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

On Tue, Oct 6, 2009 at 4:33 AM, Julian Reschke <> wrote:
> Jonas Sicking wrote:
>> We already have one simpler thing, which is what HTML uses, where a
>> nodes meaning is derived from its nodeName alone.
>> ...
> Yes, but sometimes simple is too simple.

I don't normally pitch in on these namespace discussions, because they
go in circles.  But I'm really not clear on something here.  What is
the practical advantage of requiring a namespace declaration that
causes "foo:bar" to be treated as "{http://something-or-other}bar",
over just treating "foo:bar" (or for that matter "foo_bar" or
whatever) as an opaque string, as with CSS vendor-specific extensions?
 After reading numerous lengthy arguments over the matter, I can only
think of about two reasons:

1) It prevents inadvertent prefix collisions.

2) It's widely used already.

The risk of prefix collisions (1) seems minimal.  Allowing extensions
to use a global namespace and trusting implementers to not choose
names that are likely to conflict tends to work fairly well.  CSS
vendor extensions are one good example.  HTTP and e-mail X-* headers
(one namespace for all extensions) also haven't caused major problems
in practice.  Problems would only have to arise, anyway, if both the
prefix *and* the tag name (or attribute, etc.) were the same in two
different extensions, *and* someone wanted to use both extensions in
the same document.  This benefit therefore seems minor at best.

(2) might be true in a generic sense, but not in the specific case of
HTML, and particularly not in text/html.  To the contrary, supporting
XML-style namespaces in text/html would apparently cause significant
interoperability problems with existing content.  At best, widespread
use in other standards is a very weak argument from a practical point
of view.

What exactly is too simple about relying only on nodeName?

Received on Tuesday, 6 October 2009 18:47:00 UTC