First experiences with XSL

[Istvan Cseri]

Of course it is easy for any programmer to write an XML parser, implement an
XML object model, implement the XSL algorithm, print out HTML, etc. This is
actually great, it shows that the design of these languages and algorithms
are simple enough !

The goal is of course to create something reusable, instead of everybody
writing their own favorite and incompatible processors. An other goal is to
let non-programmers take advantage of a style sheet language. An other goal
is to keep the language as declarative as possible so if you want to
effeciently re-generate PART of the output again because the source XML
document or XSL style sheet changed you can do this.

No argument here that the current XSL processor is limited. We are working
on it (as I assume a couple of other companies). Does this answer your
question ?

Istvan

> -----Original Message-----
> From:	Sharon Adler [SMTP:sca at eps.inso.com]
> Sent:	Friday, January 30, 1998 7:54 AM
> To:	Michael Kay; xml-dev at ic.ac.uk
> Subject:	Re: First experiences with XSL
> 
> Michael,
> 
> As I write this, the XSL WG is 2/3 through its first official meeting.
> The
> Microsoft code does not represent the "Final" XSL but the srawman of some
> of
> the facilities of XSL.  The lack of diagnostics/limited functionality of a
> partial prototype implementation is not any indication of the
> functionality
> or capability of a style language, nor any final implementation. Of course
> you can accomplish what you wanted in Java.  Any hacker can do anything
> they
> want in code, but what about the rest of the world's humans.
> 
> Please don't use the XSL prototype if it is not suitable for you to play
> around with, but give us a chance to create a workable standard.
> 
> Thank you.
> 
> Sharon Adler
> Co-chair, XSL WG
> 
> 
> 
> 
> At 03:05 PM 1/30/98 -0000, Michael Kay wrote:
> >I've downloaded MSXSL and used it to generate HTML for a couple of
> document
> >types, successfully but with a certain amount of frustration caused by
> (a)
> >lack of diagnostics when I got things wrong, and (b) limited
> functionality.
> >
> >I've now implemented the same thing without XSL: I wrote an MSXML
> >application in Java that does a recursive walk down the document tree and
> >calls a registered "handler" class to process each element type. I added
> a
> >number of helper methods such as isFirstOfType() to allow the handlers to
> >get information about their context more easily.
> >
> >Here is an example of one of the handlers (for the XML element tagged
> >SPEECH):
> >
> >class SPEECHHandler extends HTMLNodeWriter {
> >    public void handleElement(ElemNode e) {
> >        if (e.isFirstOfType())
> >            System.out.println("<HR>");
> >        e.walkChildren();
> >        System.out.println("<BR>");
> >        if (e.isLastOfType())
> >            System.out.println("<HR>");
> >    }
> >}
> >
> >I have to report:
> >- the element handlers looked very similar to the XSL rules
> >- the number of DTD-specific lines of code was identical (106 in each
> case!)
> >- it was far easier to debug
> >- you can do very many things that you can't do in XSL, like sorting the
> >children of a node according to some attribute value, or getting
> information
> >about user preferences from an external database.
> >
> >I have yet to spot any disadvantages. I haven't looked at performance or
> >footprint, but I can't see any intrinsic reason why XSL should be smaller
> or
> >faster. (Currently some of the methods like isLastOfType() are very
> >inefficient due to the limited navigation capabilities in MSXML. I could
> >speed it up if I built my own tree!).
> >
> >Any XSL enthusiasts want to prove me wrong?
> >
> >Regards, Mike Kay
> >
> >
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> >
> 
> 
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