W3C home > Mailing lists > Public > public-html@w3.org > February 2009

RE: ISSUE-4: Versioning, namespace URIs and MIME types

From: Larry Masinter <masinter@adobe.com>
Date: Tue, 17 Feb 2009 15:40:39 -0800
To: Ian Hickson <ian@hixie.ch>
CC: HTML WG <public-html@w3.org>
Message-ID: <8B62A039C620904E92F1233570534C9B0118C8659290@nambx04.corp.adobe.com>
I think this may be relevant to the versioning issue; the question is
the role of scripting and DOM APIs on the issue of versioning, whether
two versions of the same language or two different languages
(and, for that matter, whether or not the languages share the
same nominal namespace.)

> DOM APIs do not have a concept of a pre-existing document. You can start 
> from a DOMImplementation object and then create a Document without ever 
> hitting the network or seeing any serialisation of any kind.

DOM APIs do not materialize by "spontaneous generation" 
http://en.wikipedia.org/wiki/Spontaneous_generation 
but come from somewhere. 

Implementations that only implement one language or version should
select the language or version they implement, and only execute 
DOM APIs because the DOM API calls appeared in some document in
the language they implemented. 

There is not any issue in a single-language implementation, because 
the context language is implicit. "If you get here, you must have
passed through the selection gate gate."

Implementations that support more than one language or 
incompatible version need to, along with the code that can generate 
or access a DOM, remember the language or version 
associated with the code.

(I believe browser implementers might think of this as a 'mode'
such as 'standards compliant mode' but it's really a language
selection rather than an executional mode.)  

You might think this is a significant implementation overhead, but
we've heard assertions that no one is actually planning on implementing
a dual-language viewer, so the cost of implementation might not
be an issue in practice; secondly, the cost of remembering language
indication along with parsed code doesn't seem to be a significant
additional complexity from the difficulty of supporting two languages
in the first place.

I'm not sure there's a use case for a script embedded in
one language or version to generate a document in another
language or incompatible version.  Is there?

Larry
-- 
http://larry.masinter.net
Received on Tuesday, 17 February 2009 23:45:51 GMT

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