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

* Peter F. Patel-Schneider <pfpschneider@gmail.com> [2015-03-24 15:28-0700]
> 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.

If the goal is to match the users' expectations, I would expect that
exploring all possible models would do that. For instance, if we say
  ex:b matches <T> iff ex:c fails <T>
  ex:c matches <T> iff ex:b fails <T>
, we've covered the possible solutions. An alternative is to say that
  ex:b matches <T>
  ex:c matches <T>
because they don't pass in all models. By tracking the node/shape pairs
involved in a particular solution, I think we can cheaply explore the
permutations of A iff !B. If this doesn't appeal, what do you propose
is a good answer to your dilema?


> 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.

I think it's useful to give users the ability to see what parts of the
graph weren't covered by the graph


> 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
> > 
> > 
> > 
> > 

-- 
-ericP

office: +1.617.599.3509
mobile: +33.6.80.80.35.59

(eric@w3.org)
Feel free to forward this message to any list for any purpose other than
email address distribution.

There are subtle nuances encoded in font variation and clever layout
which can only be seen by printing this message on high-clay paper.

Received on Wednesday, 25 March 2015 07:02:53 UTC