Re: questions about XSLT philosophy: how much is too m

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Subject: Re: questions about XSLT philosophy: how much is too much?
From: Wendell Piez <wapiez@xxxxxxxxxxxxxxxx>
Date: Wed, 19 Mar 2003 12:05:12 -0500

At 09:01 AM 3/19/2003, Jeff wrote:

There are two parts to this. First, there are things that are reasonable uses for XSLT. Some are hard right now, but solutions will be added to XSLT 2.0 -- grouping, regular expressions and date handling are examples. Some other things can be done, but will always be a little difficult. Then again, there are things that XSLT will never do well. Yesterday's thread about converting Cobol (or maybe Cobol Data) to XML probably goes in that category.

Broadly speaking, XSLT is very good at "down-translations" (manipulating information based on explicit markup structures and features), but not so good for "up-translations" (inferring structures and features that are not directly expressed in the markup). Regular expressions and more sophisticated string handling in general, along with the nodeset() function, will take it some way towards the latter. Grouping is a good proof of this rule, as it's an up-translation (though not the most challenging one).

If you want to know why this is, the historical context that Dave C. cited is helpful; the first paragraphs of the XSLT Rec, where its design goals are stated, are also worth contemplating.

A corollary to this principle is that XSLT is at its best when working over XML whose design is well fitted to the task. From well-designed (and well tagged) XML, most everyday applications will be "downhill". Poorly designed XML makes the XSLT hard. (Though only remarked on occasionally, we see this every day on this list.) Ironically, it seems these days that much of the work to which XSLT is being put is really just to mitigate difficulties caused by poor design (to wrestle the XML, that is, through some combination of up- and down- translation, into something more tractable for the next step).

Cheers,
Wendell


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Wendell Piez                            mailto:wapiez@xxxxxxxxxxxxxxxx
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Current Thread

Re: questions about XSLT philosophy: how much is too much?, (continued)
- Jeff Kenton - Wed, 19 Mar 2003 08:58:11 -0500 (EST)
  - Robert P. J. Day - Wed, 19 Mar 2003 10:34:30 -0500 (EST)
    - Jeff Kenton - Wed, 19 Mar 2003 10:52:41 -0500 (EST)
    - David Carlisle - Wed, 19 Mar 2003 10:59:04 -0500 (EST)
  - Wendell Piez - Wed, 19 Mar 2003 12:10:38 -0500 (EST) <=
  - Michael Kay - Wed, 19 Mar 2003 18:59:43 -0500 (EST)
    - Jeni Tennison - Fri, 21 Mar 2003 07:39:38 -0500 (EST)
    - Michael Kay - Fri, 21 Mar 2003 13:07:27 -0500 (EST)
- Wendell Piez - Wed, 19 Mar 2003 12:10:38 -0500 (EST)

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Re: questions about XSLT phil, David Carlisle	Thread	RE: questions about XSLT phil, Michael Kay
RE: include css in xsl, Passin, Tom	Date	Re: questions about XSLT phil, Wendell Piez
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