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Re: Which QName?

From: Chris Lilley <chris@w3.org>
Date: Mon, 18 Aug 2003 15:52:17 +0200
Message-ID: <137174897734.20030818155217@w3.org>
To: "L. David Baron" <dbaron@dbaron.org>
Cc: www-tag@w3.org

On Sunday, August 17, 2003, 7:48:38 PM, L. David Baron wrote:

LDB> On Sunday 2003-08-17 16:56 +0200, Chris Lilley wrote:
>> CSS3 also picks the element rules (for both elements and, it seems,
>> for attributes)
>> http://www.w3.org/TR/2003/WD-css3-syntax-20030813/#defining

LDB> No, the default namespace applies only to elements without an
LDB> explicit namespace in CSS3, and attributes without an explicit
LDB> namespace have no namespace.

Ah, excellent. That is as I would expect.

Its not clear from the text in the specification, however (since I
misunderstood it, as one datapoint).

>> "If the optional namespace prefix is omitted, then the namespace
>> URI is considered to be the default namespace. The default
>> namespace applies only to type selectors that have no explicit
>> namespace prefix declared as described in the Selectors Module
>> [SELECT]. "

LDB> The first sentence here describes how the default namespace is
LDB> defined, not how it is used. The second sentence applies the
LDB> element rules only to elements ("type selectors" could perhaps be
LDB> called "element type selectors"). For attribute selectors (see
LDB> [1]) and attr() values (see a future draft of the values and
LDB> units module), no prefix means no namespace.

Thanks for the clear explanation. I suggest that a similar explanation
be added to the specification itself.

LDB> The syntax draft would probably be clearer if the the second sentence
LDB> you quote stated the element vs. attribute rule in general (to apply to
LDB> any CSS modules that use namespaces) rather than referring to the one
LDB> CSS module that currently uses namespaces with element names.

Yes, I agree that it would.

Now, having satisfactorily dealt with element selectors and attribute
name selectors, there is the third case to consider - selecting on
attribute values.

If I have
  <foo xmlns:n="http:example.org/n" bar="n:toto"/>

how do I write the corresponding selector - would it be

@namespace a url(http:example.org/n);
[bar="a|toto"] { color: blue }

and will that selector also match any of

  <foo xmlns:n="http:example.com/m" bar="n:toto"/>
  <foo xmlns:x="http:example.org/n" bar="x:toto"/>
  <foo bar="n:toto"/>
  <foo bar="toto"/>

without any domain specific knowledge? Hoping the answers are
no,yes,no,no for those four examples.

 Chris                            mailto:chris@w3.org
Received on Monday, 18 August 2003 09:52:22 UTC

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