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Re: [XBL] XBL 2.0 - Selectors for parsing, and XPath?

From: Ian Hickson <ian@hixie.ch>
Date: Fri, 6 Oct 2006 00:05:30 +0000 (UTC)
To: karl@w3.org
Cc: public-appformats@w3.org
Message-ID: <Pine.LNX.4.62.0610052357330.19875@dhalsim.dreamhost.com>

On Thu, 5 Oct 2006 karl@w3.org wrote:
>
> The specification defines a MUST requirement for parsing the document.

The statement in question is:

# The element attribute of the binding element and the includes attribute 
# of the content element, if specified, must be parsed according to the 
# rules in the Selectors specification. [SELECTORS]

The requirement is not a requirement on how to parse the document, merely 
a requirement on how to parse the values of two specific attributes. Those 
attributes are defined as containing Selectors, so it seems wise to 
require that they be parsed according to the rules of the Selectors 
specification.


> It makes then impossible for a conformant parser to use XPath (or any 
> kind of parsing method like regex) to parse the document.

Any parsing mechanism can be used to parse documents containing XBL, the 
requirement quoted above is merely requiring that whatever parsing 
mechanism is used, it implement the semantics of the Selectors language 
for the purposes of the two attributes mentioned.



> Many XML tools have already implemented XPath and it doesn't seem there 
> are a lot implementing Selectors. It would be better to not have a MUST 
> on this requirement. Does it bring any benefits to impose the parsing 
> rules?

Hopfully this has clarified the confusion and removed the misunderstanding 
that any particular parsing mechanism must be used. (The parsing _rules_ 
must be defined, obviously, so that interoperability can be obtained. 
However that is separate from what technology is used to implement the 
parsing -- be it Perl Regular Expressions, LEX, expat, or whatever.)


> Selectors is also still a Working Draft. It means the XBL 2.0 
> specification will not be able to reach Rec until Selectors have itself 
> reached PR.

Selectors will reach PR far, far before XBL reaches PR. (Selectors has 
been in CR for several years and is ready to go to PR, it is merely 
awaiting the final writing of its implementation report. XBL2 doesn't even 
have a test suite yet.)


Please let me know if this removes your objection.

Cheers,
-- 
Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'
Received on Friday, 6 October 2006 00:05:45 UTC

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