Re: [xsl] How Can I Reference previous XML in Subsequent Iterations?

[Abel Braaksma <abel.online@xxxxxxxxx>]

Chris M. wrote:
> Wow. Thanks for all the help!
>
> I'll have to digest it a bit later on, but this sure beats the sound 
> of crickets chirping I've had on other forums.
>
> Someone posted in another thread that "XSLT is dead," but I think that 
> it is really just not being explained/evangelized well enough (which 
> is what is making XML in general such a tough sell). 

Hmm, for about eight years I have been working with XML and related 
technologies. There are currently very few tools around there, 
especially in the enterprise market, that ignore XML. With XSLT, more 
and more enterprise products and frameworks (BEA, SAP, StreamServe, 
Cocoon, MS BizTalk, .NET, Java), end-user products (MS Word, OpenOffice, 
Adobe) and browsers (IE, Firefox, Mozilla, Opera, Safari) all offer some 
kind of XSLT support.

With XSLT 2.0, the story is a bit different, but it's only an official 
recommendation since January 2007, so you should give it a couple of 
more months/years.

> People like me, who have a solid background in computer science, 
> aren't very common. I can hunt down information and sort through 
> chaff, but your average Web designer can't do this as easily. It can 
> take them years to build up a reference schema, so to speak, and 
> XML/XSL is presented as a completely new "paradigm," with no 
> connection to their known schema. As has been pointed out, the 
> thinking needs to be different. XSLT starts with the assumption that 
> the learner has a fairly solid understanding of XML first (especially 
> namespaces -Excedrin Headache #2), which is a brick wall barrier to 
> many people who would otherwise enthusiastically embrace the 
> advantages of XSLT.
>
> I'm no XSLT expert, but I have already developed a site that does 
> automatic transforms for WML 1, WML 2 or XHTML, depending upon the 
> user agent. When I show this to people who do regular Web sites, their 
> jaws drop. They would LOVE to be able to do it. However, when I start 
> explaining how I do it, they get all googly-eyed and start snoring.
>
> The problem is to bring XML to the Proletariat. Not sure how this is 
> best handled. W3schools has a fairly good tutorial, but even that is 
> fairly light on the "big picture."

Interesting. I don't believe that XSLT, nor XML is catered for the 
'Proletariat'. I hope it will remain in the area of professionals for a 
long time to come (unfortunately, this is not true anymore for several 
years now, considering the garbage coming out from XML-esque programs 
and tools that are not even close to being well-formed etc, let alone 
the XML-like programming in PHP, Perl etc, were string-concatenation and 
string-comparison are the main tools for working with XML, emphasizing 
that too many non-pros are now transforming the XML Lake into XML Moors).

It is true that it helps if you understand XML quite well before 
tackling languages and tools that work with XML. But XML, though easy to 
learn and use, can be harder to master thoroughly (years, even for 
professionals). Putting XML+Namespaces, XML Schema, DOM, the XML Infoset 
model and (yes we still need it) DTD to the picture and people get 
easily lost. You can do without them, but if you want to master XSLT, 
it'll help you a great deal if you have an above-average understanding 
of these techniques.

No, I don't see a world where some HTML designer starts out with using 
XSLT. XSLT is an easy to learn language if you get the right guide (just 
hire Michael Kay, Wendell Piez, Jeni Tennison, David Carlisle, M David 
Peterson, Andrew Welch or Dimitri Novatchev (not sure they are all 
available, but I consider there teaching skills and topic understanding 
very high, sorry if I forgot about someone)), but it is about *data* 
transformation, which is much more abstract (and boring) than visual 
display (for which you can use HTML, XSL-FO, SVG or just Adobe 
Photoshop). A graphic designer should do what (s)he is best at: design 
graphically.

XSLT is for the same kind of people that nowadays connect disparate data 
systems, exchange data, transform from format X to format Y, setup data 
transformation frameworks and, possibly, create some master stylesheets 
and let designers provide their (easy and restricted!) stylesheets which 
run together. XSLT is a bit like the game Go. It is very simple and easy 
at start, but the further you get, you find that it is extremely 
powerful and it will take you a long time to find the depth of the 
rabbit hole.

Cheers,
-- Abel Braaksma