- From: Julian Reschke <julian.reschke@gmx.de>
- Date: Sat, 23 May 2009 20:05:57 +0200
- To: Philip Taylor <pjt47@cam.ac.uk>
- CC: Sam Ruby <rubys@intertwingly.net>, Shane McCarron <shane@aptest.com>, RDFa Community <public-rdfa@w3.org>, "public-rdf-in-xhtml-tf.w3.org" <public-rdf-in-xhtml-tf@w3.org>, HTML WG <public-html@w3.org>
Philip Taylor wrote: > ... > Hmm, maybe a better example of what I intended is: > > <div xmlns:t="test1:"> > <div xmlns:T="test2:"> > <span property="t:x T:y">Test</span> > </div> > </div> > > which is well-formed XML and has a clear definition in RDFa-in-XHTML, > but the defined behaviour is impossible to reproduce in text/html > (because xmlns:t and xmlns:T (and XMLNS:T) are parsed identically by an > HTML parser and there's no way to distinguish them afterwards). > > RDFa-in-text/html could: > > * Assume attributes are all treated as lowercase (breaking <div > xmlns:T="..." property="T:..."> which works in XHTML); > > * Say CURIEs (in both XHTML and HTML) match prefixes case-insensitively > (breaking compatibility with current implementations); > > * Change text/html parsing to preserve attribute case (breaking > compatibility with current parsers); > > * Use some other prefix-binding mechanism (in both XHTML in HTML) like > prefix="t=... T=..." instead of xmlns:t="..." (breaking current > implementations and deployed content, but avoiding the mess of parsing > differences between XHTML and HTML). > > I can't think of any other solutions, so something is going to break no > matter what is chosen. It's clear that if RDFa is to be used with prefix declarations done with xmlns, then mixing uppercase and lowercase declarations is not going to work. I think restricting prefixes to be lower-case (insert proper Unicode terminology here) would be acceptable; it's easy to live with, and avoids introducing yet another prefix declaration mechanism. BR, Julian
Received on Saturday, 23 May 2009 18:06:49 UTC