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Re: ISSUE-24: Proposal for dealing with case-insensitive terms in the XHTML vocabulary

From: Ivan Herman <ivan@w3.org>
Date: Wed, 14 Jul 2010 08:52:15 +0200
Cc: RDFa WG <public-rdfa-wg@w3.org>
Message-Id: <68CCA68C-AA6B-4B47-8693-63766CF49EEC@w3.org>
To: Shane McCarron <shane@aptest.com>
This is the cleanest and most pragmatic solution. +1.

That being said, there is a related issue that we may want to handle together, and this is the issue on default @vocab value. At the moment RDFa Core defines http://www.w3.org/1999/xhtml/vocab# as a default value. What this means is, unless I misunderstand something is that _all_ terms in a, say, @rel get a URI; either using the user defined @vocab or with http://www.w3.org/1999/xhtml/vocab#. Note that this is also valid for, say, an SVG run, which is, sort of strange.

My preferred approach would be:

1. in RDFa Core there is no default @vocab. If a term is used without a valid @vocab, it is not interpreted, an error is raised. Otherwise terms are interpreted with @vocab in a case sensitive manner

2. in RDFa+XHTML (and I presume in RDFa+HTML5) there is a a default @vocab, namely http://www.w3.org/1999/xhtml/vocab# and, if this is the one in effect, then terms are interpreted in a case insensitive way, ie, terms must be mapped on lower case.

Note that this is still more than what we have in RDFa1.0: indeed, RDFa1.0 restricted the accepted terms to those defined in the XHTML standard; whereas here any term can be used. We may want to reinforce that in #2 above, but I am not sure it is necessary.


On Jul 14, 2010, at 24:01 , Shane McCarron wrote:

> In general, I feel that terms should always be treated as case sensitive.  However, I agree that for backward compatibility reasons, the terms defined in *OUR* XHTML vocabulary, as extended by terms that are defined in HTML5, should be mapped to lower case when processing.
> I do not think this is an RDFa Core issue.  Rather, I think that in RDFa Core we should say:
>   TERMs, CURIEs, and URIs are all case sensitive.  Host Languages may
>   place further processing requirements on TERMs (e.g., requiring they
>   be mapped to lower case).
> In XHTML+RDFa 1.1 we should say:
>   When referencing TERMs in the vocabulary at
>   http://www.w3.org/1999/xhtml/vocab, TERMs must be mapped to lower case.
> I imagine we would need to say something similar in HTML+RDFa.
> -- 
> Shane P. McCarron                          Phone: +1 763 786-8160 x120
> Managing Director                            Fax: +1 763 786-8180
> ApTest Minnesota                            Inet: shane@aptest.com

Ivan Herman, W3C Semantic Web Activity Lead
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Received on Wednesday, 14 July 2010 06:52:19 UTC

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