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Re: ISSUE-41/ACTION-97 decentralized-extensibility

From: Julian Reschke <julian.reschke@gmx.de>
Date: Thu, 01 Oct 2009 11:13:54 +0200
Message-ID: <4AC472D2.6090004@gmx.de>
To: Jonas Sicking <jonas@sicking.cc>
CC: Adrian Bateman <adrianba@microsoft.com>, HTML WG <public-html@w3.org>, Tony Ross <tross@microsoft.com>, Sam Ruby <rubys@intertwingly.net>
Jonas Sicking wrote:
> On Wed, Sep 30, 2009 at 11:26 PM, Julian Reschke <julian.reschke@gmx.de> wrote:
>> Jonas Sicking wrote:
>>> ...
>>> I'm not actually a big fan of this proposal. Experience with
>>> namespaces in XML has showed (at least to me) that namespaces are too
>>> complex for authors to understand. The most recent example of this was
>>> the discussion on RDFa+HTML where it was clear that even the experts
>>> that developed RDFa thought of nodes as receiving their meaning from
>>> their nodeName rather than from their localName+namespaceURI.
>>> ...
>> Pointer?
> 
> This is one example:
> 
> http://lists.w3.org/Archives/Public/public-html/2009Sep/0923.html
> 
> But really, the whole thread is filled with missunderstandings about
> how namespaced nodes in the DOM work.

Yes, I agree that the way namespaces work in DOM, and the way L1 and L2 
differ, are confusing. That's a problem of DOM though, not of XML 
namespaces in general.

Also, dispatching on nodeName is entirely sane if you need to be able to 
run with DOM Level 1.

> ...
>> Not sure what you're comparing here. As far as I can tell, there is no
>> proposal here to use prefixes (a la qname or curie) in content.
> 
> Are you asking just in relation to the second of my paragraphs above?
> I don't understand the question if it's in relation to the first one
> as well.
> 
> Assuming it applies to the second:
> 
> One of the problems with namespacing a'la XML Namespaces is that an
> objects identifing name isn't a single string, it's a tuple. Everyone
> has to lug around two separate values, localName and namespaceURI.

No, that's an API problem. There are other APIs that use expanded names 
as identifiers.

> (Many times implementations have to lug around three values,
> localName, namespaceURI, and prefix).
> 
> RDF has not chosen to use this. Instead it concatenates the expanded
> prefix together with the localName-esq value in order to form a single
> string. Each part of an RDF triplet, subject, predicate and object, is
> identified by a single string (though in the case of object there's
> additionally a datatype). The triplet does not consist of 3 string
> tuples.
> ...

But that's because RDFa is a notation for RDF, which uses URIs, not 
(namespace,localname) tuples.

> ...
> However the proposal from microsoft still uses tuples of strings to
> identify element and attribute names.
> ...

There's a well-understood way to map these tuples to simple strings, and 
back, so again, this is only an API problem.

BR, Julian
Received on Thursday, 1 October 2009 09:14:33 UTC

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