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CURIEs and blank nodes (Test #140)

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CURIEs and blank nodes (Test #140)

Dan Connolly
My code fails Test #140, so I'm checking the spec
to find out why.

In section 7. CURIE Syntax Definition
  http://www.w3.org/TR/rdfa-syntax/#s_curies

we find:

  A CURIE is a representation of a full URI.

That contradicts other parts of the spec. I suggest
making it true by constraining the syntax of CURIEs
to exclude the _:foo construct.

The other alternative is to say something like:

 A CURIE is a representation of either an absolute IRI or a blank node.

or fudge it a la:

 A CURIE typically represents an absolute URI.

(does the RDFa spec exclude IRIs on purpose? It's somewhat lax about
the difference between a URI (which, strictly speaking, is
always absolute) and a URI reference (which may be relative). I
wonder if it similarly uses URI where the standard term is
actually IRI.)


--
Dan Connolly, W3C http://www.w3.org/People/Connolly/
gpg D3C2 887B 0F92 6005 C541  0875 0F91 96DE 6E52 C29E


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Re: CURIEs and blank nodes (Test #140)

Ivan Herman-2


On 2010-2-9 03:16 , Dan Connolly wrote:

> My code fails Test #140, so I'm checking the spec
> to find out why.
>
> In section 7. CURIE Syntax Definition
>   http://www.w3.org/TR/rdfa-syntax/#s_curies
>
> we find:
>
>   A CURIE is a representation of a full URI.
>
> That contradicts other parts of the spec. I suggest
> making it true by constraining the syntax of CURIEs
> to exclude the _:foo construct.
>
> The other alternative is to say something like:
>
>  A CURIE is a representation of either an absolute IRI or a blank node.
I would definitely prefer this one. Excluding the _:xxx would be a
problem. There are some (albeit rare) cases when explicit reference to
blank nodes are necessary (eg, if lists are encoded).

>
> or fudge it a la:
>
>  A CURIE typically represents an absolute URI.
>

I do not have problem with that either.

> (does the RDFa spec exclude IRIs on purpose? It's somewhat lax about
> the difference between a URI (which, strictly speaking, is
> always absolute) and a URI reference (which may be relative). I
> wonder if it similarly uses URI where the standard term is
> actually IRI.)

I guess bringing in the IRI issue may be one of the things that the RDFa
WG will have to settle for 1.1. That being said, the current RDF spec
refer to URI-s only, that may be the reason that RDFa sticked to URI-s

(I must admit that the whole URI/IRI issue never ceases to confuse me. I
should really take some time diving into this one day...)

Thanks

ivan


>
>

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Re: CURIEs and blank nodes (Test #140)

Dan Connolly
On Tue, 2010-02-09 at 13:06 +0100, Ivan Herman wrote:

>
> On 2010-2-9 03:16 , Dan Connolly wrote:
> > My code fails Test #140, so I'm checking the spec
> > to find out why.
> >
> > In section 7. CURIE Syntax Definition
> >   http://www.w3.org/TR/rdfa-syntax/#s_curies
> >
> > we find:
> >
> >   A CURIE is a representation of a full URI.
> >
> > That contradicts other parts of the spec. I suggest
> > making it true by constraining the syntax of CURIEs
> > to exclude the _:foo construct.
> >
> > The other alternative is to say something like:
> >
> >  A CURIE is a representation of either an absolute IRI or a blank node.
>
> I would definitely prefer this one. Excluding the _:xxx would be a
> problem. There are some (albeit rare) cases when explicit reference to
> blank nodes are necessary (eg, if lists are encoded).

I'm not talking about changing RDFa functionality; I'm just
talking about spec terminology. I'm suggesting that _:foo
is allowed and works just like you prefer, but it's not
called a CURIE, but a blankID or some such.

>
> >
> > or fudge it a la:
> >
> >  A CURIE typically represents an absolute URI.
> >
>
> I do not have problem with that either.
>
> > (does the RDFa spec exclude IRIs on purpose? It's somewhat lax about
> > the difference between a URI (which, strictly speaking, is
> > always absolute) and a URI reference (which may be relative). I
> > wonder if it similarly uses URI where the standard term is
> > actually IRI.)
>
> I guess bringing in the IRI issue may be one of the things that the RDFa
> WG will have to settle for 1.1. That being said, the current RDF spec
> refer to URI-s only,

No, it doesn't. See section 6.4 RDF URI References
http://www.w3.org/TR/rdf-concepts/#section-Graph-URIref
http://www.w3.org/TR/rdf-concepts/#dfn-URI-reference

Note that the 2004 RDF specs use "URI reference" in order to
include #fragments, which were not part of URIs in the URI spec
at the time (RFC2396). The current URI standard (RFC3986)
includes #fragments in URIs.

>  that may be the reason that RDFa sticked to URI-s
>
> (I must admit that the whole URI/IRI issue never ceases to confuse me. I
> should really take some time diving into this one day...)
>
> Thanks
>
> ivan


--
Dan Connolly, W3C http://www.w3.org/People/Connolly/
gpg D3C2 887B 0F92 6005 C541  0875 0F91 96DE 6E52 C29E


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Re: CURIEs and blank nodes (Test #140)

Shane McCarron


Dan Connolly wrote:
> No, it doesn't. See section 6.4 RDF URI References
> http://www.w3.org/TR/rdf-concepts/#section-Graph-URIref
> http://www.w3.org/TR/rdf-concepts/#dfn-URI-reference
>
> Note that the 2004 RDF specs use "URI reference" in order to
> include #fragments, which were not part of URIs in the URI spec
> at the time (RFC2396). The current URI standard (RFC3986)
> includes #fragments in URIs.
Hmmm...  if we want to get technical, the RDFa Syntax Specification is
based upon XHTML Modularization, and brings in its datatype definitions
from there.  URI in XHTML Modularization is defined as the XML Schema
datatype anyURI [1] [2].  It was my impression that anyURI permitted
IRIs.  Steven?  This was your thing.

[1] http://www.w3.org/TR/xhtml-modularization/abstraction.html#dt_URI
[2] http://www.w3.org/TR/2004/REC-xmlschema-2-20041028/#anyURI

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Re: CURIEs and blank nodes (Test #140)

Dan Connolly
On Tue, 2010-02-09 at 10:05 -0600, Shane McCarron wrote:

>
> Dan Connolly wrote:
> > No, it doesn't. See section 6.4 RDF URI References
> > http://www.w3.org/TR/rdf-concepts/#section-Graph-URIref
> > http://www.w3.org/TR/rdf-concepts/#dfn-URI-reference
> >
> > Note that the 2004 RDF specs use "URI reference" in order to
> > include #fragments, which were not part of URIs in the URI spec
> > at the time (RFC2396). The current URI standard (RFC3986)
> > includes #fragments in URIs.
> Hmmm...  if we want to get technical, the RDFa Syntax Specification is
> based upon XHTML Modularization, and brings in its datatype definitions
> from there.  URI in XHTML Modularization is defined as the XML Schema
> datatype anyURI [1] [2].

That jives with sectioni 6.4 of the RDF spec:

"Note: RDF URI references are compatible with the anyURI datatype as
defined by XML schema datatypes [XML-SCHEMA2], constrained to be an
absolute rather than a relative URI reference."

>   It was my impression that anyURI permitted
> IRIs.

Yes, more or less.

>   Steven?  This was your thing.
>
> [1] http://www.w3.org/TR/xhtml-modularization/abstraction.html#dt_URI
> [2] http://www.w3.org/TR/2004/REC-xmlschema-2-20041028/#anyURI
>


--
Dan Connolly, W3C http://www.w3.org/People/Connolly/
gpg D3C2 887B 0F92 6005 C541  0875 0F91 96DE 6E52 C29E


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Re: CURIEs and blank nodes (Test #140)

Julian Reschke
In reply to this post by Dan Connolly
Dan Connolly wrote:
> ...
> Note that the 2004 RDF specs use "URI reference" in order to
> include #fragments, which were not part of URIs in the URI spec
> at the time (RFC2396). The current URI standard (RFC3986)
> includes #fragments in URIs.
> ...

I think it would be more correct to say that RFC 2396 didn't have a
specific ABNF production for absoluteURI + fragment. The ABNF production
"URI" is new in RFC 3986.

Best regards, Julian

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