Item description data in XML (XML)
ldodds at INGENTA.COM
Mon Nov 29 17:26:20 CET 1999
> Don suggested to encode the data element like:
> <leaf shape="obovate" length_mm="31"/>
> (NB: Please read the hardcoded namespace as an example only, see
> my separate "(GEN) Schema independence" post)
> As far as I understand XML, these attributes would be automatically
> hidden from view, which is fine for the markup purpose. However, I
> would prefer a coding method, which would allow comprehensive use of
> XML for the data definition part as well.
I'm not sure what you mean by 'hidden from view' - do you mean when
rendered into a web browser? If so then I'd be wary about making assumptions
as to what type of applications will be processing the markup. Using
the DOM and/or SAX programming APIs I can get direct access to the
attributes of an element and then process them just as I could any
My XML based application may not render the data at all - it might
just use the data to perform some other functionality - lets not
get too fixed up on the visual representation.
> Probably a stylesheet could determine whether only the free text with
> hidden markup is visible, only the data, or both?
> Any ideas, perhaps any technical suggestions, how to achieve that?
Again, apologies if I mis-read your intent...
An XSL stylesheet defines how to render an XML document into 'Formatting
Objects' which are then handled by the renderer as it requires. One
such renderer may be a web browser. Another might be a PDF document
XSL is based on XSLT which is a means of taking an XML document
and producing another document from it (not necessarily XML).
XSLT currently supports three output methods - XML, plain-text
and HTML. XSLT is commonly used to take XML and render it into
HTML for the web - useful because there is limited support
for XML in browsers. IE5.0 for example has an XSL implementation
which is out of date, and Netscape lacks one at all.
Now to go back to your question - how the XML is handled depends
on the application. One application might be generating plain-text
descriptions of the data, or indeed backwards compatible
files (I give an XSLT stylesheet for generating DELTA character
files from XDELTA files at : http://www.bath.ac.uk/~ccslrd/delta/)
Another application might render the XML directly into a browser,
and might use another suitable stylesheet. So the first thing
to note is that your stylesheet is going to be determined
by what kind of output you're expecting - I wouldn't expect
a 'default' stylesheet at all. Instead there will be
different stylesheets for different contexts (web browser,
PDF, plain-text, etc, etc).
Secondly I might not be generating anything visible at all. I can
well imagine an application that will take an XML document and
from the data within produce (say) a taxonomic tree or tress of that
data. Here I wouldn't use a stylesheet, I'd simply process the
Let me know if I can provide any more info on the above.
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