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Re: [css3-namespace] Empty String Namespaces

From: Boris Zbarsky <bzbarsky@MIT.EDU>
Date: Tue, 22 Apr 2008 10:08:33 -0500
Message-ID: <480DFF71.1010807@mit.edu>
To: Bjoern Hoehrmann <derhoermi@gmx.net>
CC: www-style@w3.org

Bjoern Hoehrmann wrote:
> I think the results need to be either (yes yes no no) because the imple-
> mentation ignored the @namespace declaration, or (yes no yes no) because
> you treat it as indicating no namespace. Perhaps (no no no no) might be
> okay aswell, but there does not seem to be a good reason to allow any of
> these results.

Note that in terms of, say, the DOM selectors API an empty string default 
namespace means there is no default namespace while an empty string namespace 
for a prefix is an error.

Recasting that in terms of @namespace rules, that would mean that

   @namespace "";

has no effect on matching whatsoever, while

   @namespace foo "";

should be an error.  That would correspond to "yes, yes, no, no", right?

In practice, what happens in Gecko right now is that a default namespace of "" 
is used to indicate "no default namespace", so |@namespace ""| in fact does 
absolutely nothing.  But for non-default namespaces we allow a prefix to map to 
the null namespace (hence the "yes" in column 3 in the table).

-Boris
Received on Tuesday, 22 April 2008 15:09:19 GMT

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