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Re: [Bug 1753] The sorting process

From: Kenneth Stephen <marvin.the.cynical.robot@gmail.com>
Date: Thu, 28 Jul 2005 17:37:49 -0500
Message-ID: <808d4e7c05072815377737829b@mail.gmail.com>
To: public-qt-comments@w3.org
Cc: bugzilla@wiggum.w3.org

Hi,

    I confess, I'm a bit confused at the definition of the behaviour
of the comparison operators  being implied by this bug and the XPath
spec. In general, determination of the collation sequence of Unicode
data is very complex. See http://www.unicode.org/reports/tr10/ for
details. In particular, I call your attention to
http://www.unicode.org/reports/tr10/#Common_Misperceptions - none of
which seem to be addressed by the XPath spec. My impression from
reading the XPath spec is that comparison order is defined by Unicode
codepoint order - but this is not useful for languages other than
English .

    Am I missing something? Or is it expected that XPath
implementations wiil implement the Unicode collation algorithm under
the covers and that the various options that are possible (for example
ignoring punctuation, or case sensitivity) are going to be
implementation defined?

Thanks,
Kenneth

On 7/28/05, bugzilla@wiggum.w3.org <bugzilla@wiggum.w3.org> wrote:
> 
> http://www.w3.org/Bugs/Public/show_bug.cgi?id=1753
> 
> 
> mike@saxonica.com changed:
> 
>            What    |Removed                     |Added
> ----------------------------------------------------------------------------
>              Status|RESOLVED                    |CLOSED
> 
> 
> 
> 
> ------- Additional Comments From mike@saxonica.com  2005-07-28 21:37 -------
> Change now applied to the editor's draft. The relevant para now reads (changes
> marked at="Y"):
> 
> <p>In general, comparison of two ordinary values is
>  performed according to the rules of the
>  XPath <code>lt</code> operator. <phrase diff="add" at="Y">To ensure a total
> ordering, the same
>  implementation of the
>  <code>lt</code> operator <rfc2119>must</rfc2119> be used for all the
> comparisons: the one that is chosen
>  is the one appropriate to the most specific type to which all the values can be
> converted by subtype substitution
>  and/or type promotion. For example, if the sequence contains both
> <code>xs:decimal</code> and <code>xs:double</code>
>  values, then the values are compared using <code>xs:double</code> comparison,
> even when comparing two
>  <code>xs:decimal</code> values.</phrase>
>  NaN values, for sorting purposes, are considered to be equal to each other,
>  and less than any other numeric value. Special rules
>   also apply to the <code>xs:string</code> type
>   and types derived by restriction from <code>xs:string</code>,
>   as described in the next section.</p>
> 
>
Received on Thursday, 28 July 2005 22:38:33 UTC

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