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

From: Leif Halvard Silli <xn--mlform-iua@xn--mlform-iua.no>
Date: Fri, 23 Oct 2009 12:54:23 +0200
Message-ID: <4AE18B5F.1030801@xn--mlform-iua.no>
To: Tony Ross <tross@microsoft.com>
CC: "public-html@w3.org" <public-html@w3.org>
Tony Ross On 09-10-22 23.22:

> Given some of the comments in this thread, I'd like to step
> back and try to get consensus on the core problem. Specifically
> I want to know whether or not the group feels providing some
> sort of a solution for decentralized extensibility, in
> particular decentralized extensibility of markup, is important.
> 
> 
> In short, should HTML 5 provide an explicit means for others to
> define custom elements and attributes within HTML markup?
> 
> Note that supporting decentralized markup extensibility does
> not necessarily mean you feel XML Namespaces are the
> appropriate solution. Other ideas have been shared and there
> are certainly many possible solutions, each with their own pros
> and cons. For the moment let's put these discussions aside. If
> we cannot agree on the problem, then debating the technical
> details of a potential solution is pointless.

W3C specs have at least two distributed extensibility methods: 
profiles and namespaces.

Namespaces are difficult to separate from the namespace. That's an 
advantage when the intention is to never collapse the extension 
with HTML. And a disadvantage otherwise.

Profiles has had success, both with and with the profile 
attribute/profile URIs. Example: Googles 'nofollow'.  Profiles 
defines semantics for existing HTML features. I think the new 
data-* attribute will be incorporated into profiles. And I think 
that just as profiles will cover data-*="", it could also cover 
<data-myelelement></data-myelement> or <x-myelement></x-myelement> 
(predefined prefixes). It could also cover <myprefix-myelement> 
(profile defined prefixes).

I disagree with Maciej in that namespaces are easier to 
incorporate for attributes than for elements. Imagine that Google 
had introduced "google:nofollow" instead ...

Prefixes are today linked to namespaces, only. I think it could be 
possible to have prefix solution that was linked to profiles as 
well. The difference would be: namespaces MUST declare namespaces 
and link the prefix to the namespace. While profiles /could/ also 
work without the profile URI in the document, and /could/ work 
without a direct link from the prefix to the profile URI.
-- 
leif halvard silli
Received on Friday, 23 October 2009 10:54:57 UTC

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