Re: http://w3c.github.io/data-shapes/semantics with negated recursion

Peter,

I am having trouble parsing your example against the abstract syntax
given in [1]. Perhaps you have abbreviated it or is the grammar wrong?

Your example is:
S = { s closed ex:r !s [1;1] and ^ex:r iri [1,1] }
Here I assume S is the schema, s is a ShapeLabel, and we are dealing
with a ClosedShape.
Therefore the following must be a ShapeExpr:
ex:r !s [1;1] and ^ex:r iri [1,1]

However, the 'and' operator only appears in ConjShapeConstraint where
it combines other ShapeLabel's. How does one form conjunctions of
constraints?

[1] http://w3c.github.io/data-shapes/semantics/

On Wed, Jun 24, 2015 at 1:22 PM, Peter F. Patel-Schneider
<pfpschneider@gmail.com> wrote:
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> The behaviour of http://w3c.github.io/data-shapes/semantics on simple
> negated recursive shapes is quite bizarre.
>
> Consider
> S = { s closed ex:r !s [1;1] and ^ex:r iri [1,1] }
> on graphs of the form
> Gn = { ex:i1 ex:r ex:i2 .
>        ex:i2 ex:r ex:i3 .
>        ... .
>        ex:in ex:r ex:i1 . }
>
> The valid typings for these graphs appear quite random and also quite
> computationally difficult to determine.
>
> peter
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Received on Wednesday, 24 June 2015 20:40:16 UTC