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RE: [CSS21] uri()

From: Addison Phillips <addison.phillips@quest.com>
Date: Tue, 3 May 2005 14:42:43 -0700
Message-ID: <634978A7DF025A40BFEF33EB191E13BC0B3907E7@irvmbxw01.quest.com>
To: "Ian Hickson" <ian@hixie.ch>, "Richard Ishida" <ishida@w3.org>
Cc: <www-style@w3.org>, <public-i18n-core@w3.org>

What follows is a personal response.

I believe that you are confusing two different issues here.

IDN imposes particular restrictions on what can be registered in a domain name (and what user-agents must do when requesting content from a non-ASCII domain name in order to encode the characters for DNS).

IRI, by contrast, describes how to use non-ASCII characters in URIs. While domain names are certainly a part of a URI, their handling in IRI has nothing to do with Stringprep or Punycode. Implementations of one are not coupled to implementations of the other necessarily.

URIs are quite important in CSS. I would strongly suggest that IRI would make sense to include there so that implementations will begin to track to this standard mechanism for representing non-ASCII URIs. Whether particular implementations support IDN when actually retrieving content is a separate matter.

Items 1b and 1c in Section 3 of IRI basically say that URIs should use the UTF-8 encoding for percent escaping non-ASCII characters (making them reliable, whereas today they might NOT be encoded using UTF-8, causing interoperability woes). This requires no special knowledge of Unicode, merely conversion between the native encoding and Unicode (when a native, legacy encoding is used for the stylesheet). Since the character set for HTML and XML is Unicode and since Unicode holds at least a special place in CSS, this doesn't strike me as an insuperable burden. 

I do recognize that strict adoption of IRI would have a certain impact on CSS. In particular, it might require a close look at the formal grammar in Appendix G of CSS 2.1. But I think we should really discuss this before you reject making a normative reference to IRI.

Regards,

Addison

Addison P. Phillips
Globalization Architect, Quest Software
Chair, W3C Internationalization Core Working Group

Internationalization is not a feature.
It is an architecture. 

> -----Original Message-----
> From: public-i18n-core-request@w3.org [mailto:public-i18n-core-
> request@w3.org] On Behalf Of Ian Hickson
> Sent: 2005?5?3? 10:07
> To: Richard Ishida
> Cc: www-style@w3.org; public-i18n-core@w3.org
> Subject: Re: [CSS21] uri()
> 
> 
> On Tue, 3 May 2005, Richard Ishida wrote:
> >
> > Note that http://www.ietf.org/rfc/rfc3986 now obsoletes rfc 1808 and
> updates
> > rfc 1738.
> 
> I have added this to our issues list, thanks.
> 
> 
> > Also, RFC 3987 Internationalized Resource Identifiers (IRIs) is now an
> IETF
> > Proposed Standard, and references rfc 3986.
> 
> We considered updating CSS2.1 to use IRIs. However, there was some concern
> that the requirements in RFC 3987 were unimplementable. In particular, the
> difference between steps 1b and 1c in section 3.1 imply behaviour that
> would be hard to specify in terms of the CSS model. There was also a
> concern that the difference between RFC 3987 5.3.2.2:2 and RFC 3491 2 (qv.
> RFC 3454 B.2) would require implements to include excessive amounts of the
> Unicode database in IDN/IRI-aware CSS processors. Therefore, until the
> working group has more implementation experience, IRI processing
> requirements have not been added to CSS.
> 
> --
> Ian Hickson               U+1047E                )\._.,--....,'``.    fL
> http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
> Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'
Received on Tuesday, 3 May 2005 21:42:55 GMT

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