RE: [xsl] Re: Overlapping structures
Subject: RE: [xsl] Re: Overlapping structures|
From: Wendell Piez <wapiez@xxxxxxxxxxxxxxxx>
Date: Wed, 10 Oct 2001 12:14:14 -0400
At 06:51 AM 10/10/01, Mike wrote:
> <a>I said <z.start/>I will watch my ways</a>
> <a><x/>and keep my tongue from sin<z.end/></a>
> Can somebody give an example to justify why such an ugly
> thing might be necessary in
> the first place?
Because not all information is hierarchical. In particular, with text there
are often several concurrent (overlapping) hierarchies. The most obvious is
the section structure versus the pagination structure. But it's easy to find
other examples: in Shakespeare, the boundaries of "speeches" (defined by who
is speaking) overlap with the boundaries of "lines" (defined by the metre of
Or, in narrative poetry, metrical lines vs. verse paragraphs (which
sometimes divide in the middle of lines), vs. dialogue (which can overlap
lines and verse paragraphs, while nesting in its own right), vs. rhetorical
events such as epic similes, etc. etc. Not to mention pagination in
different editions, textual variants and so forth.
(I know one reader of this list who is using XSLT to generate SVG
depictions of the page collations, and forme works, of various printed
editions of given historical texts. Your application of XML/XSLT is
probably as arcane to him, as his is to you.)
Someone had it right who remarked that these are applications in which
markup is used to describe or trace phenomena already observable in extant
data (texts, artifacts), as opposed to creating new data with new
structures already optimized for particular functions. In the latter case,
you can sometimes engineer the multiple hierarchies away, or more commonly,
simply decide they're not important enough to bother with. In the former --
an important use case for markup languages -- to engineer them away is to
fail at your primary goal.
As for ugly, yea verily, and if anyone can come up with a beautiful
notation cum data model that describes multiple hierarchies and supports
XMLish "synchronous" processing (by which I mean something like "random
access" to a structured data set) ... there are plenty of us who want to
hear about it!
And if you mark up a document with change markings, the
start/end of changed sections bear no relationship to the logical structure
of the text.
Yup. Or what one might call a "vexed relation", since what is changed is
often precisely that logical structure. Even worse.
Wendell Piez mailto:wapiez@xxxxxxxxxxxxxxxx
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