Re: [ubl-dev] XPath expressions in UBL / Signatures

["G. Ken Holman" <gkholman@CraneSoftwrights.com>]

Yes, what you have is certainly unambiguous.

It could also be seen as redundant.  The namespace declarations in 
scope also happen to declare the prefixes you've declared in the 
XQuery prologue.

However, I think you have convinced me that in fact explicit 
prefix/namespace associations are mandatory as information (not as 
syntax), and I likely wouldn't have come to this conclusion without 
seeing your example.

The way to see this as not redundant is our premise all along in UBL 
(and in XML) that instance prefixes are arbitrary.  As soon as I put 
a requirement on in-scope namespace declarations, I've just broken 
that allowance.

If I process a UBL document, and in that process I munge the 
namespace prefixes into other prefixes that are still valid prefixes, 
all of a sudden the XPath field value is rendered irresolvable 
because the in-scope namespace declarations are no longer in 
alignment with the data content.

But not in your example.  Your example is very helpful.

However, for expression languages that do not include explicit 
namespace declarations (e.g. XPath and not the XQuery superset), one 
would need a repeating ASBIE of a prefix/namespace pair ABIE, with 
which a downstream process can unambiguously interpret the prefixes 
used in the given expression.

And it means the existing simple XPath expression BBIE has a built-in 
assumption about in-scope namespace bindings.

But ... this is all speculation until someone identifies a need with 
an official comment to the UBL committee for 
consideration.  According to the committee meeting minutes, public 
review draft 2 should be out soon ... a good opportunity to submit comments.

Thanks, Steve.

. . . . . . . . . . Ken

At 2011-05-15 15:01 +0100, Stephen D Green wrote:
>This would give ( in some hypothetical future UBL version 2.x - not
>in existing UBL ) a way to include an adequately declared XPath 2.0
>in a UBL document:
>
>
><cac:XmlExpression>
><cbc:XmlExpressionLanguageID><http://www.w3.org/TR/xquery/>http://www.w3.org/TR/xquery/</cbc:XmlExpressionLanguageID>
><cbc:XmlExpressionLanguageVersionID>1.0</cbc:XmlExpressionLanguageVersionID>
><cbc:XmlExpressionString>declare default element namespace 
>"urn:oasis:names:specification:ubl:schema:xsd:Invoice-2"; declare 
>namespace cbc = 
>"urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2"; 
>(/Invoice/cbc:ID)[1]</cbc:XmlExpressionString>
></cac:XmlExpression>
>
>
>However, since XQuery itself allows the version information to be 
>declared in the expression itself, maybe the 
>XmlExpressionLanguageVersionID could be optional and that version 
>information included in the XQuery expession:
>
>
><cac:XmlExpression>
><cbc:XmlExpressionLanguageID><http://www.w3.org/TR/xquery/>http://www.w3.org/TR/xquery/</cbc:XmlExpressionLanguageID>
><cbc:XmlExpressionString>xquery version "1.0"; declare default 
>element namespace 
>"urn:oasis:names:specification:ubl:schema:xsd:Invoice-2"; declare 
>namespace cbc = 
>"urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2"; 
>(/Invoice/cbc:ID)[1]</cbc:XmlExpressionString>
></cac:XmlExpression>
>
>
>Best regards
>
>Steve


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