W3C home > Mailing lists > Public > public-i18n-core@w3.org > January to March 2008

Re: case in Selectors API

From: Mark Davis <mark.davis@icu-project.org>
Date: Thu, 7 Feb 2008 09:10:42 -0800
Message-ID: <30b660a20802070910o684a3ef6t20b53f937375280d@mail.gmail.com>
To: "Addison Phillips" <addison@yahoo-inc.com>
Cc: public-i18n-core@w3.org
I agree on both counts.

On Feb 7, 2008 8:29 AM, Addison Phillips <addison@yahoo-inc.com> wrote:

>
> All,
>
> I note that we have another example of case-mapping woes in the
> Selectors API document. This case disturbs me and I think we should
> submit a comment. The document is: http://www.w3.org/TR/selectors-api/
>
> The text in question is:
>
> --
> Note: The case sensitivity of namespace prefixes is effectively
> determined by the implementation of the NSResolver object that is used
> to resolve the namespaces.
>
> Note: In Unicode, caseless matching requires both strings that are being
> compared, to be case folded prior to performing a binary comparison
> [CaseMap]. However, since case folding is not the same as simply
> uppercasing or lowercasing both strings and because the comparison is
> being performed by the NSResolver object implemented by the author, this
> specification cannot require case insensitive namespace prefixes.
> --
>
> My problems with this text are:
>
> 1. It seems to me that the WebAPI is doing implementers a disservice
> here. If they would otherwise have required case-insensitivity except
> for the requirement that implementers of NSResolver understand Unicode
> case folding, then ignorance of Unicode case folding shouldn't be a
> barrier to requiring case-insensitivity. I see no reason why a Spec
> cannot require something if it is both well-documented and necessary,
> which appears to be the case here.
>
> For that matter, it isn't strictly a "Unicode" problem (as implied by
> the above): it is a general problem of case-normalizing text. Namespace
> prefixes are not limited to ASCII, and implementations of Selectors API
> need to deal with that fact.
>
> 2. Case-insensitive mapping is not completely sufficient anyway. No
> mention is made of normalization. If there is something they are not
> going to require but should mention, it would be Unicode normalization
> (see CharMod-Norm). Binary comparison of Unicode strings for character
> equivalence requires this normalization over-and-above case-folding.
>
> Regards,
>
> Addison
>
> --
> Addison Phillips
> Globalization Architect -- Yahoo! Inc.
> Chair -- W3C Internationalization Core WG
>
> Internationalization is an architecture.
> It is not a feature.
>
>


-- 
Mark
Received on Thursday, 7 February 2008 17:11:01 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Wednesday, 1 October 2008 10:18:53 GMT