W3C home > Mailing lists > Public > public-xml-id@w3.org > January 2005

Re: 4. ID assignment and the empty string

From: Ian Hickson <ian@hixie.ch>
Date: Thu, 27 Jan 2005 10:58:20 +0000 (UTC)
To: Norman Walsh <Norman.Walsh@Sun.COM>
Cc: public-xml-id@w3.org
Message-ID: <Pine.LNX.4.61.0501271044190.12500@dhalsim.dreamhost.com>

On Wed, 26 Jan 2005, Norman Walsh wrote:
> We don't want to make the empty string magic.
> We want xml:id="" to behave analogously to
> how id="" (where id is declared ID) behaves.

I agree.

I have nothing against the xml:id attribute always being of type ID. I 
merely request that the xml:id specification not imply that an attribute 
of type ID that has no value beyond the empty string assign the empty 
string to the element as its ID.

That is, it should state that an attribute of type ID whose value is blank 
does not associate its element with the empty string as an ID.

One example of why this is important is that some languages, for instance 
W3C Selectors, do not have a way to represent empty IDs. Thus, describing 
a document containing an element with an empty xml:id attribute would be 
impossible using that language if an empty xml:id attribute implied the 
element had an empty string ID.

For XML IDs processing is underdefined and therefore UAs are compliant 
either way. However, xml:id is (thankfully) much more detailed in its 
processing model, which is why getting this right matters.

I disagree with this resolution.

You may use this e-mail in your disposition of comments to the director if 
you do not wish to resolve this issue in my favour before moving to CR.

Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'
Received on Thursday, 27 January 2005 10:58:21 UTC

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