Re: [WEB400] XML/XSL

["Nathan M. Andelin" <nandelin@xxxxxxxxxxxxxxxxxxx>]

> From: "Metz, Zak" <Zak_Metz@xxxxxx>
> That's just it. It's not necessarily a browser. It may be a
> cell phone or a PDA, or something else tomorrow.
> I don't want to send the same HTML to a device
> that has a screen 200 pixels wide (or whatever)...

Using the HTTP protocol, the client identifies itself and its capabilities
through the USER_AGENT and other strings which are passed to your server.
Your program is able to make a decision about what to return to the client.

What will you return?  What are your options?  Return a program (XSL) and
formatted data (XML), then have the client itself generate either HTML or
WML?  Or, have the server generate the HTML or WML depending on the client's
capabilities?

XSL may be characterized as a program because it contains variables, flow
control, conditional logic, character and numeric expressions, and so forth.
Aaron pointed out that an interpretive runtime environment for XSL
(Transformer Factory) is available in Java.

An XSL file is actually much like a Net.Data macro, Active Server Page, or
Java Server Page in that formatted text (HTML or WML) is embedded in the
same file as the control logic.  The Transformer Factory is an
interpretative runtime environment.  The similarities between XSL, JSP, ASP,
and Net.Data are striking.

If your site supports WML as well as HTML clients, it seems to me that XSL
forces you to write two (2) programs to support them - one XSL program for
the HTML client, another XSL program for the WML client.  Additionally you'd
probably write a program to transform an SQL result set into XML.

Associating the term "style sheet" to XSL makes it sound easier than writing
a program.  But is it?  I'd say that it just increases the programming
workload.  It seems to me that if you do the SQL to XML, and XML to ??ML
transformations on your server it increases the server workload too.

Or, am I missing something?

Nathan M. Andelin
www.relational-data.com