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Re: chaining-friendly rules for @instanceof

From: Mark Birbeck <mark.birbeck@formsPlayer.com>
Date: Thu, 15 Nov 2007 10:18:04 +0000
Message-Id: <22893BF6-1624-4011-9FE9-6BFDAF2C270E@formsPlayer.com>
Cc: Ben Adida <ben@adida.net>, RDFa <public-rdf-in-xhtml-tf@w3.org>
To: Ivan Herman <ivan@w3.org>

Hi Ivan,

> I am sorry, but you make this very difficult for some of us. I  
> think the
> majority of the participants of this TF, including myself, have no  
> idea
> what you are talking about when you refer to 'old chaining rules in
> RDFa'. And, frankly, I do not have the time, nor the will, to go  
> back to
> old mails and archives which are probably two years old...
> Bottomline: would it be possible for those of us who are newbies in  
> the
> group to summarize what would be your proposal at this moment to solve
> the @instanceof deadlock? So that we could compare the two and make a
> decision?

Obviously I don't want to create work for everyone. :) And I  
certainly wasn't expecting everyone to trawl through old drafts. But  
I'm not sure I could have made my intentions any clearer than putting  
them right up front in the first paragraph of my post ;):

>> I've written and re-written the following post umpteen times, over  
>> the
>> last month or so. :) Finally, I've decided that the best way to break
>> this down is to explain why I disagree with your approach, and then
>> separately to spell out the extra couple of rules we need to make  
>> your
>> use-cases work. All attempts I've made to mix the two have been even
>> longer than this email...and as you can see below, this shortened
>> version is still pretty long!

So, yes...my proposed rules will follow (just finishing the post  
now). But I wanted to make as clear as possible what the problems are  
with Ben's @instanceof rule, and it was proving difficult to do that  
whilst at the same time trying to explain alternate rules. (I have  
been working on this for weeks, unfortunately.) That's why I split  
the whole thing into two.

Essentially, there is a major problem with Ben's rule for  
@instanceof, that causes items to change their meaning (a) when  
brought into a relationship with something else, and (b) when @about  
is removed from a statement that has a whole bunch of attributes. I  
don't believe that anyone had really realised quite the level of  
inconsistencies that the @instanceof rule brought with it, until I  
spelt them out in this (very) long post. :)

Certainly I hadn't, and Manu also said that he hadn't, so whether  
people read all of the post or not, I think it was worth breaking the  
problem down in detail, so that we now have a complete reference of  
all the issues.

One last thing, I want to emphasise that the way @instanceof behaves  
is the only rule where I see a problem. As far as I can tell, if we  
remove that rule, then Ben has essentially independently  
'reconstructed' a lot of what we used to have, and to me that's a  
good sign, since it implies (a) that the feature is useful, and (b)  
that this way of doing it is logical.



   Mark Birbeck, formsPlayer

   mark.birbeck@formsPlayer.com | +44 (0) 20 7689 9232
   http://www.formsPlayer.com | http://internet-apps.blogspot.com

   standards. innovation.
Received on Thursday, 15 November 2007 10:18:29 UTC

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