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RE: Fwd: Re: RESEND: Extending xhtml? How?

From: Brad Cox <bcox@virtualschool.edu>
Date: Sat, 24 Jan 2004 11:38:16 -0500
Message-Id: <p06001814bc38479fa71e@[68.50.169.130]>
To: "Jack Lindsey" <tuquenukem@hotmail.com>, xmlschema-dev@w3.org

At 10:04 AM -0500 1/24/04, Jack Lindsey wrote:
>I think people were slow to respond because they were confused about 
>what you are trying to achieve.

Thanks, Jack. You're probably right. Its a confusing thing I'm trying 
to do: make it possible for any faculty (willing to learn XML) to 
develop programming environments that support active learning, by 
which I mean environments that are fully *programmable* (even by 
faculty, if you can imagine such a thing! ;) to build active learning 
environments on the web. Its hard to explain concisely: see 
http://virtualschool.edu/edu for what action learning environments 
involve and how students respond to the approach. The ALE system 
itself is at http://virtualschool.edu/ale.

XMLSchema is needed as for XML *validation* only, via a standalone 
validator (I use several of the common ones), mainly because the 
run-time servlet reports errors one by one which gets tedious. The 
servlet does its own validation while converting XML to JavaBean 
models when an XML file changes. It report any XML problems to the 
screen as it does this.

The servlet rewrites the XML/XHTML to convert my special markup with 
Velocity macro calls, which emit XHTML (I know, I could have used 
XSL; JDOM does the same thing). Bottom line, browsers only see plain 
old XHTML. The PRIME requirement is that it work with any browser a 
student might have; I've no patience for debugging browser 
incompatibilities when teaching and go to great lengths to stay well 
clear of the bleeding edge; JavaScript and Applets being two specific 
examples of things that always cause incompatibility headaches. My 
pages may look plain without all the eye candy, but the work with any 
browser a student might throw at them. By design.

XMLSchema is only needed for the separate validation tool, which will 
only be used by those that get impatient with the 
one-error-at-the-time XML validation I get from JDOM. I'm not really 
sure the validation tool is necessary and may well punt on the whole 
idea, which is starting to look like a whole project in itself. I 
never imagined proper validation would be so HARD. I've spent more 
time on that single aspect than it book to build the application 
itself.

Java was used to build the ALE servlet architecture. Faculty doesn't 
see this directly. They mix Jakarta's Velocity language statements 
(JSP alternative) to insert executable code in their XHTML. For 
example <body><h1>Welcome $person</h1></body> shows "Welcome BradCox" 
when I'm logged in. There are also #if, #foreach, #set, #macro 
definitions, and so forth; a reasonably easy to use programming 
language that is able to traverse JavaBean models quite well. I've 
also experimented with Jython and Ruby in that role.

>If you want your students to access this material through standard 
>browsers, there is no point in extending XHTML, unless you want to 
>build a custom browser to handle the extensions.
>
>If you want to present your custom data structure vocabulary to a 
>browser, you should be able to use XML files, validated against an 
>XSD schema, and directly styled for the Web by CSS (Cascading Style 
>Sheets).  Unfortunately, unlike Mozilla and Opera, the browser with 
>90% market share can't handle this.  Therefore, the 
>industrial-strength, cross-browser solution is to include a 
>reference to an XSLT stylesheet in your XML file, which transforms 
>the XML into XHTML, and includes a reference to a CSS stylesheet, 
>allowing you to keep cosmetic tweaks to presentation separate from 
>content structure.
>
>You mention an interactive question-and-answer feature.  XHTML has 
>basic form/input features which can be managed by client-side 
>JavaScript or server-side CGI/Perl scripts, and Curt mentioned 
>Xforms.
>
>You also mentioned an affinity for Java.  You could put <object> 
>tags in your XHTML which would invoke and pass parameters to Java 
>applets.
>
>So many options, so many technologies, so little time!
>
>HTH  Jack

-- 
Brad J. Cox, PhD, 703 361 4751, http://virtualschool.edu
        http://virtualschool/ale Action Learning Environment
http://virtualschool.edu/mybank Digital Rights Management System
    http://virtualschool.edu/jco Java Cryptographic Objects (JCO)
   http://virtualschool.edu/jwaa Java Web Application Architecture (JWAA)
  http://virtualschool.edu/java+ Java Preprocessor (Java+)
Received on Saturday, 24 January 2004 11:40:01 GMT

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