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Re: is there an implementation of Shape Expressions that correctly handles recursive shapes?

From: Peter F. Patel-Schneider <pfpschneider@gmail.com>
Date: Tue, 24 Mar 2015 15:28:05 -0700
Message-ID: <5511E4F5.1070509@gmail.com>
To: Eric Prud'hommeaux <eric@w3.org>
CC: RDF Data Shapes Working Group <public-data-shapes-wg@w3.org>
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I don't think that the fix is to add extra explanation here.

Based on my analyses, the problem is with two of the three formal
specification of Shape Expressions. Any implementation of either of these
two specifications is going to be problematic. Based on a bit of testing it
appears that the Fancy ShEx Demo is based on an implementation of the
axiomatic semantics.

I'm looking at the system that Iovka sent me, as it appears to be based on
the third formal specification of Shape Expressions, but it appears that
that system uses some syntax other than the Shape Expressions syntax as
defined in the W3C Submission.

peter


On 03/24/2015 03:10 PM, Eric Prud'hommeaux wrote:
> * Peter F. Patel-Schneider <pfpschneider@gmail.com> [2015-03-22 
> 10:37-0700]
>> That's working better now.  At least we are getting to the Shape 
>> Expressions problems.
>> 
>> I have attached two screen shots showing different behaviour on the 
>> same graph.
> 
> I've added a bit to note inconsistencies between different models. I 
> don't know of a real answer to a two-party liars' paradox, but you may 
> find the disclosures more revealing and consistent.
> 
> http://www.w3.org/2013/ShEx/FancyShExDemo?starting-nodes=ex%3Ab%20ex%3Ac&sch
ema=PREFIX%20ex%3A%20%3Chttp%3A%2F%2Fex.example%2F%23%3E%0Astart%3D%3CT%3E%0A%
3CT%3E%20%7B%20ex%3Aq%20.%20%7C%20ex%3Ar%20%40%3CT%3E%20%7D%0A&data=PREFIX%20e
x%3A%20%3Chttp%3A%2F%2Fex.example%2F%23%3E%0Aex%3Ab%20ex%3Aq%20ex%3Az%20.%0Aex
%3Ab%20ex%3Ar%20ex%3Ac%20.%0Aex%3Ac%20ex%3Aq%20ex%3Az%20.%0Aex%3Ac%20ex%3Ar%20
ex%3Ab%20.&colorize=true
>
>
> 
BTW, since the browser-dependent bugs appear to have subsided, you
> probably only need to send me a permalinks.
> 
> 
>> peter
> 
> 
> 
> 
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Received on Tuesday, 24 March 2015 22:28:36 UTC

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