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RE: XQuery 1.0 and XPath 2.0 Functions and Operators: http://www.w3.org/2005/xpath-functions/collation/codepoint

From: Michael Kay <mike@saxonica.com>
Date: Tue, 15 Sep 2009 15:10:43 +0100
To: "'Patrick Durusau'" <patrick@durusau.net>, <public-qt-comments@w3.org>
Message-ID: <DBCC3CED6F8E4B318B157186DB5E071F@Sealion>
> 
> Is "Unicode code point collation *defined* in the 
> XPath/XQuery/XSLT/etc. 
> family of standards or it is simply *named*?
> (If it is defined, a hint as to where to find that definition would be
> appreciated.)

I believe you are correct: the specifications contain no formal definition
of this collation.
> 
> I would suspect that defining it would involve at a minimum 
> specifying some default Unicode normalization as well as what 
> happens after normalization.

It is not intended that this collation should perform any normalization. The
definition is essentially as follows: let X be the sequence of integer
codepoints representing the string x, and let Y be the sequence of integer
codepoints representing the string y. Then the integers of these two
sequences are compared pairwise until a pair is found that differ or until
one or both sequences are exhausted. If a pair is found that differ, then
the lesser of the strings is the one that contains the lesser integer in
this position; if both sequences are exhausted then the strings are equal;
if only one sequence is exhausted then the lesser string is the one whose
codepoint sequence is exhausted.
> 
> PS: If this is the wrong list, please suggest the correct 
> one. This seemed to me to be more of a question about the 
> standard per se than about XQuery or XPath, although the 
> answer would have an impact on both.
> 

I have raised the problem on your behalf at

http://www.w3.org/Bugs/Public/show_bug.cgi?id=7630

If you want to participate in the discussion or to be notified of progress
on its resolution, please add yourself to the cc list for the bug.

Michael Kay
(personal response)
Received on Tuesday, 15 September 2009 14:11:23 UTC

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