CDATA by any other name... (was The raw and the cooked)
cowan at locke.ccil.org
Wed Nov 4 17:00:00 GMT 1998
Paul Prescod wrote:
> XML DTDs are in the business of constraining people to the data models and
> data that the software is expecting/can deal with. I don't see any big
> difference between saying: "This content must be restricted to this set of
> characters" and "this content must be a NMTOKEN or base-64 encoded."
Put that way, I suppose you are right. As I said before, this could and
should be handled as a special case of "The character data of this
element must conform to the following regular expression."
> Nevertheless, this is clearly a schema problem and CDATA sections seem to
> me to be a really bad tool for enforcing this distinction.
Particularly because it would mean that the charset of an XML document
would become part of its schema: a document in US-ASCII can have
only ASCII in its CDATA sections, but if it were transcoded to
ShiftJIS, then it could have any JIS X 208 character in the
So this means that transcoding arbitrary XML documents *requires*
parsing them, because if you are reducing the repertoire, you may need
to break up CDATA sections, and you cannot (?) recognize a
CDATA section reliably without parsing. (In particular, what
looks like a CDATA section start/end could appear as an attribute
value, PI data, or comment.) An interesting side effect!
John Cowan http://www.ccil.org/~cowan cowan at ccil.org
You tollerday donsk? N. You tolkatiff scowegian? Nn.
You spigotty anglease? Nnn. You phonio saxo? Nnnn.
Clear all so! 'Tis a Jute.... (Finnegans Wake 16.5)
xml-dev: A list for W3C XML Developers. To post, mailto:xml-dev at ic.ac.uk
Archived as: http://www.lists.ic.ac.uk/hypermail/xml-dev/
To (un)subscribe, mailto:majordomo at ic.ac.uk the following message;
To subscribe to the digests, mailto:majordomo at ic.ac.uk the following message;
List coordinator, Henry Rzepa (mailto:rzepa at ic.ac.uk)
More information about the Xml-dev