[XSL-LIST Mailing List Archive Home] [By Thread] [By Date]

cdata was: XSL and HTML

---

---

> <xsl:cdata> tag, there is an obvious need for this

What would <xsl:cdata> mean?

This is a real question, as I don't currently see what it could mean
(despite the fact that you mention it is implemented in some systems:-).

My understanding is that the XSL stylesheet is itself parsed as an XML
document, and takes as input a parsed XML document, and produces as
output an XML document tree.

It is the tree that is effectively the end result of the XSL process.
If the tree is being written to a file then it has to be serialised
in some way using the concrete XML syntax such that a parser could
re-create the tree, but there is no way just from the characters
in the leaves of the tree to control that serialisation.

When parsing,  &amp; and <![CDATA[&]> both produce the same thing, namely
the ampersand character. It thus surely follows that if an ampersand
character is entered into the result tree, which is then to be written
to a file, one of these must be written, but you can't control which
from _within_ the tree.

Well of course you can hypothesise extra information in addition to
characters that gets stored in the internal tree. (As happens in the DOM
where CDATA sections are distinguished).

But that would be a big change (and not at all clearly a change for the
better) but in any case it would seem to be a change in the basic data
model on which XSL is working, it isn't just a small request to add one
harmless extra tag.

I am not arguing (here) that there should not be such functions, just
arguing that adding them is a bigger step than has been implied in some
recent messages.

I would have argued that the same was true of comments, that comments
parse to nothing, and so there was no way to output a comment to the
result, but that battle appears to have been lost. Comments are no
longer really comments in XML, they do form nodes in the internal tree
structure, so the functionality of a comment is effectively lost (you
could have used a comment element if you wanted a node, but still, it
appears to be done now).


David


 XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list

---