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Re: xml:base (was Re: IRI meets RDF meets HTTP redirect)

From: Jeremy Carroll <jjc@hpl.hp.com>
Date: Thu, 19 Apr 2007 09:09:10 +0100
Message-ID: <462723A6.8010708@hpl.hp.com>
To: John Cowan <cowan@ccil.org>
CC: Sandro Hawke <sandro@w3.org>, semantic-web@w3.org, www-international@w3.org

That looks to me like an issue against xml:base.

IRI (which of course wasn't around at the time) says, section 6.2:

    Intermediate software interfaces between IRI-capable components and
    URI-only components MUST map the IRIs per section 3.1, when
    transferring from IRI-capable to URI-only components.  This mapping
    SHOULD be applied as late as possible.  It SHOULD NOT be applied
    between components that are known to be able to handle IRIs.

There is no inherent limit on the [base URI] Infoset property, 
motivating the restriction to URI rather than IRI. It seems to be a 
requirement of a spec (XML Base?) that it be so.


John Cowan wrote:
> Jeremy Carroll scripsit:
>> Sandro Hawke wrote:
>>> Of course, if you *want* the base end with "résumé" you're out of luck,
>>> since XML Base [1] says you can only use a URI.   But at least you've
>>> avoided the dilemma.
>> Yes I like using xml:base as much as possible.
>> (And I think xml:base does allow non-ASCII chars since it tells 
>> applications how to % encode them)
> There are two different questions here: what characters can appear
> in a [base URI] Infoset property, and what characters can appear
> in an xml:base attribute value?
> The [base URI] property of a document, element, or PI is a URI;
> as such, it can only make use of a limited repertoire, a subset
> of ASCII characters.
> The value of an xml:base attribute is not so limited: it can contain
> (almost) arbitrary Unicode, which is %-escaped before being used
> to alter the base URI property of the element on which it appears
> and the element's children.

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Received on Thursday, 19 April 2007 08:09:29 UTC

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