OASIS Mailing List ArchivesView the OASIS mailing list archive below
or browse/search using MarkMail.


Help: OASIS Mailing Lists Help | MarkMail Help

[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index]
RE: [xml-dev] Serialization of XDM - Use cases / Proposal

Some people have been suggesting using a subset of XQuery syntax, others have been saying it would be better to use XML syntax.
It occurs to me one might achieve both objectives at the same time by using a subset of XSLT syntax. That is, we could define the syntax to be a named xsl:template instruction containing a sequence constructor in which only the following are permitted:
(a) An <xsl:sequence> instruction whose select attribute contains a constructor function with a string literal argument, for example <xsl:sequence select="xs:positiveInteger('5')"/>
(b) An empty <xsl:attribute>, <xsl:value-of>, <xsl:comment>, <xsl:processing-instruction> or <xsl:namespace> instruction whose content is constrained to use no non-literal expressions or AVTs.
(c) An <xsl:element> or <xsl:document> instruction whose content is constrained to hold only <xsl:element>, <xsl:attribute>, <xsl:value-of>, <xsl:comment>, <xsl:processing-instruction> or <xsl:namespace> instructions that themselves follow the same rules.
There might be a need to define some additional attributes specific to the serialization format, e.g. to represent IDness.

From: Michael Kay [mailto:mike@saxonica.com]
Sent: 21 September 2009 14:45
To: 'David A. Lee'
Cc: 'Philippe Poulard'; 'Kurt Cagle'; rjelliffe@allette.com.au; xml-dev@lists.xml.org; 'XProc Dev'
Subject: RE: [xml-dev] Serialization of XDM - Use cases / Proposal

Ouch.  If this cant be done in xquery syntax then my goal of de-serializing an XML representation using a XQuery example implementation is out the door.

Here's my best shot ...

   { fn:QName( "U" , "P:N" ) }
   { my:IdType( "S" ) }    (: wont work will it :( :)

Ok I admit I'm totally stumped.  *IS* there a way to re-animate this example using XQuery (or XSLT?)  ?
I have a feeling that my goal of providing a reference implementation in XQuery will be impossible.  Not even sure how to get element type information re-animated.

I think that in XSLT, the following comes close:
<xsl:attribute name="P:N" namespace="U" type="my:IdType" select="'S'"/>
provided that the recipient has a schema (the correct schema) for the global attribute declaration my:IdType. There are problems if the type is anonymous (you might have to construct a variant of the original schema in which all types have names). As for the isID property, it is ALMOST redundant in XDM: it can in nearly all cases be inferred from the type annotation. The exception is where IDness was established as a result of DTD validation rather than schema validation. In that case, yes, I think you're going to have difficulty reconstituting the original sequence using tools written in XSLT or XQuery. (Actually, it hadn't occurred to me this was one of your goals.)
XQuery 1.0 (unlike XSLT 2.0) doesn't allow validation against a type name, and doesn't allow validation of individual attributes. 
Other limitations of using XSLT/XQuery
(a) neither language gives you any way of creating unparsed entities
(b) XQuery 1.0 gives you no way of creating arbitrary namespace nodes

[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index]

News | XML in Industry | Calendar | XML Registry
Marketplace | Resources | MyXML.org | Sponsors | Privacy Statement

Copyright 1993-2007 XML.org. This site is hosted by OASIS