Re: Good stuff on XHTML modularization
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. len ****************************************************8 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 namespaces. 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 versioning 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". Think of 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 pieces. 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 module 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 module repository. Len: Yep. he way to go.. Sebastian: To answer the namespaces question, let's play through a scenario: 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: <?xml version="1.0"?> <!DOCTYPE html PUBLIC "-//OVERFLOW//DTD XHTML-FML 1.0//EN" "http://www.mozquito.org/dtd/xhtml-fml1.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xmlns:x="http://www.mozquito.org/xhtml-fml"> <head> <title>Untitled</title> <meta name="generator" content="Mozquito Factory 1.0" /> </head> <body> <x:form> ... </x:form> </body> </html> Check http://www.mozquito.org/factory to see the implementation. Len: That is very cool. Regards, Sebastian Len: Thank you very much for taking the time to answer me. Your description is lucid, and easy to understand. Regards, Len xml-dev: A list for W3C XML Developers. To post, mailto:xml-dev@i... 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