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Re: [XBL] XBL 2.0 Expected context, Expected children

From: Ian Hickson <ian@hixie.ch>
Date: Fri, 13 Oct 2006 17:50:33 +0000 (UTC)
To: Karl Dubost <karl@w3.org>
Cc: public-appformats@w3.org
Message-ID: <Pine.LNX.4.62.0610131747410.18283@dhalsim.dreamhost.com>
On Thu, 12 Oct 2006, Karl Dubost wrote:
> 
> Le 06-10-12 à 07:20, Ian Hickson a écrit :
> > > The sentence is better.
> > > Are there unexpected contexts? Is "expected" word necessary?
> > 
> > Well, any context that isn't expected is unexpected.
> 
> expected context  -> parents
> expected children -> children

No, the actual parents and children depend on what the markup is. For 
example, in this (non-conforming) extract:

   <xbl xmlns="http://www.w3.org/ns/xbl">
     <style>
     </style>
   </xbl>

...the parent of the <style> is an <xbl>, but the _expected context_ of a 
<style> is a <resources> element.


> > > Do you mean because of multi namespaces? What are the precise 
> > > syntactical requirements which can't be expressed?
> > 
> > Well, for instance, how do you express the syntactic requirements for 
> > the "includes" attribute? (i.e. that it must contain a syntactically 
> > valid Selector?)
> 
> It is unrelated and entirely dependent on another grammar depending from 
> another technology.

The HTML validator has shown that this argument results in conformance 
checkers that don't actually check for conformance. IMHO it is far more 
damaging to have an incomplete "formal grammar" than it is to force 
conformance checkers to write their own according to the spec.


> > Or, hwo do you express the content model of the <script> element, 
> > given that it is dependent on the script-type="" attribute on the 
> > <xbl> element?
> 
> This one is unrelated and entirely dependent on another grammar 
> depending from the technology used in the content.

Again, it's a requirement expressed by the prose. If the formal grammar 
doesn't express it, then it isn't complete, and is effectively a waste of 
time.

-- 
Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'
Received on Friday, 13 October 2006 17:50:46 UTC

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