a very good module repository.
New DTDs may work for processes where rendering
in a document model such as XHTML is not the best medium
or always the host. Sometimes it is the thing on
the wall next to the h-anim smoking the cigarette.
Or, it is a very simple XHTML, and a very complicated
set of islands. Language spaces defined as module
repositories is just a way of satisfying a systemic
issue with the shared definitions: networks come
down to registries.
XHTML is there in role as a page description language,
but so are very cool new markup languages to use with it.
I've played with VML. Good logos. Good basic 2D. Really easy
because it is JustMoreTags. X3D is exciting to
me because personally, I've waited a long time for
a medium in which the entire range of hypermedia
was expressible in markup. These are exciting
times for some of us. Didn't think it would ever come.
Using data islands and different rendering languages
that can be combined by effect and animation is fantastic.
Sebastian: As an example, here is a sample file of XHTML-FML, an XHTML
family member using XHTML 1.1 without the HTML 4.0 Forms
module but instead with an additional namespace of five new
Forms Markup Language modules:
<!DOCTYPE html PUBLIC
"-//OVERFLOW//DTD XHTML-FML 1.0//EN"
<meta name="generator" content="Mozquito Factory 1.0" />
Check http://www.mozquito.org/factory to see the implementation.
Len: That is very cool.
Len: Thank you very much for taking the time to answer me.
Your description is lucid, and easy to understand.
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