[
Lists Home |
Date Index |
Thread Index
]
At 12:12 PM -0500 3/4/02, Simon St.Laurent wrote:
>It is both an element and a "syntax for general purpose inclusion....
>merging a number of XML information sets into a single composite
>Infoset."
>
>XInclude explicitly avoids definining relationships with XML Schemas and
>DTDs, but this kind of non-definition feels eerily to me like Namespaces
>in XML, which is concise but has left us debating for the last few
>years.
The algorithm for DTD validation is defined by XML 1.0. XInclude
doesn't change it. Give me an XML document and a validating parser,
and I can tell you whether or not that document is valid. The
presence or absence of XInclude elements is irrelevant to this
determination. If they're present, the DTD just has to declare them
like any other elements in order for them to be valid. Schemas are
similar, except it's even easier because you don't necessarily have
to serialize the infoset before applying the validation algorithm.
Canonicalization is similar, except the algorithm is even more
clearly defined. Give me an XML document. I'll apply the algorithm to
it and return its canonical form. This algorithm assigns no special
semantics to any elements including xinclude:include elements.
XInclude does not change the definition of canonicalization.
Most importantly, XInclude does not change the definition of an XML
document. A process such as canonicalization which is designed to
operate on arbitrary XML documents does not change its behavior when
the document happens to contain xinclude:include elements.
> Documents may now be read as describing multiple infosets - one
>including XInclude elements as elements, one representing the result of
>complete infoset merging, and various infosets representing possible
>failure states.
>
No, that's the confusion. A single XML document describes a single
infoset. A single document does not describe multiple infosets.
Performing inclusion on a document generates a new infoset, which if
you choose can be serialized into a new document. (Actually there are
a few holes in the spec here, but they're not relevant to the current
discussion.) This is not, however, the infoset that was described by
any of the original documents (again, except in the trivially
uninteresting case where the original document did not contain any
xinclude:include elements).
Documents may not be read as describing multiple infosets, at least
not if you wish to be conformant to the various W3C specs. You can
use XInclusion to produce new infosets from old infosets, but then
you can do this with XSLT, SAX, or DOM, so this is nothing new.
--
+-----------------------+------------------------+-------------------+
| Elliotte Rusty Harold | elharo@metalab.unc.edu | Writer/Programmer |
+-----------------------+------------------------+-------------------+
| The XML Bible, 2nd Edition (Hungry Minds, 2001) |
| http://www.cafeconleche.org/books/bible2/ |
| http://www.amazon.com/exec/obidos/ISBN=0764547607/cafeaulaitA/ |
+----------------------------------+---------------------------------+
| Read Cafe au Lait for Java News: http://www.cafeaulait.org/ |
| Read Cafe con Leche for XML News: http://www.cafeconleche.org/ |
+----------------------------------+---------------------------------+
|
