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RE: on "ORDER with IRIs" comment and user-selectable collation units

From: Howard Katz <howardk@fatdog.com>
Date: Mon, 8 Aug 2005 11:13:38 -0700
Message-Id: <200508081813.j78IDfqW001975@pyramid-01.kattare.com>
To: <andy.seaborne@hp.com>, "'Dan Connolly'" <connolly@w3.org>
Cc: "'RDF Data Access Working Group'" <public-rdf-dawg@w3.org>

 

 > -----Original Message-----
 > From: public-rdf-dawg-request@w3.org 
 > [mailto:public-rdf-dawg-request@w3.org] On Behalf Of Seaborne, Andy
 > Sent: Monday, August 08, 2005 10:36 AM
 > To: Dan Connolly
 > Cc: RDF Data Access Working Group
 > Subject: Re: on "ORDER with IRIs" comment and 
 > user-selectable collation units
 > 
 > 
 > 
 > 
 > Dan Connolly wrote:
 > > Hoehrmann writes, 'section 10.1
 > > notes "IRIs are ordered by comparing the character strings 
 > making up 
 > > each IRI" it's however not clear how character strings are 
 > compared'
 > >  -- 
 > > 
 > http://lists.w3.org/Archives/Public/public-rdf-dawg-comments/
 > 2005Jul/0
 > > 038
 > > 
 > > I would have thought it's obvious that we mean lexical order by 
 > > unicode code-point. I thought there must be some anchor in 
 > [CHARMOD] 
 > > for that, but while I was looking, I found...
 > 
 > I belive the problem stems, at least in part, from the fact 
 > that rq23 does not define "<"  on xsd;strings.  It defines 
 > it on (numeric,numeric) and (dateTime,dateTime).  If rq23 
 > extended "<" to include (xsd:string,xsd:string) then the 
 > text above could refer to that otherwise it will have to 
 > explicitly state that the character strings are compared by 
 > codepoint sequence.
 > 
 > This also applies for sorting by a variable that is always 
 > an xsd:string, so I'd like to see "<" defined by 
 > (xsd:string,xsd:string).
 > 
 > > 
 > > 
 > > C066  [S]  [I]  Software that allows users to sort or search text 
 > > SHOULD allow the user to select alternative rules for 
 > collation units 
 > > and ordering.
 > > 
 > >  -- 
 > http://www.w3.org/TR/2005/REC-charmod-20050215/#sec-CollationUnits
 > 
 > Do we allow explicit calls to fn:compare()?
 >    http://www.w3.org/TR/xpath-functions/#func-compare
 > which does allow various collations.
 >    http://www.w3.org/TR/xpath-functions/#collations
 > 
 > One comment - xpath-functions seems to allow the default 
 > collation to be set externally to the query.  For 
 > interoperability between client and server, can we state 
 > that the default default collation (that used if there is no other
 > information) is by codepoint?

Sure, why not? That's exactly what the XQuery/Xpath F&O doc [1] states:

"The XQuery/XPath static context includes a provision for a default
collation that can be used for string comparisons and ordering operations.
See the description of the static context in Section 2.1.1 Static ContextXP.
If the default collation is not specified by the user or the system, the
default collation is the Unicode code point collation
(http://www.w3.org/2005/04/xpath-functions/collation/codepoint)."

Howard

[1] http://www.w3.org/TR/xpath-functions/#collations
Received on Monday, 8 August 2005 18:13:49 GMT

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